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Encyclopedia > Extrasolar planet

An extrasolar planet, or exoplanet, is a planet beyond the Solar System. As of April 2008, 287 exoplanets have been detected.[1] The vast majority were detected through various indirect methods rather than actual imaging.[1] Most of them are massive giant planets likely to resemble Jupiter. This article is about the astronomical term. ... This article is about the Solar System. ... Why do gas giants have this name? This article or section does not cite its references or sources. ... For other uses, see Jupiter (disambiguation). ...

False-color infrared image of the brown dwarf 2M1207 (blue) and its planetary companion 2M1207b (red), as viewed by the Very Large Telescope. As of September 2006 this is the only confirmed extrasolar planet to have been directly imaged.

Extrasolar planets became a subject of scientific investigation in the mid-19th century. Astronomers generally supposed that some existed, it was not known how common they were and how similar they were to the planets of the Solar System. The first confirmed detections were made in the 1990s; since 2000, more than 15 have been discovered every year. The frequency of detection is increasing with 61 planets detected in 2007. It is estimated that at least 10% of sun-like stars have planets, and the true proportion may be much higher.[2] The discovery of extrasolar planets sharpens the question of whether some might support extraterrestrial life.[3] Image File history File links Phot-14a-05-preview. ... Image File history File links Phot-14a-05-preview. ... 2M1207, 2M1207A or 2MASSW J1207334-393254 is a brown dwarf star located in the constellation Hydra; a companion object, 2M1207b, is believed to be one of the first extrasolar planets to be directly imaged, and is the first exoplanet to be discovered in orbit of a brown dwarf. ... 2M1207b is an extrasolar planet orbiting the brown dwarf 2M1207, a star in the constellation Hydra approximately 200 light years from Earth. ... One of the four telescopes that make up the VLT, named Kueyen. ... September 2006 is the ninth month of 2006 and has begun on a Friday. ... For other uses, see Astronomy (disambiguation). ... Sol redirects here. ... Green people redirects here. ...


Currently Gliese 581 d, the third planet of the red dwarf star Gliese 581 (approximately 20 light years from Earth), appears to be the best example yet discovered of a possible terrestrial exoplanet which orbits close to the habitable zone of space surrounding its star. Going by strict terms, it appears to reside outside the "Goldilocks Zone", but the greenhouse effect may raise the planet's surface temperature to that which would support liquid water. Gliese 581 d is an extrasolar planet orbiting the red dwarf star Gliese 581. ... This article is about the British sitcom. ... Gliese 581 (IPA: ) is an M2. ... A light-year or lightyear (symbol: ly) is a unit of measurement of length, specifically the distance light travels in vacuum in one year. ... This article is about Earth as a planet. ... The inner planets, Mercury, Venus, Earth, and Mars, their sizes to scale. ... It has been suggested that Goldilocks phenomenon be merged into this article or section. ... It has been suggested that this article or section be merged into Habitable zone. ... Wikinews has related news: Scientists warn thawing Siberia may trigger global meltdown A schematic representation of the exchanges of energy between outer space, the Earths atmosphere, and the Earth surface. ...

Contents

History of detection

Retracted discoveries

Unconfirmed until 1988, extrasolar planets have long been assumed as plausible, and speculation on planets circling around the fixed stars dates to at least the early 18th century, with Isaac Newton's General Scholium (1713), which has "And if the fixed Stars are the centers of other like systems, these, being form'd by the like wise counsel, must be all subject to the dominion of One" (trans. Motte 1729). Sir Isaac Newton FRS (4 January 1643 – 31 March 1727) [ OS: 25 December 1642 – 20 March 1727][1] was an English physicist, mathematician, astronomer, natural philosopher, and alchemist. ... Newtons own copy of his Principia, with handwritten corrections for the second edition. ...

Our solar system compared with the system of 55 Cancri
Our solar system compared with the system of 55 Cancri

Claims about detection of exoplanets have been made from the 19th century. Some of the earliest involve the binary star 70 Ophiuchi. In 1855, Capt. W. S. Jacob at the East India Company's Madras Observatory reported that orbital anomalies made it "highly probable" that there was a "planetary body" in this system.[4] In the 1890s, Thomas J. J. See of the University of Chicago and the United States Naval Observatory stated that the orbital anomalies proved the existence of a dark body in the 70 Ophiuchi system with a 36-year period around one of the stars.[5] However, Forest Ray Moulton soon published a paper proving that a three-body system with those orbital parameters would be highly unstable.[6] During the 1950s and 1960s, Peter van de Kamp of Swarthmore College made another prominent series of detection claims, this time for planets orbiting Barnard's Star.[7] Astronomers now generally regard all the early reports of detection as erroneous. Image File history File links Extrasolar_planet_NASA2. ... Image File history File links Extrasolar_planet_NASA2. ... 55 Cancri (abbreviated 55 Cnc; Bayer designation ρ1 Cancri, Rho-1 Cancri) is a nearby 6th magnitude star in the constellation Cancer. ... For the band of the same name, see: Binary Star (band) Hubble image of the Sirius binary system, in which Sirius B can be clearly distinguished (lower left). ... 70 Ophiuchi is a binary star system 16. ... The British East India Company, sometimes referred to as John Company, was the first joint-stock company (the Dutch East India Company was the first to issue public stock). ... The Madras Observatory was founded by the British East India Company in 1786 in Chennai (then Madras). ... Thomas Jefferson Jackson (T. J. J.) See, (1866 to July 4, 1962). ... For other uses, see University of Chicago (disambiguation). ... Aerial view of USNO. The United States Naval Observatory (USNO) is one of the oldest scientific agencies in the United States. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... Forest Ray Moulton (April 29, 1872 – December 7, 1952) was a U.S. astronomer. ... Piet van de Kamp (December 26, 1901 – May 18, 1995), known as Peter van de Kamp in the United States, was a Dutch-American astronomer. ... Swarthmore College is a private, independent, liberal arts college in the United States with an enrollment of about 1,450 students. ... Barnards Star is a very low-mass star in the constellation Ophiuchus which was discovered by the astronomer E. E. Barnard in 1916. ...


In 1991, Andrew Lyne, M. Bailes and S.L. Shemar claimed to have discovered a pulsar planet in orbit around PSR 1829-10, using pulsar timing variations.[8] The claim briefly received intense attention, but Lyne and his team soon retracted it.[9] Andrew G. Lyne FRS (born 1942) is a British physicist. ... An artists conception of PSR 1257+12s system of planets Pulsars are rapidly rotating neutron stars. ... PSR 1829-10 is a pulsar located in the Scutum Constellation. ... Any planet is an extremely faint light source compared to its parent star. ...

Our inner solar system superimposed behind the orbits of the planets HD 179949 b, HD 164427 b, Epsilon Reticuli Ab, and Mu Arae b (all parent stars are in the center)
Our inner solar system superimposed behind the orbits of the planets HD 179949 b, HD 164427 b, Epsilon Reticuli Ab, and Mu Arae b (all parent stars are in the center)

Image File history File links Download high-resolution version (678x645, 127 KB) Source: http://origins. ... Image File history File links Download high-resolution version (678x645, 127 KB) Source: http://origins. ... HD 179949 is a 6th magnitude star in the constellation of Sagittarius. ... Our inner solar system superimposed behind the orbits of the planets HD 179949 b, HD 164427 b, Epsilon Reticuli ab, and Mu Arae b (each planet has its parent star labeled next to it -- all parent stars are in the center) Epsilon Reticuli (ε Ret / ε Reticuli) is a 4th magnitude star... Mu Arae (μ Ara / μ Arae) is a Sunlike yellow-orange star located around 50 light years away in the constellation Ara. ...

Published discoveries

The first published discovery to have received subsequent confirmation was made in 1988 by the Canadian astronomers Bruce Campbell, G. A. H. Walker, and S. Yang.[10] Their radial-velocity observations suggested that a planet orbited the star Gamma Cephei. They remained cautious about claiming a true planetary detection, and widespread skepticism persisted in the astronomical community for several years about this and other similar observations. It was mainly because the observations were at the very limits of instrumental capabilities at the time. Another source of confusion was that some of the possible planets might instead have been brown dwarfs, objects that are intermediate in mass between planets and stars. Gamma Cephei (γ Cep / γ Cephei) is a star in the constellation Cepheus. ... This brown dwarf (smaller object) orbits the star Gliese 229, which is located in the constellation Lepus about 19 light years from Earth. ...


The following year, additional observations were published by John Berry that supported the reality of the planet orbiting Gamma Cephei,[11] though subsequent work in 1992 raised serious doubts.[12] Finally, in 2003, improved techniques allowed the planet's existence to be confirmed.[13]


In early 1992, radio astronomers Aleksander Wolszczan and Dale Frail announced the discovery of planets around another pulsar, PSR 1257+12.[14] This discovery was quickly confirmed, and is generally considered to be the first definitive detection of exoplanets. These pulsar planets are believed to have formed from the unusual remnants of the supernova that produced the pulsar, in a second round of planet formation, or else to be the remaining rocky cores of gas giants that survived the supernova and then spiraled into their current orbits. Aleksander Wolszczan (b. ... Dale Frail is an astronomer. ... It has been suggested that Radio pulsar be merged into this article or section. ... PSR 1257+12 (also catalogued as PSR B1257+12, PSR 1300+1240, or PSR J1300+1240) is a pulsar located 980 light years from Earth. ... For other uses, see Supernova (disambiguation). ... This article does not cite any references or sources. ...


On October 6, 1995, Michel Mayor and Didier Queloz of the University of Geneva announced the first definitive detection of an exoplanet orbiting an ordinary main-sequence star (51 Pegasi).[15] This discovery was made at the Observatoire de Haute-Provence and ushered in the modern era of exoplanetary discovery. Technological advances, most notably in high-resolution spectroscopy, led to the detection of many new exoplanets at a rapid rate. These advances allowed astronomers to detect exoplanets indirectly by measuring their gravitational influence on the motion of their parent stars. Several extrasolar planets were eventually also detected by observing the variation in a star's apparent luminosity as a planet passed in front of it. is the 279th day of the year (280th in leap years) in the Gregorian calendar. ... Year 1995 (MCMXCV) was a common year starting on Sunday. ... Michel Mayor (born 12 January 1942) is a professor in the Department of Astronomy at the University of Geneva. ... Didier Queloz, born 23 February 1966, is a Geneva-based astronomer with a prolific record in finding extrasolar planets. ... The University of Geneva (Université de Genève) is a university in Geneva, Switzerland. ... Hertzsprung-Russell diagram The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. ... 51 Pegasi (Flamsteed designation, HIP 113357 in the Hipparcos Catalogue, HD 217014 in the Henry Draper Catalogue) is the name of a Sun-like star 14. ... The Observatoire de Haute-Provence (OHP) was created in 1937 as a national facility for French astronomers although the first plans for a privately financed observatory date from as early as 1923. ... Animation of the dispersion of light as it travels through a triangular prism. ... Gravity is a force of attraction that acts between bodies that have mass. ...


