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Encyclopedia > Proxima Centauri
Proxima Centauri

Proxima Centauri (not shown) is near Toliman (α Centauri) in lower portion of this diagram.
Observation data
Epoch J2000
Constellation Centaurus
Right ascension 14h 29m 42.9487s[1]
Declination −62° 40′ 46.141″[1]
Apparent magnitude (V) 11.05[1]
Characteristics
Spectral type M5.5 Ve[1]
U-B color index 1.49
B-V color index 1.90
Variable type Flare star
Astrometry
Radial velocity (Rv) -20.3 km/s
Proper motion (μ) RA: -3775.64[1] mas/yr
Dec.: 768.16[1] mas/yr
Parallax (π) 771.99 ± 2.25 mas
Distance 4.22 ± 0.01 ly
(1.295 ± 0.004 pc)
Absolute magnitude (MV) 15.49
Details
Mass 0.123[2] M
Radius 0.145[2] R
Luminosity 1.38 × 10-4[2] L
Temperature 3,040[2] K
Metallicity 10%
Rotation 83.5 days[3]
Age 4.85 × 109[2] years
Other designations
α Centauri C, V645 Centauri, GCTP 3278.00, GJ 551, LHS 49, LFT 1110, LTT 5721, HIP 70890.[1]

Proxima Centauri (Latin proximus, -a, -um: meaning 'next to' or 'nearest to')[4] is a red dwarf star that is likely a part of the Alpha Centauri star system and is the nearest star to the Sun at a distance of 4.22 light years. As the name suggests, it is located in the constellation of Centaurus. This file has been listed on Wikipedia:Images and media for deletion. ... In astronomy, an epoch is a moment in time for which celestial coordinates or orbital elements are specified. ... This article does not cite any references or sources. ... Centaurus (Latin for centaur) was one of the 48 constellations listed by Ptolemy, and counts also among the 88 modern constellations. ... Equatorial Coordinates Right ascension (abbrev. ... In astronomy, declination (abbrev. ... The apparent magnitude (m) of a star, planet or other celestial body is a measure of its apparent brightness as seen by an observer on Earth. ... 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. ... In astronomy, the color index is a simple numerical expression that determines the color of an object, which in the case of a star gives its temperature. ... In astronomy, the color index is a simple numerical expression that determines the color of an object, which in the case of a star gives its temperature. ... This article or section contains a plot summary that is overly long or excessively detailed. ... A flare star is a variable star which can undergo unpredictable dramatic increases in brightness for a few minutes or a few hours. ... Illustration of the use of optical wavelength interferometry to determine precise positions of stars. ... Radial velocity is the velocity of an object in the direction of the line of sight. ... kilometre per second is an SI derived unit of both speed (scalar) and velocity (vector), signified by the symbol km/s or km s-1. ... The proper motion of a star is the motion of the position of the star in the sky (the change in direction in which we see it, as opposed to the radial velocity) after eliminating the improper motions of the stars, which affect their measured coordinates but are not real... A milliarcsecond (m, mas) , or a thoundsanth of an arcsecond. ... A year (from Old English gÄ“r) is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... A milliarcsecond (m, mas) , or a thoundsanth of an arcsecond. ... A year (from Old English gÄ“r) is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... This does not adequately cite its references or sources. ... A milliarcsecond (m, mas) , or a thoundsanth of an arcsecond. ... Distance is a numerical description of how far apart objects are at any given moment in time. ... A light-year or lightyear (symbol: ly) is a unit of measurement of length, specifically the distance light travels in vacuum in one year. ... A parsec is the distance from the Earth to an astronomical object which has a parallax angle of one arcsecond. ... In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standard luminosity distance away from us, in the absence of interstellar extinction. ... This article or section is in need of attention from an expert on the subject. ... In astronomy, the solar mass is a unit of mass used to express the mass of stars and larger objects such as galaxies. ... Remote Authentication Dial In User Service (RADIUS) is an AAA (authentication, authorization and accounting) protocol for applications such as network access or IP mobility. ... In astronomy, the solar radius is a unit of length used to express the size of stars and larger objects such as galaxies. ... Luminosity has different meanings in several different fields of science. ... The solar luminosity, , is a unit of luminosity (power emitted in the form of photons) conventionally used by astronomers to give the luminosities of stars. ... This article includes a list of works cited or a list of external links, but its sources remain unclear because it lacks in-text citations. ... The kelvin (symbol: K) is a unit increment of temperature and is one of the seven SI base units. ... The globular cluster M80. ... This illustration shows the oblate appearance of the star Achernar caused by rapid rotation. ... STAR is an acronym for: Organizations Society of Ticket Agents and Retailers], the self-regulatory body for the entertainment ticket industry in the UK. Society for Telescopy, Astronomy, and Radio, a non-profit New Jersey astronomy club. ... A year (from Old English gÄ“r) is the time between two recurrences of an event related to the orbit of the Earth around the Sun. ... A star catalogue, or star catalog, is an astronomical catalog that lists stars. ... This article or section contains a plot summary that is overly long or excessively detailed. ... In astronomy, many stars are referred to simply by catalogue numbers. ... Wilhelm Gliese (June 21, 1915 – June 12, 1993) was a German astronomer. ... In astronomy, many stars are referred to simply by catalogue numbers. ... In astronomy, many stars are referred to simply by catalogue numbers. ... In astronomy, many stars are referred to simply by catalogue numbers. ... The Hipparcos and Tycho Catalogues (Tycho-1) are the primary products of the European Space Agencys astrometric mission, Hipparcos. ... Latin was the language originally spoken in the region around Rome called Latium. ... Red Dwarf is a British science fiction comedy franchise, the primary form of which comprises eight series of a post-watershed television sitcom that ran on BBC2 between 1988 and 1999, and which has achieved a global cult following. ... STAR is an acronym for: Organizations Society of Ticket Agents and Retailers], the self-regulatory body for the entertainment ticket industry in the UK. Society for Telescopy, Astronomy, and Radio, a non-profit New Jersey astronomy club. ... Alpha Centauri (α Cen / α Centauri, also known as Rigil Kentaurus), is the brightest star system in the southern constellation of Centaurus. ... This list of the nearest stars to Earth is ordered by increasing distance out to a maximum of 5 parsecs (16. ... The Sun (Latin: Sol) is the star at the center of the Solar System. ... Centaurus (Latin for centaur) was one of the 48 constellations listed by Ptolemy, and counts also among the 88 modern constellations. ...