To date, 287 exoplanets have been found,[1] including a few that were confirmations of controversial claims from the late 1980s. The first system to have more than one planet detected was υ And. Twenty such multiple-planet systems are now known. Among the known exoplanets are four pulsar planets orbiting two separate pulsars. Infrared observations of circumstellar dust disks also suggest the existence of millions of comets in several extrasolar systems. Upsilon Andromedae (Ï… And ) is a star, approximately 44 light-years from Earth, and approximately 3 billion years old, two thirds the age of our Sun. ... For other uses, see Infrared (disambiguation). ... Comet Hale-Bopp Comet West For other uses, see Comet (disambiguation). ...


Detection methods

Planets are extremely faint light sources compared to their parent stars. At visible wavelengths, they usually have less than a millionth of their parent star's brightness. In addition to the intrinsic difficulty of detecting such a faint light source, the parent star causes a glare that washes it out. Any planet is an extremely faint light source compared to its parent star. ...


For those reasons, current telescopes can only directly image exoplanets under exceptional circumstances. Specifically, it may be possible when the planet is especially large (considerably larger than Jupiter), widely separated from its parent star, and hot so that it emits intense infrared radiation. This article does not cite any references or sources. ... Any planet is an extremely faint light source compared to its parent star. ... For other uses, see Jupiter (disambiguation). ...


The vast majority of known extrasolar planets have been discovered through indirect methods:

Diagram showing how an exoplanet orbiting a larger star could produce changes in position and velocity of the star as they orbit their common center of mass.
Diagram showing how an exoplanet orbiting a larger star could produce changes in position and velocity of the star as they orbit their common center of mass.
  • Astrometry: Astrometry consists of precisely measuring a star's position in the sky and observing the ways in which that position changes over time. If the star has a planet, then the gravitational influence of the planet will cause the star itself to move in a tiny circular or elliptical orbit about their common center of mass (see video on the right).
  • Radial velocity or Doppler method: Variations in the speed with which the star moves towards or away from Earth — that is, variations in the radial velocity of the star with respect to Earth — can be deduced from the displacement in the parent star's spectral lines due to the Doppler effect[16]. This has been by far the most productive technique used.
  • Pulsar timing: A pulsar (the small, ultradense remnant of a star that has exploded as a supernova) emits radio waves extremely regularly as it rotates. Slight anomalies in the timing of its observed radio pulses can be used to track changes in the pulsar's motion caused by the presence of planets.
  • Transit method: If a planet crosses (or transits) in front of its parent star's disk, then the observed brightness of the star drops by a small amount. The amount by which the star dims depends on its size and on the size of the planet.
  • Gravitational microlensing: Microlensing occurs when the gravitational field of a star acts like a lens, magnifying the light of a distant background star. Possible planets orbiting the foreground star can cause detectable anomalies in the lensing event light curve.
  • Circumstellar disks: Disks of space dust surround many stars, and this dust can be detected because it absorbs ordinary starlight and re-emits it as infrared radiation. Features in dust disks may suggest the presence of planets.
  • Eclipsing binary: In an eclipsing double star system, the planet can be detected by finding variability in minima as it goes back and forth. It is the most reliable method for detecting planets in binary star systems.
  • Orbital phase: Like the phase of the Moon and Venus, extrasolar planets also have phases. Orbital phases depends on inclination of the orbit. By studying orbital phases scientists can calculate particle sizes in the atmospheres of planets.
  • Polarimetry: Stellar light becomes polarized when it interacts with atmospheric molecules, which could be detected with a polarimeter. So far one planet has been studied by this method.

Not counting a few exceptions, all known extrasolar planet candidates have been found using ground-based telescopes. However, many of the methods can yield better results if the observing telescope is located above the restless atmosphere. COROT (launched in December, 2006) is the only active space mission dedicated to extrasolar planet search. Hubble Space Telescope has also found or confirmed a few planets. There are many planned or proposed space missions such as Kepler, New Worlds Mission, Darwin, Space Interferometry Mission, Terrestrial Planet Finder, and PEGASE. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Any planet is an extremely faint light source compared to its parent star. ... In astrodynamics or celestial mechanics a elliptic orbit is an orbit with the eccentricity greater than 0 and less than 1. ... Any planet is an extremely faint light source compared to its parent star. ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ... A source of waves moving to the left. ... Any planet is an extremely faint light source compared to its parent star. ... It has been suggested that Radio pulsar be merged into this article or section. ... For other uses, see Supernova (disambiguation). ... It has been suggested that Radio pulsar be merged into this article or section. ... Any planet is an extremely faint light source compared to its parent star. ... 2003 Transit of Mercury The term transit or astronomical transit has two meanings in astronomy: A transit is the astronomical event that occurs when one celestial body appears to move across the face of another celestial body, as seen by an observer at some particular vantage point. ... Any planet is an extremely faint light source compared to its parent star. ... Any planet is an extremely faint light source compared to its parent star. ... For other uses, see Infrared (disambiguation). ... Any planet is an extremely faint light source compared to its parent star. ... A binary star system consists of two stars both orbiting around their barycenter. ... Any planet is an extremely faint light source compared to its parent star. ... This article is about Earths moon. ... For other uses, see Venus (disambiguation). ... Planetary phase is the term used to describe the appearance of the illuminated section of a planet. ... Any planet is an extremely faint light source compared to its parent star. ... A polarimeter is a scientific instrument for measuring the rotation of the plane of polarized light as it passes through a sample of a compound which exhibits optical activity. ... For a French painter, see Jean-Baptiste-Camille Corot. ... The Hubble Space Telescope (HST; also known colloquially as the Hubble or just Hubble) is a space telescope that was carried into Earth orbit by the Space Shuttle in April 1990. ... The Kepler Mission is a space observatory being developed by NASA that will search for extrasolar planets and will only be the second space-based telescope particularly constructed for that task, the first one being COROT. For this purpose, it will observe the brightness of about 100,000 stars over... This article does not cite any references or sources. ... Darwin is a proposed European Space Agency (ESA) mission designed to directly detect Earth-like planets orbiting nearby stars, and search for evidence of life on these planets. ... Artists concept of Space Interferometry Mission spacecraft The Space Interferometry Mission (SIM), also called SIM PlanetQuest, is a NASA instrument originally expected to be launched in December of 2011; however due to budget cuts it will now launch no sooner than between October 2014 and April 2015. ... Terrestrial Planet Finder - Infrared interferometer concept The Terrestrial Planet Finder (TPF) is a plan by NASA for a telescope system that would be capable of detecting extrasolar terrestrial planets. ... PEGASE is a proposed space mission to build a double-aperture interferometer composed of three free-flying satellites. ...


Nomenclature

A lower-case letter is placed after the star name, starting with "b" for the first planet found in the system (for example, 51 Pegasi b). The next planet is labeled, for example, as "51 Pegasi c", the one following that "51 Pegasi d", and so on. The suffix "a" was intended to refer specifically to the primary, as opposed to the system as a whole, but this did not catch on.[citation needed] 51 Pegasi b (also written as 51 Peg b) is the first planet discovered around a sun-like star outside of the solar system. ...


Note that the letters assigned are based on the order in which the planets are discovered, and not on their position. For example, in the Gliese 876 system, the most recently discovered planet is referred to as Gliese 876 d, despite the fact that it is closer to the star than Gliese 876 b and Gliese 876 c. Nomenclatures often used in science fiction used Roman numerals in the order of planets' positions from the star, but for the above reason, this is not practical. Gliese 876 is a red dwarf star located approximately 15 light-years away in the constellation Aquarius. ... Gliese 876 d is an extrasolar planet orbiting the red dwarf star Gliese 876. ... Gliese 876 b is an extrasolar planet orbiting the red dwarf star Gliese 876 every 60. ... Gliese 876 c is an extrasolar planet orbiting the red dwarf star Gliese 876, taking 30. ... Science fiction is a form of speculative fiction principally dealing with the impact of imagined science and technology, or both, upon society and persons as individuals. ... Roman numerals are a numeral system originating in ancient Rome, adapted from Etruscan numerals. ...


Before the discovery of 51 Pegasi b in 1995, extrasolar planets were named differently. The first extrasolar planets found around pulsar PSR 1257+12 were named with capital letters: PSR 1257+12 B and PSR 1257+12 C. When a new, closer-in exoplanet was found around the pulsar, it was named PSR 1257+12 A, not D. It has been suggested that Radio pulsar be merged into this article or section. ... PSR 1257+12 (also catalogued as PSR B1257+12, PSR 1300+1240, or PSR J1300+1240) is a pulsar located 980 light years from Earth. ... It has been suggested that Radio pulsar be merged into this article or section. ...


Some of the extrasolar planets have unofficial nicknames, as well. For example, HD 209458 b is sometimes called "Osiris," and 51 Pegasi b is called "Bellerophon." Gliese 581 c, the smallest and most Earth-like planet around main-sequence stars, has been called "Ymir."[17] The IAU currently has no plans to officially name extrasolar planets, considering it impractical.[18] HD 209458 b is an extrasolar planet that orbits the Sun-like star HD 209458 in the constellation Pegasus, some 150 light-years from Earths solar system, with evidence of water vapor. ... 51 Pegasi b (also written as 51 Peg b) is the first planet discovered around a sun-like star outside of the solar system. ... Gliese 581 c (IPA: ) is a super-earth extrasolar planet orbiting the red dwarf star Gliese 581. ... IAU redirects here. ...


Definition

Main article: Definition of planet

According to the International Astronomical Union's working definition of "planet," a planet must orbit a star.[19] However, the current IAU definition for planet only accounts for our own solar system and all extrasolar planets were excluded from this definition for now.[20] There have also been reports of free-floating planetary-mass objects (ones not orbiting any star), sometimes called "rogue planets" or "interstellar planets". Such objects are not discussed in this article since they are outside the working definition of "planet". For more information, see rogue planet. Photograph of the planet Neptune and its moon Triton, taken by Voyager 2 as it entered the outer solar system. ... IAU redirects here. ... This article is about the astronomical object. ... This article is being considered for deletion in accordance with Wikipedias deletion policy. ... A rogue planet is a planet that either has an extremely elongated orbit around its star so that it is not on the same orbital plane as the other planets in the system, or it is an interstellar planet, a planet that drifts freely through space and doesnt orbit... A rogue planet is a planet that either has an extremely elongated orbit around its star so that it is not on the same orbital plane as the other planets in the system, or it is an interstellar planet, a planet that drifts freely through space and doesnt orbit...


General properties

Stellar characteristics

Most known exoplanets orbit stars roughly similar to our own Sun, that is, main-sequence stars of spectral categories F, G, or K. One reason is simply that planet search programs have tended to concentrate on such stars. But even after taking this into account, statistical analysis suggests that lower-mass stars (red dwarfs, of spectral category M) are either less likely to have planets or have planets that are themselves of lower mass and hence harder to detect.[21] Recent observations by the Spitzer Space Telescope indicate that stars of spectral category O, which are much hotter than our Sun, produce a photo-evaporation effect that inhibits planetary formation.[22] Sol redirects here. ... Hertzsprung-Russell diagram The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. ... In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequently refined in terms of other characteristics. ... This article is about the British sitcom. ... In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequently refined in terms of other characteristics. ... The Spitzer Space Telescope (formerly the Space Infrared Telescope Facility [SIRTF]) is an infrared space observatory, the fourth and final of NASAs Great Observatories. ... In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequently refined in terms of other characteristics. ... Photo evaporation is the effect when a young stellar object (YSO) disperses its disk by radiation. ...


Stars are composed mainly of the light elements hydrogen and helium. They also contain a small fraction of heavier elements such as iron, and this fraction is referred to as a star's metallicity. Stars of higher metallicity are much more likely to have planets, and the planets they have tend to be more massive than those of lower-metallicity stars.[2] This article is about the chemistry of hydrogen. ... General Name, symbol, number helium, He, 2 Chemical series noble gases Group, period, block 18, 1, s Appearance colorless Standard atomic weight 4. ... General Name, symbol, number iron, Fe, 26 Chemical series transition metals Group, period, block 8, 4, d Appearance lustrous metallic with a grayish tinge Standard atomic weight 55. ... The globular cluster M80. ...


Measured properties

Most known extrasolar planet candidates have been discovered using indirect methods and therefore only certain physical and orbital parameters can be determined. The radial velocity method provides all orbital elements except for inclination. The unknown inclination results in unknown mass and therefore usually only the minimum mass is given. In some cases it may be a much more massive object such as brown dwarf or red dwarf star instead. However, if the planet's orbit is nearly perpendicular to sky (inclination close to 90°), the planet can be seen transiting its star and therefore its true mass and radius can be measured. Furthermore, astrometric observations and dynamical studies in multiple planet systems can be used to constrain the mass of a planet. The elements of an orbit are the parameters needed to specify that orbit uniquely, given a model of two ideal masses obeying the Newtonian laws of motion and the inverse-square law of gravitational attraction. ... For the science fiction novella by William Shunn, see Inclination (novella). ... For the science fiction novella by William Shunn, see Inclination (novella). ... The term true mass is synonymous with the term mass, but is used in astronomy to differentiate the measured mass of a planet from the lower limit of mass usually obtained from radial velocity techniques. ...


Spectroscopic measurements during the transit can be used to study a transiting planet's atmospheric composition.[23] Secondary transit (occurs when the planet is behind the star) can be used for direct detection of infrared radiation from the planet. In addition, infrared observations can be used to study heat patterns on the surface of a closely-orbiting planet.


Selection effect

All extrasolar planets discovered by radial velocity (blue dots), transit (red) and microlensing (yellow) to 31 August 2004. Also shows detection limits of forthcoming space- and ground-based instruments.
All extrasolar planets discovered by radial velocity (blue dots), transit (red) and microlensing (yellow) to 31 August 2004. Also shows detection limits of forthcoming space- and ground-based instruments.

The vast majority of exoplanets found so far have high masses. All but six of them have more than ten times the mass of Earth. Many are considerably more massive than Jupiter, the most massive planet in the Solar System. However, these high masses are in large part due to an observational selection effect: all detection methods are much more likely to discover massive planets. This bias makes statistical analysis difficult, but it appears that lower-mass planets are actually more common than higher-mass ones, at least within a broad mass range that includes all giant planets. In addition, the fact that astronomers have found several planets only a few times more massive than Earth, despite the great difficulty of detecting them, indicates that such planets are fairly common.[2] Download high resolution version (1382x2161, 1149 KB)Taken from the JPL publication Precursor Science for the Terrestrial Planet Finder edited by P.R. Lawson, S.C. Unwin, and C.A. Beichman (JPL Pub 04-014, page 21, fig. ... Download high resolution version (1382x2161, 1149 KB)Taken from the JPL publication Precursor Science for the Terrestrial Planet Finder edited by P.R. Lawson, S.C. Unwin, and C.A. Beichman (JPL Pub 04-014, page 21, fig. ... is the 243rd day of the year (244th in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... This article is about the Solar System. ... A selection effect is seen in experiments or observations where there is a bias in the underlying methodology that leads to results that preferentially include or exclude certain kinds of results. ...


Many exoplanets orbit much closer around their parent star than any planet in our own Solar System orbits around the Sun. Again, that is mainly an observational selection effect. The radial-velocity method is most sensitive to planets with such small orbits. Astronomers were initially very surprised by these "hot Jupiters," but it is now clear that most exoplanets (or at least, most high-mass exoplanets) have much larger orbits, some located in habitable zones where suitable for liquid water and life. It appears plausible that in most exoplanetary systems, there are one or two giant planets with orbits comparable in size to those of Jupiter and Saturn in our own Solar System. Artists impression of roaster extrasolar planet HD 209458b (Osiris). ...


The eccentricity of an orbit is a measure of how elliptical (elongated) it is. Most known exoplanets have quite eccentric orbits. This is not an observational selection effect, since a planet can be detected about a star equally well regardless of the eccentricity of its orbit. The prevalence of elliptical orbits is a major puzzle, since current theories of planetary formation strongly suggest planets should form with circular (that is, non-eccentric) orbits. One possible theory is that small companions such as T dwarfs (methane-bearing brown dwarfs) can hide in such solar systems and can cause the orbits of planets to be extreme.[24] This is also an indication that our own Solar System may be unusual, since all of its planets except for Mercury do follow basically circular orbits.[2] (This page refers to eccitricity in astrodynamics. ... This brown dwarf (smaller object) orbits the star Gliese 229, which is located in the constellation Lepus about 19 light years from Earth. ... This article is about the planet. ...


Unanswered questions

This planetary habitability chart shows where life might exist on extrasolar planets based on our own Solar System and life on Earth.
This planetary habitability chart shows where life might exist on extrasolar planets based on our own Solar System and life on Earth.

Many unanswered questions remain about the properties of exoplanets, such as the details of their composition and the likelihood of possessing moons. The recent discovery that several surveyed exoplanets lacked water showed that there is still much more to be learned about the properties of exoplanets. Another question is whether they might support life. Several planets do have orbits in their parent star's habitable zone, where it should be possible for Earth-like conditions to prevail. Most of those planets are giant planets more similar to Jupiter than to Earth; if these planets have large moons, the moons might be a more plausible abode of life. Detection of life (other than an advanced civilization) at interstellar distances, however, is a tremendously challenging technical task that will not be feasible for many years, even if such life is commonplace. Image File history File links Habitable_zone-en. ... Image File history File links Habitable_zone-en. ... Understanding planetary habitability is partly an extrapolation of the Earths conditions, as it is the only planet currently known to support life. ... This article is about the Solar System. ... This article is about Earth as a planet. ... The term Extrasolar moon refers to a natural (non-man-made) satellite that orbits an extrasolar planet or other extrasolar body larger than itself. ...


Notable extrasolar planets

First discoveries

The first milestone in the discovery of extrasolar planets was in 1992, when Wolszczan and Frail published results in the journal Nature indicating that pulsar planets existed around PSR B1257+12.[14] Wolszczan had discovered the millisecond pulsar in question in 1990 at the Arecibo radio observatory. These were the first exoplanets ever verified, and they are still considered highly unusual in that they orbit a pulsar. Nature is a prominent scientific journal, first published on 4 November 1869. ... An artists conception of PSR 1257+12s system of planets Pulsars are rapidly rotating neutron stars. ... PSR B1257+12 (sometimes abbreviated to PSR 1257+12) is a pulsar located 980 light years from Earth. ... Aleksander Wolszczan (b. ... It has been suggested that Radio pulsar be merged into this article or section. ... The Arecibo Observatory is located approximately 9 miles south-southwest from Arecibo, Puerto Rico (near the extreme southwestern corner of Arecibo pueblo). ... It has been suggested that Radio pulsar be merged into this article or section. ...


The first verified discovery of an exoplanet (51 Pegasi b) orbiting a main sequence star (51 Pegasi) was announced by Michel Mayor and Didier Queloz in Nature on October 6, 1995.[15] Astronomers were initially surprised by this "hot Jupiter" but soon set out to find other similar planets with great success. 51 Pegasi b (also written as 51 Peg b) is the first planet discovered around a sun-like star outside of the solar system. ... Hertzsprung-Russell diagram The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. ... 51 Pegasi (Flamsteed designation, HIP 113357 in the Hipparcos Catalogue, HD 217014 in the Henry Draper Catalogue) is the name of a Sun-like star 14. ... Michel Mayor (born 12 January 1942) is a professor in the Department of Astronomy at the University of Geneva. ... Didier Queloz, born 23 February 1966, is a Geneva-based astronomer with a prolific record in finding extrasolar planets. ...


Other notable discoveries

Since that time, other notable discoveries have included:

1996, 47 Ursae Majoris b
This Jupiter-like planet was the first long-period planet discovered, orbiting at 2.11 AU from the star with the eccentricity of 0.049. There is second companion, initially claimed to orbit some further out, at 3.79 AU.[25] However, the original parameters for the second planet was disproven in 2006, it is now claimed to orbit even further from the star, at 7.73 AU, with the eccentricity of 0.005.[citation needed] Large uncertainties still exist.
1998, Gliese 876 b
The first planet found that orbits around a red dwarf star (Gliese 876). It orbits closer to the star than Mercury is to the Sun. More planets have subsequently been discovered closer to the star.[26]
1999, Upsilon Andromedae
The first multiple-planetary system to be discovered around a main sequence star. It contains three planets, all are Jupiter-like. Planets b, c, d are announced in 1996, 1999, and 1999 respectively. Their masses are 0.687, 1.97, and 3.93 MJ; they orbit at 0.0595, 0.830, and 2.54 AU respectively.[27]
1999, HD 209458 b
This exoplanet, originally discovered with the radial-velocity method, became the first exoplanet to be seen transiting its parent star. The transit detection conclusively confirmed the existence of the planets suspected to be responsible for the radial velocity measurements.[28]
2001, HD 209458 b
Astronomers using the Hubble Space Telescope announced that they had detected the atmosphere of HD 209458 b. They found the spectroscopic signature of sodium in the atmosphere, but at a smaller intensity than expected, suggesting that high clouds obscure the lower atmospheric layers.[29]
2001, Iota Draconis b
The first planet discovered around the giant star. It is an orange giant. This provides evidence for a survival and behavior of planetary systems around giant stars. Giant stars have pulsations that can mimic the presence of planets. The planet is very massive and has a very eccentric orbit. It orbits the average distance of 27.5% further from its star than Earth to the Sun.[30]
Artist's impression of the pulsar planet PSR B1620-26c (discovered in 2003); it is over 12.5 billion years old, making it the oldest known extrasolar planet.
Artist's impression of the pulsar planet PSR B1620-26c (discovered in 2003); it is over 12.5 billion years old, making it the oldest known extrasolar planet.
2003, PSR B1620-26c
On July 10, using information obtained from the Hubble Space Telescope, a team of scientists led by Steinn Sigurdsson confirmed the oldest extrasolar planet yet. The planet is located in the globular star cluster M4, about 5,600 light years from Earth in the constellation Scorpius. This is the only planet known to orbit around a stellar binary; one of the stars in the binary is a pulsar and the other is a white dwarf. The planet has a mass twice that of Jupiter, and is estimated to be 13 billion years old.[31]
2004, Mu Arae d
In August, a planet orbiting Mu Arae with a mass of approximately 14 times that of the Earth was discovered with the European Southern Observatory's HARPS spectrograph. Depending on its composition, it is the first published "hot Neptune" or "super-Earth".[32]
Infrared image of 2M1207 (bluish) and 2M1207b (reddish). The two objects are separated by less than one arc second in Earth's sky. Image taken using the ESO's 8.2 m Yepun VLT.
2004, 2M1207 b
The first planet around a brown dwarf. The planet is also the first to be directly imaged (in infrared). It has 5 Jupiter mass while other estimates give a slightly lower mass. It orbits at 55 AU from the brown dwarf. The brown dwarf mass is only 25 Jupiters. The temperature of gas giant planet is very hot (1250 K), mostly due to gravitational contraction.[33] In late 2005, the parameters changed to 41 AU and has mass of 3.3 Jupiters as a result that the star is closer to Earth than it was originally expected. In 2006, the dust disk was found around 2M1207, providing evidence for a planet formation about the same as typical stars.[34]
2005, Gliese 876 d
In June, a third planet orbiting the red dwarf star Gliese 876 was announced. With a mass estimated at 7.5 times that of Earth, it is currently the second-lightest known exoplanet that orbits an ordinary main-sequence star. It may be rocky in composition. The planet orbits at 0.021 AU with a period of 1.94 days.[35]
2005, HD 149026 b
In July, a planet with the largest core known was announced. The planet, HD 149026 b, orbits the star HD 149026, and has a core that is estimated to be 70 Earth masses, accounting for two-thirds of the planet's mass.[36]
Artist's impression of the planet OGLE-2005-BLG-390Lb (with surface temperature of approximately −220 °C), orbiting its star 20,000 light years (117.5 quadrillion miles) from Earth; this planet was discovered with gravitational microlensing.
Artist's impression of the planet OGLE-2005-BLG-390Lb (with surface temperature of approximately −220 °C), orbiting its star 20,000 light years (117.5 quadrillion miles) from Earth; this planet was discovered with gravitational microlensing.
2006, OGLE-2005-BLG-390Lb
On January 25, the discovery of OGLE-2005-BLG-390Lb was announced. This is the most distant and probably the coldest exoplanet found to date. It is believed that it orbits a red dwarf star around 21,500 light years from Earth, towards the center of the Milky Way galaxy. It was discovered using gravitational microlensing, and is estimated to have a mass of 5.5 times that of Earth, making it the least massive known exoplanet to orbit an ordinary main-sequence star. Prior to this discovery, the few known exoplanets with comparably low masses had only been discovered on orbits very close to their parent stars, but this planet is estimated to have a relatively wide separation of 2.6 AU from its parent star.[37][38]
2006, HD 69830
A planetary system with three Neptune-mass planets. It is the first triple planetary system around a Sun-like star without any Jupiter-like planets. All three planets were announced on May 18 by Lovis. All three orbit within 1 AU. The planets b, c, d have masses of 10, 12, and 18 Earths respectively. The outermost planet d appears to be in the habitable zone, sheparding the asteroid belt.[39]
2007, HD 209458 b and HD 189733 b
On February 21, 2007, NASA and Nature released news that HD 209458 b and HD 189733 b were the first two extrasolar planets to have their spectra directly observed.[40][41] This was long seen as the first mechanism by which extrasolar but non-intelligent life forms could be searched for, by way of influence on a planet's atmosphere. A group of investigators led by Dr. Jeremy Richardson of NASA's Goddard Space Flight Center were first to publication, in the February 22 issue of Nature. Richardson et al. spectrally measured HD 209458 b's atmosphere in the range of 7.5 to 13.2 micrometres. The results defied theoretical expectations in several ways. The spectrum had been predicted to have a peak at 10 micrometres which would have indicated water vapor in the atmosphere, but such a peak was absent, indicating no detectable water vapor. Another, unpredicted peak was observed at 9.65 micrometres, which the investigators attributed to clouds of silicate dust, a phenomenon not previously observed. Another unpredicted peak occurred at 7.78 micrometres, which the investigators did not have an explanation for. A separate team led by Mark Swain of the Jet Propulsion Laboratory also separately analyzed the Richardson team's data and indicated that their findings were similar. They had submitted their results to Astrophysical Journal Letters. A team led by Carl Grillmair of NASA's Spitzer Science Center made the observations of HD 189733 b, and their results were pending publication in Astrophysical Journal Letters at the time of the news release. On July 11, 2007, the findings by the Spitzer Science Center were published in the Nature: Spectral imprints of water vapor were found by the Spitzer Space Telescope, thus representing the first solid evidence of water on an extrasolar planet.[42]
Artist's Impression of Gliese 581 c
Artist's Impression of Gliese 581 c
2007, Gliese 581 c
Announced on Space.com on April 24, 2007, at 4:23pm ET, it has been determined that this exoplanet could support liquid water and possibly life.[43] While evidence of liquid water has not been detected, the position of this planet—being in a position that might be within the host star's habitable zone—would allow for water to exist in its liquid state. Seth Shostak, a senior astronomer with the SETI institute, stated that on two previous occasions, Gliese 581 was looked at as a potential candidate for extraterrestrial intelligence, but both examinations revealed no proof. The confirmation of the exoplanet's position was determined using the HARPS instrument on the European Southern Observatory's 3.6 meter telescope, by applying the radial velocity detection method. Gliese 581 c is estimated to be fifty percent larger than Earth and close to five times Earth's mass. Some researchers argue that Gliese 581 c will have a runaway greenhouse effect, and thus would not be habitable.[44] They argue, however, that Gliese 581 d is near the outer edge of the Habitable zone.
2007, Gliese 436 b 
This planet was one of the first Neptune-mass planet discovered in August 2004. In May 2007, a transit was found, which make it the least massive transiting planet as of yet. Spectral studies found that this planet contains exotic form of solid water called "hot ice," which exists, despite the planet's high temperatures, because the planet's gravity causes water to be extremely dense. Data indicates that it is a rocky and watery planet with a mass 22 times that of Earth.[45]
2007, XO-3b 
A 13.24 Jupiter-mass planet is the most massive transiting planet ever found, and most massive extrasolar planet found to date, just above the brown dwarf limit at 13.00 MJ. The planet would have radius of 1.92 times Jupiter, the largest of any known extrasolar planets. The planet takes only 3.19 days to orbit the star. The orbit has an unusually high eccentricity (0.22) for such a short period planet.[46]
2007, TrES-4 
The largest-diameter and lowest-density exoplanet to date, TrES-4 is 1.7 times Jupiter's diameter but only 0.84 times its mass, giving it a density of just 0.2 grams per cubic centimeter — about the same as balsa wood. It orbits its primary closely and is therefore quite hot, but stellar heating alone does not appear to explain its large size.[47]
2008, OGLE-2006-BLG-109Lb and OGLE-2006-BLG-109Lc
On February 14 the discovery of the, until now, most similar Jupiter-Saturn planetary system constellation was announced, with the ratios of mass, distance to their star and orbiting time similar to that of Jupiter-Saturn. This can be important for possible life in a solar system as Jupiter and Saturn have a stabilizing effect to the habitable zone by sweeping away large asteroids from the habitable zone.[48]
2008, HD 189733 b
On March 20 follow up studies to the first spectral analyses of an extrasolar planet were published in the scientific journal Nature, announcing evidence of an organic molecule was found on an extrasolar planet for the first time. In 2007 water vapor was already detected in the spectrum of HD 189733 b, but new analyses showed not only water vapor, but also methane existing in the atmosphere of the giant gas planet. Although conditions on HD 189733 b are too harsh to harbor life, it still is the first time a key molecule for organic life was found on an extrasolar planet.[49]
2008, Gliese 436 c
On April 9 Ribas published the smallest exoplanet discovered yet (although it is only the smallest exoplanet discovered around a main-sequence star, with the three exoplanets around the pulsar PSR B1257+12 being the smallest exoplanets discovered to date), its radius is only 50% greater than Earth and 5 times as massive. It was discovered by analyzing anomalies in Gliese 436 b. Its orbit is 5 days while its rotation is 22 days.[50]

47 Ursae Majoris b is an extrasolar planet orbiting the Sun-like star 47 Ursae Majoris. ... Gliese 876 b is an extrasolar planet orbiting the red dwarf star Gliese 876 every 60. ... This article is about the British sitcom. ... Gliese 876 is a red dwarf star located approximately 15 light-years away in the constellation Aquarius. ... This article is about the planet. ... Sol redirects here. ... Upsilon Andromedae (Ï… And ) is a star, approximately 44 light-years from Earth, and approximately 3 billion years old, two thirds the age of our Sun. ... Hertzsprung-Russell diagram The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. ... Upsilon Andromedae b (occasionally referred to as Upsilon Andromedae Ab to distinguish it from the red dwarf star Upsilon Andromedae B) is an extrasolar planet orbiting the Sun-like star Upsilon Andromedae A every 4. ... Upsilon Andromedae c is an extrasolar planet orbiting the Sun-like star Upsilon Andromedae A every 241. ... Upsilon Andromedae d is an extrasolar planet orbiting the Sun-like star Upsilon Andromedae A. Its discovery in 1999 by Geoffrey Marcy and R. Paul Butler made Upsilon Andromedae the first known star (other than the pulsar PSR 1257+12) to host a multiple-planet planetary system. ... HD 209458 b is an extrasolar planet that orbits the Sun-like star HD 209458 in the constellation Pegasus, some 150 light-years from Earths solar system, with evidence of water vapor. ... HD 209458 b is an extrasolar planet that orbits the Sun-like star HD 209458 in the constellation Pegasus, some 150 light-years from Earths solar system, with evidence of water vapor. ... The Hubble Space Telescope (HST; also known colloquially as the Hubble or just Hubble) is a space telescope that was carried into Earth orbit by the Space Shuttle in April 1990. ... For sodium in the diet, see Salt. ... Iota Draconis b was discovered in 2001 during a radial velocity study of K-class giant stars and was the first planet discovered orbiting a giant star. ... Giant star is a star that has stopped fusing hydrogen in its core. ... A giant star is a star with substantially larger radius and luminosity than a main sequence star of the same surface temperature. ... An artists concept of a planetary system A planetary system consists of the various non-stellar objects orbiting a star such as planets, moons, asteroids, meteoroids, comets, and cosmic dust. ... Angular frequency is a measure of how fast an object is rotating In physics (specifically mechanics and electrical engineering), angular frequency ω (also called angular speed) is a scalar measure of rotation rate. ... Image File history File links Artists_impression_of_pulsar_planet_B1620-26c. ... Image File history File links Artists_impression_of_pulsar_planet_B1620-26c. ... It has been suggested that Radio pulsar be merged into this article or section. ... An artists impression of the view from near the planet PSR B1620-26c is a planet orbiting the pulsar PSR B1620-26 in the globular cluster Messier 4, about 12,400 light years from Earth in the constellation of Scorpius. ... An artists impression of the view from near the planet PSR B1620-26c is a planet orbiting the pulsar PSR B1620-26 in the globular cluster Messier 4, about 12,400 light years from Earth in the constellation of Scorpius. ... is the 191st day of the year (192nd in leap years) in the Gregorian calendar. ... The Hubble Space Telescope (HST; also known colloquially as the Hubble or just Hubble) is a space telescope that was carried into Earth orbit by the Space Shuttle in April 1990. ... This article or section does not cite its references or sources. ... Globular Cluster M4 (also known as Messier Object 4, Messier 4, M4, or NGC 6121) is a globular cluster in the Scorpius constellation. ... This article is about the star grouping. ... This article is about the constellation. ... For the band of the same name, see: Binary Star (band) Hubble image of the Sirius binary system, in which Sirius B can be clearly distinguished (lower left). ... It has been suggested that Radio pulsar be merged into this article or section. ... This article or section does not adequately cite its references or sources. ... Mu Arae d at the time of its discovery was the least massive extrasolar planet found around a main sequence star. ... Mu Arae (μ Ara / μ Arae) is a Sunlike yellow-orange star located around 50 light years away in the constellation Ara. ... The European Southern Observatory (ESO) is an international astronomical organisation, composed and supported by ten countries from the European Union plus Switzerland. ... The High Accuracy Radial velocity Planet Searcher (HARPS) is a high-precision echelle spectrograph installed in 2002 with first light achieved February 2003 on ESOs 3. ... For Acoustic uses in spectrographs of sound waves, see below. ... Image File history File links Phot-14a-05-preview. ... Image File history File links Phot-14a-05-preview. ... A second of arc or arcsecond is a unit of angular measurement which comprises one-sixtieth of an arcminute, or 1/3600 of a degree of arc or 1/1296000 ≈ 7. ... The European Southern Observatory (ESO) is an international astronomical organisation, composed and supported by ten countries from the European Union plus Switzerland. ... One of the four telescopes that make up the VLT, named Kueyen. ... 2M1207 b is a gas giant exoplanet orbiting the brown dwarf 2M1207. ... This brown dwarf (smaller object) orbits the star Gliese 229, which is located in the constellation Lepus about 19 light years from Earth. ... For other uses, see Infrared (disambiguation). ... The astronomical unit (AU or au or a. ... For other uses, see Jupiter (disambiguation). ... This article does not cite any references or sources. ... A protoplanetary disc (also protoplanetary disk, proplyd) is an accretion disc surrounding a T Tauri star. ... Gliese 876 d is an extrasolar planet orbiting the red dwarf star Gliese 876. ... This article is about the British sitcom. ... Gliese 876 is a red dwarf star located approximately 15 light-years away in the constellation Aquarius. ... The astronomical unit (AU or au or a. ... HD 149026 b, is a transiting extrasolar planet orbiting the star HD 149026. ... HD 149026 b, is a transiting extrasolar planet orbiting the star HD 149026. ... HD 75289 is an 8th magnitude star in constellation Hercules. ... Image File history File linksMetadata Download high resolution version (1280x960, 575 KB) Summary Planet OGLE-2005-BLG-390Lb discovered by OGLE project in 2005. ... Image File history File linksMetadata Download high resolution version (1280x960, 575 KB) Summary Planet OGLE-2005-BLG-390Lb discovered by OGLE project in 2005. ... OGLE-2005-BLG-390Lb is a super-Earth extrasolar planet orbiting the star OGLE-2005-BLG-390L, which is situated 21,500 ± 3,300 light years away from Earth, near the center of the Milky Way galaxy. ... A light year, abbreviated ly, is the distance light travels in one year: roughly 9. ... This article is about Earth as a planet. ... OGLE-2005-BLG-390Lb is a super-Earth extrasolar planet orbiting the star OGLE-2005-BLG-390L, which is situated 21,500 ± 3,300 light years away from Earth, near the center of the Milky Way galaxy. ... is the 25th day of the year in the Gregorian calendar. ... For other uses, see Milky Way (disambiguation). ... HD 69830 is an orange dwarf star. ... An artists concept of a planetary system A planetary system consists of the various non-stellar objects orbiting a star such as planets, moons, asteroids, meteoroids, comets, and cosmic dust. ... For other uses, see Neptune (disambiguation). ... is the 138th day of the year (139th in leap years) in the Gregorian calendar. ... HD 69830 b is a Neptune-mass or Super-Earth mass extrasolar planet orbits the star HD 69830. ... HD 69830 c is the 2nd planet orbiting HD 69830. ... HD 69830 d is an extrasolar planet orbiting the orange dwarf star HD 69830 every 197 days. ... For other uses, see Asteroid (disambiguation). ... HD 209458 b is an extrasolar planet that orbits the Sun-like star HD 209458 in the constellation Pegasus, some 150 light-years from Earths solar system, with evidence of water vapor. ... HD 189733 b is a gas giant planet that is in very close orbit around the yellow dwarf star HD 189733 A. This planet was discovered in 2005 when astronomers observed the planet transiting across the face of the star. ... is the 52nd day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... For other uses, see NASA (disambiguation). ... Nature is a prominent scientific journal, first published on 4 November 1869. ... Aerial view of Goddard Space Flight Center. ... For the singer/songwriter, see Jon Peter Lewis. ... The California Institute of Technology (commonly referred to as Caltech)[1] is a private, coeducational university located in Pasadena, California, in the United States. ... is the 192nd day of the year (193rd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... The Spitzer Space Telescope (formerly the Space Infrared Telescope Facility [SIRTF]) is an infrared space observatory, the fourth and final of NASAs Great Observatories. ... Image File history File linksMetadata No higher resolution available. ... Image File history File linksMetadata No higher resolution available. ... Gliese 581 c (IPA: ) is a super-earth extrasolar planet orbiting the red dwarf star Gliese 581. ... Gliese 581 c (IPA: ) is a super-earth extrasolar planet orbiting the red dwarf star Gliese 581. ... Space. ... is the 114th day of the year (115th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... It has been suggested that Goldilocks phenomenon be merged into this article or section. ... Seth Shostak. ... Extraterrestrial life refers to forms of life that may exist and originate outside of the planet Earth. ... The High Accuracy Radial velocity Planet Searcher (HARPS) is a high-precision echelle spectrograph installed in 2002 with first light achieved February 2003 on ESOs 3. ... The European Southern Observatory (ESO) is an international astronomical organisation, composed and supported by ten countries from the European Union plus Switzerland. ... Any planet is an extremely faint light source compared to its parent star. ... This article is about Earth as a planet. ... Gliese 581 d is an extrasolar planet orbiting the red dwarf star Gliese 581. ... Gliese 436 b (IPA: ) (GJ 436 b)[1] is a Neptune-sized extrasolar planet orbiting the red dwarf star Gliese 436. ... For other uses, see Neptune (disambiguation). ... XO-3b is an exoplanet with more then thirteen times the mass of Jupiter, and an orbit around its parent star of less then four days. ... This brown dwarf (smaller object) orbits the star Gliese 229, which is located in the constellation Lepus about 19 light years from Earth. ... TrES-4 is an exoplanet discovered in 2006[2] by the Trans-Atlantic Exoplanet Survey using the transit method. ... Binomial name Ochroma lagopus Balsa (Ochroma lagopus, synonym ) is a large, fast-growing tree to 30 m tall, native from tropical South America north to southern Mexico. ... is the 45th day of the year in the Gregorian calendar. ... For other uses, see Jupiter (disambiguation). ... This article is about the planet. ... This article is about life in general. ... This article is about the Solar System. ... It has been suggested that Goldilocks phenomenon be merged into this article or section. ... For other uses, see Asteroid (disambiguation). ... HD 189733 b is a gas giant planet that is in very close orbit around the yellow dwarf star HD 189733 A. This planet was discovered in 2005 when astronomers observed the planet transiting across the face of the star. ... is the 79th day of the year (80th in leap years) in the Gregorian calendar. ... Nature is a prominent scientific journal, first published on 4 November 1869. ... HD 189733 b is a gas giant planet that is in very close orbit around the yellow dwarf star HD 189733 A. This planet was discovered in 2005 when astronomers observed the planet transiting across the face of the star. ... is the 99th day of the year (100th in leap years) in the Gregorian calendar. ... Hertzsprung-Russell diagram The main sequence of the Hertzsprung-Russell diagram is the curve along which the majority of stars are located. ... It has been suggested that Radio pulsar be merged into this article or section. ... PSR B1257+12 (sometimes abbreviated to PSR 1257+12) is a pulsar located 980 light years from Earth. ...

Discovery firsts

Title Planet Star Year Notes
First planet discovered PSR B1257+12 B, C PSR B1257+12 1992 first extrasolar planets discovered
Note 1: The planet around Gamma Cephei was already suspected in 1988.
Note 2: HD 114762 b was discovered in 1989, but was not confirmed as a planet before 1996.
First discovery by a method
First planet discovered using the pulsar timing method PSR B1257+12 B, C PSR B1257+12 1992
First planet discovered by radial velocity method 51 Pegasi b 51 Pegasi 1995
First planet discovered by transit method OGLE-TR-56 b OGLE-TR-56 2002
NOTE: The first discovered transiting planet was HD 209458 b, which had already been discovered.
First planet found by gravitational lensing method OGLE-2003-BLG-235Lb OGLE-2003-BLG-235L/MOA-2003-BLG-53L 2004
First discovery by system type
First planet around a solitary star PSR B1257+12 B, C PSR B1257+12 1992 first extrasolar planets discovered
Note 1: HD 114762 b was discovered in 1989, but was not confirmed as a planet before 1996.
First free-floating planet discovered S Ori 70 n/a 2004 has mass of 3 MJupiter, needs confirmation
Note: Free-floating objects are not usually considered planets.
First planet in a multiple star system discovered 55 Cancri b 55 Cancri 1996 55 Cnc has distant red dwarf companion
Note 1: The planet around Gamma Cephei was already suspected in 1988.
Note 2: Gamma Cephei is the first relatively close binary with a planet.
First planet orbiting multiple stars discovered PSR B1620-26c PSR B1620-26 1993 orbits pulsar - white dwarf pair
First multiple planet system discovered PSR 1257+12 A, B, C PSR 1257+12 1992 a pulsar planetary system
First planet in star cluster PSR B1620-26c PSR B1620-26 1993 located in Globular Cluster M4
First discovery by star type
First pulsar planet discovered PSR B1257+12 B, C PSR B1257+12 1992
First known planet orbiting a Sun-like star 51 Pegasi b 51 Pegasi 1995
First known planet orbiting a red dwarf Gliese 876 b Gliese 876 1998
First known planet orbiting a giant star Iota Draconis b Iota Draconis 2002
First known planet orbiting a white dwarf (confirmed 2003) PSR B1620-26c PSR B1620-26 1993 in December 2007, GD 66 b was discovered orbiting a solitary white dwarf star GD 66
First known planet orbiting a brown dwarf 2M1207b 2M1207 2004 first directly imaged planet
First free-floating planet discovered S Ori 70 n/a 2004 has mass of 3 MJupiter, needs confirmation
Note: Free-floating objects are not usually considered planets.
Firsts by planet type
first cool, possibly rocky/icy planet around main-sequence star OGLE-2005-BLG-390Lb OGLE-2005-BLG-390L 2006
Other firsts
First transiting planet HD 209458 b HD 209458 1999
Note: OGLE-TR-56 b is the first planet found by transit method.
First directly imaged planet 2M1207b 2M1207 2004 first planet found around brown dwarf

PSR B1257+12 (sometimes abbreviated to PSR 1257+12) is a pulsar located 980 light years from Earth. ... PSR B1257+12 (sometimes abbreviated to PSR 1257+12) is a pulsar located 980 light years from Earth. ... Gamma Cephei (γ Cep / γ Cephei) is a star in the constellation Cepheus. ... HD 114762 is a yellow main sequence star. ... PSR B1257+12 (sometimes abbreviated to PSR 1257+12) is a pulsar located 980 light years from Earth. ... PSR B1257+12 (sometimes abbreviated to PSR 1257+12) is a pulsar located 980 light years from Earth. ... Radial velocity is the velocity of an object in the direction of the line of sight. ... 51 Pegasi b (also written as 51 Peg b) is the first planet discovered around a sun-like star outside of the solar system. ... 51 Pegasi (Flamsteed designation, HIP 113357 in the Hipparcos Catalogue, HD 217014 in the Henry Draper Catalogue) is the name of a Sun-like star 14. ... Deimos transits the Sun, as seen by Mars Rover Opportunity on March 4, 2004 The word transit has two meanings in astronomy: A transit is the astronomical event that occurs when one celestial body appears to move across the face of another celestial body, as seen by an observer at... OGLE-TR-56 is a star in the constellation Sagittarius. ... OGLE-TR-56 is a star in the constellation Sagittarius. ... HD 209458 b is an extrasolar planet that orbits the Sun-like star HD 209458 in the constellation Pegasus, some 150 light-years from Earths solar system, with evidence of water vapor. ... This article or section is in need of attention from an expert on the subject. ... OGLE-2003-BLG-235/MOA 2003-BLG-53 was a gravitational microlensing event which occurred in the constellation of Sagittarius during July 2003. ... OGLE-2003-BLG-235/MOA 2003-BLG-53 was a gravitational microlensing event which occurred in the constellation of Sagittarius during July 2003. ... PSR B1257+12 (sometimes abbreviated to PSR 1257+12) is a pulsar located 980 light years from Earth. ... PSR B1257+12 (sometimes abbreviated to PSR 1257+12) is a pulsar located 980 light years from Earth. ... HD 114762 is a yellow main sequence star. ... 55 Cancri (abbreviated 55 Cnc; Bayer designation ρ1 Cancri, Rho-1 Cancri) is a nearby 6th magnitude star in the constellation Cancer. ... 55 Cancri (abbreviated 55 Cnc; Bayer designation ρ1 Cancri, Rho-1 Cancri) is a nearby 6th magnitude star in the constellation Cancer. ... Gamma Cephei (γ Cep / γ Cephei) is a star in the constellation Cepheus. ... Gamma Cephei (γ Cep / γ Cephei) is a star in the constellation Cepheus. ... An artists impression of the view from near the planet PSR B1620-26c is a planet orbiting the pulsar PSR B1620-26 in the globular cluster Messier 4, about 12,400 light years from Earth in the constellation of Scorpius. ... It has been suggested that Radio pulsar be merged into this article or section. ... An artists conception of PSR 1257+12s system of planets Pulsars are rapidly rotating neutron stars. ... An artists concept of a planetary system A planetary system consists of the various non-stellar objects orbiting a star such as planets, moons, asteroids, meteoroids, comets, and cosmic dust. ... Globular Cluster M4 (also known as Messier Object 4, Messier 4, M4, or NGC 6121) is a globular cluster in the Scorpius constellation. ... An artists conception of PSR 1257+12s system of planets Pulsars are rapidly rotating neutron stars. ... PSR B1257+12 (sometimes abbreviated to PSR 1257+12) is a pulsar located 980 light years from Earth. ... PSR B1257+12 (sometimes abbreviated to PSR 1257+12) is a pulsar located 980 light years from Earth. ... Hertzsprung-Russell diagram The main sequence of the Hertzsprung-Russell diagram is the curve where the majority of stars are located in this diagram. ... 51 Pegasi b (also written as 51 Peg b) is the first planet discovered around a sun-like star outside of the solar system. ... 51 Pegasi (Flamsteed designation, HIP 113357 in the Hipparcos Catalogue, HD 217014 in the Henry Draper Catalogue) is the name of a Sun-like star 14. ... This article is about the British sitcom. ... Gliese 876 is a red dwarf star located approximately 15 light-years away in the constellation Aquarius. ... Gliese 876 is a red dwarf star located approximately 15 light-years away in the constellation Aquarius. ... Giant star is a star that has stopped fusing hydrogen in its core. ... Iota Draconis b was discovered in 2001 during a radial velocity study of K-class giant stars and was the first planet discovered orbiting a giant star. ... Edasich (Hyaene) is the name of the star? Draconis (Iota Draconis). ... This article or section does not adequately cite its references or sources. ... An artists impression of the view from near the planet PSR B1620-26c is a planet orbiting the pulsar PSR B1620-26 in the globular cluster Messier 4, about 12,400 light years from Earth in the constellation of Scorpius. ... PSR B1620-26 is also called PSR J1623-2631 (or or ) // System Configuration PSR B1620-26 is a pulsar in the globular cluster Messier 4 (or M4: see Messier object), about 5,600 light years from Earth in the constellation Scorpius. ... This brown dwarf (smaller object) orbits the star Gliese 229, which is located in the constellation Lepus about 19 light years from Earth. ... 2M1207b is an extrasolar planet orbiting the brown dwarf 2M1207, a star in the constellation Hydra approximately 200 light years from Earth. ... 2M1207, 2M1207A or 2MASSW J1207334-393254 is a brown dwarf star located in the constellation Hydra; a companion object, 2M1207b, is believed to be one of the first extrasolar planets to be directly imaged, and is the first exoplanet to be discovered in orbit of a brown dwarf. ... OGLE-2005-BLG-390Lb is a super-Earth extrasolar planet orbiting the star OGLE-2005-BLG-390L, which is situated 21,500 ± 3,300 light years away from Earth, near the center of the Milky Way galaxy. ... OGLE-2005-BLG-390Ls location in the night sky OGLE-2005-BLG-390L is a star thought to be a spectral type M - red dwarf star (95% probability, 4% probability it is a white dwarf, <1% probability it is a neutron star or black hole), and massing 0. ... Deimos transits the Sun, as seen by Mars Rover Opportunity on March 4, 2004 The word transit has two meanings in astronomy: A transit is the astronomical event that occurs when one celestial body appears to move across the face of another celestial body, as seen by an observer at... HD 209458 b is an extrasolar planet that orbits the Sun-like star HD 209458 in the constellation Pegasus, some 150 light-years from Earths solar system, with evidence of water vapor. ... HD 209458 is an 8th magnitude star in the constellation Pegasus. ... 2M1207b is an extrasolar planet orbiting the brown dwarf 2M1207, a star in the constellation Hydra approximately 200 light years from Earth. ... 2M1207, 2M1207A or 2MASSW J1207334-393254 is a brown dwarf star located in the constellation Hydra; a companion object, 2M1207b, is believed to be one of the first extrasolar planets to be directly imaged, and is the first exoplanet to be discovered in orbit of a brown dwarf. ...

See also

Wikimedia Commons has media related to:
Exoplanets

Image File history File links Commons-logo. ... Image File history File links En-Extrasolar_planet. ... Image File history File links Sound-icon. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 340th day of the year (341st in leap years) in the Gregorian calendar. ... Image File history File links This is a lossless scalable vector image. ... Wikiversity logo Wikiversity is a Wikimedia Foundation beta project[1], devoted to learning materials and activities, located at www. ...

Classification

The appearance of extrasolar planets is largely unknown because of the difficulty in making direct observations of extrasolar planets. ... An artists conception of PSR 1257+12s system of planets Pulsars are rapidly rotating neutron stars. ... Gliese 581 c, a super-Earth and its star as rendered in Celestia. ... Artists impression of roaster extrasolar planet HD 209458b (Osiris). ... An Eccentric Jupiter is a Jovian planet that orbits its star in a highly eccentric orbit, much like a comet. ... This article does not cite any references or sources. ... The inner planets, Mercury, Venus, Earth, and Mars, their sizes to scale. ... A Chthonian planet (sometimes misspelled Cthonian), is a gas giant with its hydrogen and helium atmosphere stripped away due to its closeness to its star. ... Ocean planets are an as-yet hypothetical type of planet whose surface is completely covered with an ocean of water. ... This article is about science fiction. ...

System

For the band of the same name, see: Binary Star (band) Hubble image of the Sirius binary system, in which Sirius B can be clearly distinguished (lower left). ... An artists rendering of a hypothetical exoplanet. ... An interstellar planet is a hypothetical type of rogue planet that has been ejected from its solar system by a proto-gas giant to become an outcast, drifting in interstellar space. ... An artists concept of a planetary system A planetary system consists of the various non-stellar objects orbiting a star such as planets, moons, asteroids, meteoroids, comets, and cosmic dust. ... The term Extrasolar moon refers to a natural (non-man-made) satellite that orbits an extrasolar planet or other extrasolar body larger than itself. ...

Observatories

Any planet is an extremely faint light source compared to its parent star. ... The Geneva Extrasolar Planet Search is a variety of observational programs run by M. Mayor, D. Naef, F. Pepe, D. Queloz, N.C. Santos, and S. Udry. ... The Anglo-Australian Observatory (AAO) is an optical astronomy observatory with its headquarters in suburban Sydney, Australia. ... The California and Carnegie Planet Search was started as the San Francisco State University Planet Search in 1987 by Geoffrey Marcy and R. Paul Butler. ... Infrared image of 2M1207 (blue) and its planet 2M1207b, as viewed by the Very Large Telescope. ... The Hungarian Automated Telescope Network (HATNet) project is a network of six small fully-automated HAT telescopes. ... The Trans-Atlantic Exoplanet Survey or TrES, uses three 4-inch (10cm) telescopes located at Lowell Observatory, Mount Palomar, and the Canary Islands to locate exoplanets. ... SuperWASP consists of two camera arrays, one in the Northern Hemisphere at Roque de los Muchachos Observatory, and one in the Southern Hemisphere at the South African Astronomical Observatory designed to search for extrasolar planets. ... The XO Telescope is a telescope formed by a pair of 200mm telephoto lenses. ... The Optical Gravitational Lensing Experiment (OGLE) survey. ...

Missions

For a French painter, see Jean-Baptiste-Camille Corot. ... This article is about the European Space Agency. ... The Kepler Mission is a space observatory being developed by NASA that will search for extrasolar planets and will only be the second space-based telescope particularly constructed for that task, the first one being COROT. For this purpose, it will observe the brightness of about 100,000 stars over... PEGASE is a proposed space mission to build a double-aperture interferometer composed of three free-flying satellites. ... Artists concept of Space Interferometry Mission spacecraft The Space Interferometry Mission (SIM), also called SIM PlanetQuest, is a NASA instrument originally expected to be launched in December of 2011; however due to budget cuts it will now launch no sooner than between October 2014 and April 2015. ... This article does not cite any references or sources. ... Terrestrial Planet Finder - Infrared interferometer concept The Terrestrial Planet Finder (TPF) is a plan by NASA for a telescope system that would be capable of detecting extrasolar terrestrial planets. ... Darwin is a proposed European Space Agency (ESA) mission designed to directly detect Earth-like planets orbiting nearby stars, and search for evidence of life on these planets. ...

Astronomers

  • Geoffrey Marcy — co-discoverer with R. Paul Butler of more exoplanets than anyone else
  • R. Paul Butler — co-discoverer with Geoffrey Marcy of more exoplanets than anyone else
  • Debra Fischer — co-discoverer with Geoffrey Marcy and R. Paul Butler of more exoplanets than anyone else
  • Aleksander Wolszczan — co-discoverer of PSR B1257+12 B and C, the first ever discovered exoplanets, with Dale Frail
  • Dale Frail — co-discoverer of PSR B1257+12 B and C, the first ever discovered exoplanets, with Aleksander Wolszczan
  • Michel Mayor — co-discoverer of 51 Pegasi b, the first ever discovered exoplanet orbiting a Sun-like star, with Didier Queloz
  • Didier Queloz — co-discoverer of 51 Pegasi b, the first ever discovered exoplanet orbiting a Sun-like star, with Michel Mayor
  • Stephane Udry — co-discoverer of Gliese 581 c, the most Earth-like planet

Image:Geoff marcy. ... Paul Butler is an astronomer who searches for extrasolar planets. ... Professor Fischer showing off her pgplot prowess with a keplerian fit for υ And. ... Aleksander Wolszczan (b. ... PSR B1257+12 (sometimes abbreviated to PSR 1257+12) is a pulsar located 980 light years from Earth. ... Dale Frail is an astronomer. ... PSR B1257+12 (sometimes abbreviated to PSR 1257+12) is a pulsar located 980 light years from Earth. ... Michel Mayor (born 12 January 1942) is a professor in the Department of Astronomy at the University of Geneva. ... 51 Pegasi b (also written as 51 Peg b) is the first planet discovered around a sun-like star outside of the solar system. ... Didier Queloz, born 23 February 1966, is a Geneva-based astronomer with a prolific record in finding extrasolar planets. ... 51 Pegasi b (also written as 51 Peg b) is the first planet discovered around a sun-like star outside of the solar system. ... Stéphane Udry (*1961 in Sion, Switzerland) is an astronomer at the University of Geneva in Switzerland, whose current work is primarily the search for extra-solar planets. ... Gliese 581 c (IPA: ) is a super-earth extrasolar planet orbiting the red dwarf star Gliese 581. ...

Books

Distant Wanderers: The Search for Planets Beyond the Solar System is a book, written by journalist Bruce Dorminey, which reports on astronomical research and theory related to the search for extrasolar planets. ...

Lists

For a list of brown dwarfs, including those orbiting stars, see list of brown dwarfs. ... The following are lists of extremes among the known extrasolar planets. ... This is a list of unconfirmed extrasolar planets. ...

Habitability

Understanding planetary habitability is partly an extrapolation of the Earths conditions, as it is the only planet currently known to support life. ... Green people redirects here. ... Extraterrestrial liquid water, the presence of water in its liquid state, is a subject of wide interest because it is a commonly suggested prerequisite for the emergence of extraterrestrial life. ...

References

  1. ^ a b c Schneider, Jean (2007-04-25). Interactive Extra-solar Planets Catalog. The Extrasolar Planets Encyclopedia. Retrieved on 2007-08-09.
  2. ^ a b c d Marcy, G.; Butler, R.; Fischer, D.; et.al. (2005). "Observed Properties of Exoplanets: Masses, Orbits and Metallicities". Progress of Theoretical Physics Supplement 158: 24 – 42. 
  3. ^ Terrestrial Planet Finder science goals: Detecting signs of life. JPL Terrestrial Planet Finder website. Retrieved on 2006-07-21.
  4. ^ Jacob, W.S. (1855). "On Certain Anomalies presented by the Binary Star 70 Ophiuchi". Monthly Notices of the Royal Astronomical Society 15: 228. 
  5. ^ See, Thomas Jefferson Jackson (1896). "Researches on the Orbit of F.70 Ophiuchi, and on a Periodic Perturbation in the Motion of the System Arising from the Action of an Unseen Body". The Astronomical Journal 16: 17. 
  6. ^ Sherrill, Thomas J. (1999). "A Career of controversy: the anomaly OF T. J. J. See". Journal for the history of astronomy 30. Retrieved on 2007-08-27. 
  7. ^ van de Kamp, Peter (August 1969). "Alternate dynamical analysis of Barnard's star". The Astronomical Journal 74: 757-759. Retrieved on 2007-08-27. 
  8. ^ Bailes, M.; Lyne, A.G.; Shemar, S.L. (1991). "A planet orbiting the neutron star PSR1829-10". Nature 352: 311 – 313. 
  9. ^ Lyne, A.G.; Bailes, M. (1992). "No planet orbiting PS R1829-10". Nature 355 (6357): 213. 
  10. ^ Campbell, B.; Walker, G. A. H.; Yang, S. (1988). "A search for substellar companions to solar-type stars". Astrophysical Journal, Part 1 331: 902 – 921. 
  11. ^ Lawton, A. T.; Wright, P. (1989). "A planetary system for Gamma Cephei?". British Interplanetary Society, Journal 42: 335 – 336. 
  12. ^ Walker, G. A. H.; Bohlender, D. A.; Walker, A. R.; Irwin, A. W.; Yang, S. L. S.; Larson, A. (1992). "Gamma Cephei - Rotation or planetary companion?". Astrophysical Journal, Part 2 - Letters 396 (2): L91 – L94. 
  13. ^ Hatzes et al. (2003). "A Planetary Companion to Gamma Cephei A". The Astrophysical Journal 599 (2): 1383 – 1394. 
  14. ^ a b Wolszczan, A.; Frail, D. A. (1992). "A planetary system around the millisecond pulsar PSR1257+12". Nature 355: 145 – 147. 
  15. ^ a b Mayor, Michel; Queloz, Didier (1995). "A Jupiter-mass companion to a solar-type star". Nature 378: 355 – 359. 
  16. ^ An especially simple and inexpensive method for measuring radial velocity is “externally dispersed interferometry.” See the following Web site: http://www.spectralfringe.org/EDI/ . See also: Erskine, Edelstein, Harbeck and Lloyd, “Externally dispersed interferometry for planetary studies,” in Techniques and Instrumentation for Detection of Exoplanets II, Daniel R. Coulter, ed., Proceedings of the SPIE *, vol. 5905, pages 249-260 (2005). Available on-line at: https://e-reports-ext.llnl.gov/pdf/322047.PDF . (* SPIE = Society of Photo-optical Instrumentation Engineers; renamed: International Society for Optical Engineering)
  17. ^ "A neighbor: Gliese 581 c (planet Ymir)", April 2007. Retrieved on 2007-08-09. 
  18. ^ http://www.iau.org/PLANETS_AROUND_OTHER_STARS.247.0.html Planets Around Other Stars. Retrieved on 12/8/06.
  19. ^ Working Group on Extrasolar Planets: Definition of a "Planet". IAU position statement (February 28, 2003). Retrieved on 2006-09-09.
  20. ^ Why Planets Will Never Be Defined (2006). Retrieved on 2008-02-13.
  21. ^ Bonfils, X.; Forveille, T.; Delfosse, X.; et.al. (2005). "The HARPS search for southern extra-solar planets VI: A Neptune-mass planet around the nearby M dwarf Gl 581". Astronomy & Astrophysics 443: L15 – L18. doi:10.1051/0004-6361:200500193. 
  22. ^ Linda Vu (October 3, 2006). Planets Prefer Safe Neighborhoods. Retrieved on 2007-09-01.
  23. ^ Charbonneau, D.; T. Brown; A. Burrows; G. Laughlin (2006). "When Extrasolar Planets Transit Their Parent Stars". Protostars and Planets V, University of Arizona Press. 
  24. ^ Scientists Snap Images of First Brown Dwarf in Planetary System (News Release). Eberley CoS website (September 18, 2006). Retrieved on 2006-09-28.
  25. ^ "UC Berkeley astronomers find Jupiter-sized planet around nearby star in Big Dipper". Retrieved on 2007-08-26. 
  26. ^ John Nobile Wilford (2001). "New Planet Detected Around a Star 15 Light Years Away". The New York Times. 
  27. ^ Blake Edgar, Megan Watzke, Carol Rasmussen (1999). "Multiple planets discovered around Upsilon Andromedae". Extrasolar planets 415, 617, 303: 338 – 6747, 495 – 7463, 497 – 8611. 
  28. ^ Henry et al. (2000). "A Transiting "51 Peg-like" Planet". The Astrophysical Journal Letters 529 (1): L41 – L44. 
  29. ^ Charbonneau et al. (2002). "Detection of an Extrasolar Planet Atmosphere". The Astrophysical Journal 568 (1): 377 – 384. 
  30. ^ Frink et al. (2002). "Discovery of a Substellar Companion to the K2 III Giant Iota Draconis". The Astrophysical Journal 576 (1): 478 – 484. 
  31. ^ Sigurdsson, S.; Richer, H.B.; Hansen, B.M.; Stairs I.H.; Thorsett, S.E. (2003). "A Young White Dwarf Companion to Pulsar B1620-26: Evidence for Early Planet Formation". Science 301 (5630): 193 – 196. 
  32. ^ Fourteen Times the Earth - ESO HARPS Instrument Discovers Smallest Ever Extra-Solar Planet. ESO website. Retrieved on 2006-05-07.
  33. ^ Konacki, M. (2005). "Astronomers Confirm the First Image of a Planet Outside of Our Solar System". ESO. 
  34. ^ R. Jayawardhana, N. Huelamo, E. Mamajek (2006). "The Planetary Mass Companion 2MASS1207-3932 B: Temperature, Mass and Evidence for an Edge-On Disk". American Astronomical Society. }
  35. ^ Rivera et al. (2005). "A 7.5 Me Planet Orbiting the Nearby Star GJ 876". The Astrophysical Journal 634 (1): 625 – 640. 
  36. ^ Sato, B.; Fischer, D.; Henry, G.; Laughlin, G.; Butler, R.; Marcy, G.; Vogt, S.; Bodenheimer, P.; Ida, S.; Toyota, E.; Wolf, A.; Valenti, J.; Boyd, L.; Johnson, J.; Wright, J.; Ammons, M.; Robinson, S.; Strader, J.; McCarthy, C.; Tah, K.; Minniti, D. (2005). "The N2K Consortium II: A Transiting Hot Saturn around HD 149026 with a Large Dense Core". The Astrophysical Journal 633: 465 – 473. 
  37. ^ J.-P. Beaulieu; D.P. Bennett; P. Fouque; A. Williams; M. Dominik; U.G. Jorgensen; D. Kubas; A. Cassan; C. Coutures; J. Greenhill; K. Hill; J. Menzies; P.D. Sackett; M. Albrow; S. Brillant; J.A.R. Caldwell; J.J. Calitz; K.H. Cook; E. Corrales; M. Desort; S. Dieters; D. Dominis; J. Donatowicz; M. Hoffman; S. Kane; J.-B. Marquette; R. Martin; P. Meintjes; K. Pollard; K. Sahu; C. Vinter; J. Wambsganss; K. Woller; K. Horne; I. Steele; D. Bramich; M. Burgdorf; C. Snodgrass; M. Bode; A. Udalski; M. Szymanski; M. Kubiak; T. Wieckowski; G. Pietrzynski; I. Soszynski; O. Szewczyk; L. Wyrzykowski; B. Paczynski (2006). "Discovery of a Cool Planet of 5.5 Earth Masses Through Gravitational Microlensing". Nature 439: 437 – 440. 
  38. ^ Kiwis help discover new planet. One News (Jan 26, 2006). Retrieved on 2006-05-07.
  39. ^ Trio of Neptunes and their belt (May 18, 2006). Retrieved on 2007-06-09.
  40. ^ http://www.spitzer.caltech.edu/Media/releases/ssc2007-04/release.shtml Spitzer.caltech.edu Retrieved on 04-25-07
  41. ^ http://www.nature.com/nature/journal/v445/n7130/abs/nature05636.html Nature.com Retrieved on 04-25-07
  42. ^ 'Clear Signs of Water' on Distant Planet at Space.com
  43. ^ Ker Than (Apr 24, 2007 4:23pm ET). Major Discovery: New Planet Could Harbor Water and Life. Retrieved on 2007-04-24.
  44. ^ The Habitability of Super-Earths in Gliese 581. Retrieved on 2007-05-29.
  45. ^ Fox, Maggie. "Hot "ice" may cover recently discovered planet", 16 May 2007. Retrieved on 2007-12-28. 
  46. ^ Krull et al. (2007-05-30). "XO-3b: A Massive Planet in an Eccentric Orbit Transiting an F5V Star". Retrieved on 2008-01-02. 
  47. ^ "Largest Known Exoplanet Discovered", SPACE.com, Aug 6, 2007. Retrieved on 2007-08-26. 
  48. ^ "Solar System Like Ours Found", SPACE.com, February 14, 2008. Retrieved on 2008-02-19. 
  49. ^ "Key Organic Molecule Detected at Extrasolar Planet", SPACE.com, March 20, 2008. Retrieved on 2008-03-20. 
  50. ^ Reuters

Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 115th day of the year (116th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 221st day of the year (222nd in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 202nd day of the year (203rd in leap years) in the Gregorian calendar. ... Thomas Jefferson Jackson (T. J. J.) See, (1866 to July 4, 1962). ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 239th day of the year (240th in leap years) in the Gregorian calendar. ... Piet van de Kamp (December 26, 1901 – May 18, 1995), known as Peter van de Kamp in the United States, was a Dutch-American astronomer. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 239th day of the year (240th in leap years) in the Gregorian calendar. ... For the story by Larry Niven, see Neutron Star (story). ... The Astrophysical Journal is one of the foremost research journals devoted to recent developments, discoveries, and theories in astronomy and astrophysics. ... It has been suggested that Radio pulsar be merged into this article or section. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 221st day of the year (222nd in leap years) in the Gregorian calendar. ... is the 59th day of the year in the Gregorian calendar. ... Year 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 252nd day of the year (253rd in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 44th day of the year in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 244th day of the year (245th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 271st day of the year (272nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 238th day of the year (239th in leap years) in the Gregorian calendar. ... The Astrophysical Journal is one of the foremost research journals devoted to recent developments, discoveries, and theories in astronomy and astrophysics. ... The Astrophysical Journal is one of the foremost research journals devoted to recent developments, discoveries, and theories in astronomy and astrophysics. ... It has been suggested that Radio pulsar be merged into this article or section. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 127th day of the year (128th in leap years) in the Gregorian calendar. ... The Astrophysical Journal is one of the foremost research journals devoted to recent developments, discoveries, and theories in astronomy and astrophysics. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 127th day of the year (128th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 160th day of the year (161st in leap years) in the Gregorian calendar. ... Space. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 114th day of the year (115th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 149th day of the year (150th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 362nd day of the year (363rd in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 2nd day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era in the 21st century. ... is the 238th day of the year (239th in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... [[Media:Italic text]]{| style=float:right; |- | |- | |} is the 50th day of the year in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... is the 79th day of the year (80th in leap years) in the Gregorian calendar. ...

External links

Search projects
  • University of California Planet Search Project
  • The Geneva Extrasolar Planet Search Programmes
  • PlanetQuest distributed computing project
  • SuperWASP Wide Angle Search for Planets
  • Custer search involves amateur volunteers.
Resources
  • NASA's PlanetQuest
    • PlanetQuest 3D Atlas of extrasolar planets within 400 light years of our Solar System
    • Planetquest Flash
  • Beyond Our Solar System by NASA's Solar System Exploration
  • German Center for Exo-Planet Research Jena/Tautenburg
  • Astrophysical Institute & University Observatory Jena (AIU)
  • The Extrasolar Planets Encyclopaedia
  • exosolar.net 3D Flash StarMap (2000 Stars and all known Exoplanets)
  • Table of known planetary systems
  • Extrasolar Planet XML Database
  • Andrew Collier Cameron, Extrasolar planets, Physics World (January 2001). (See the online version.)
  • searchable dynamic database of extrasolar planets and their parent stars
  • List of important exoplanets
  • Extrasolar Planets - D. Montes, UCM
  • Extrasolar Visions
  • Exoplanets at Paris Observatory
  • Exoplanet Habitable Zone Candidates
  • Exoplanet Habitable Zone Residents
News
  • Exoplanets Exhibit at the American Museum of Natural History in New York City
  • First direct image of an exoplanet from universetoday.com
  • 6–8 Earth-Mass Planet Discovered orbiting Gliese 876
  • Newfound World Shatters Distance Record from space.com
  • Oldest Known World from space.com
  • Earth Sized Planets Confirmed from space.com
  • Sunshade to Look for Distant Life from news.bbc.co.uk


  Results from FactBites:
 
Extrasolar Planet Detection with the AFOE (800 words)
Extrasolar planet detection is the search for planets around other stars than our Sun.
The advanced fiber-optic echelle (AFOE) and extrasolar planet searches, where we discuss the status of the instrument, as well as an upgrade to the instrument, a Fabry-Perot reference, which may prove important both for the AFOE and for all Precision Radial Velocity (PRV) facilities.
"51 Pegasi and Tau Boötis: Planets or Pulsations", where we discuss the suggestion (Gray 1997) that the radial velocity variations observed in the spectra of 51 Pegasi are the result of stellar pulsations as opposed to the reflex motion due to an orbital companion.
Extrasolar planet (1133 words)
Extrasolar planets were discovered during the 1990s as a result of improved telescope technology, such as CCD and computer-based image processing along with the Hubble Space Telescope.
One possible answer to these unexpected planetary orbits is that since astrometrics detects the extrasolar planets due to their gravitational influences and partially-ecliptic interference, perhaps current technology only permits the detection of systems where a large planet is close to the orbited star, rather than such systems being the norm.
The frequency of extrasolar planets is one of the parameters in the Drake equation, which attempts to estimate the probability of communications with extraterrestrial intelligence.
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