Proxima Centauri is categorized as a flare star, as it undergoes random increases in luminosity because of magnetic activity. It only has about an eighth of the Sun's mass, and consequently it has a very low luminosity. Because of its proximity, the size of this star can be measured directly, giving a diameter only one-seventh the size of the Sun. A flare star is a variable star which can undergo unpredictable dramatic increases in brightness for a few minutes or a few hours. ...

Contents

Observation history

Proxima Centauri was discovered to share the same proper motion as Alpha Centauri in 1915 by Robert Innes while he was Director of the Union Observatory in Johannesburg, South Africa.[5] Innes also suggested the name Proxima Centauri for the star. In 1917 at the Royal Observatory at the Cape of Good Hope, the Dutch astronomer J. Voûte measured the trigonometric parallax and determined that Proxima Centauri was indeed the same distance from the Sun as Alpha Centauri and hence was also the lowest luminosity star known at the time.[6] The proper motion of a star is the motion of the position of the star in the sky (the change in direction in which we see it, as opposed to the radial velocity) after eliminating the improper motions of the stars, which affect their measured coordinates but are not real... Year 1915 (MCMXV) was a common year starting on Friday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Thursday[1] of the 13-day-slower Julian calendar). ... Robert Thorburn Ayton Innes (November 10, 1861 – March 13, 1933) was a Scottish-South African astronomer best known for discovering Proxima Centauri in 1915, and numerous binary stars. ... Union Observatory was an astronomical observatory located in Johannesburg, South Africa. ... This article does not cite any references or sources. ... STAR is an acronym for: Organizations Society of Ticket Agents and Retailers], the self-regulatory body for the entertainment ticket industry in the UK. Society for Telescopy, Astronomy, and Radio, a non-profit New Jersey astronomy club. ... 1917 (MCMXVII) was a common year starting on Monday of the Gregorian calendar (see link for calendar) or a common year starting on Tuesday of the 13-day slower Julian calendar (see: 1917 Julian calendar). ... Royal Observatory can refer to: Royal Greenwich Observatory, London Royal Observatory, Edinburgh This is a disambiguation page, a list of pages that otherwise might share the same title. ... The Cape of Good Hope; looking towards the west, from the coastal cliffs above Cape Point. ... This does not adequately cite its references or sources. ... STAR is an acronym for: Organizations Society of Ticket Agents and Retailers], the self-regulatory body for the entertainment ticket industry in the UK. Society for Telescopy, Astronomy, and Radio, a non-profit New Jersey astronomy club. ...


In 1951, Harlow Shapley announced that Proxima Centauri was a flare star. Examination of past photographic records showed that the star displayed a measureable increase in magnitude about 8% of the time, making it the most active flare star then discovered.[7] Harlow Shapley in his earlier years. ...


Characteristics

Red dwarfs in general are far too faint to be observable with the naked eye, and Proxima Centauri is no exception. It has an apparent magnitude of 11 while its absolute magnitude is a very dim 15.5. Even from Alpha Centauri A or B, Proxima would only be seen as a 5th magnitude star.[8] The apparent magnitude (m) of a star, planet or other celestial body is a measure of its apparent brightness as seen by an observer on Earth. ... In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standard luminosity distance away from us, in the absence of interstellar extinction. ... Alpha Centauri (α Cen / α Centauri, also known as Rigil Kentaurus), is the brightest star system in the southern constellation of Centaurus. ...


Based on the parallax of 772.3 ± 2.4 milliarcseconds measured by Hipparcos (and the more precise parallax determined using the Fine Guidance Sensors on the Hubble Space Telescope of 768.7 ± 0.3[9] milliarcseconds), Proxima Centauri is roughly 4.2 light years from Earth, or 270,000 times more distant than the Sun. Its closest neighbors are Alpha Centauri A and B (at 0.21 light years), the Sun, and Barnard's Star (at 6.6 light years).[10][11] From Earth's vantage point, Proxima is separated by 2.2°[12] from Alpha Centauri, or 4 times the angular diameter of the full Moon. This does not adequately cite its references or sources. ... Hipparcos (for High Precision Parallax Collecting Satellite) was an astrometry mission of the European Space Agency (ESA) dedicated to the measurement of stellar parallax and the proper motions of stars. ... The Hubble Space Telescope (HST) is a telescope in orbit around the Earth, named after astronomer Edwin Hubble. ... Alpha Centauri (α Cen / α Centauri, also known as Rigil Kentaurus), is the brightest star system in the southern constellation of Centaurus. ... Barnards Star is a very low-mass star in the constellation Ophiuchus which was discovered by the astronomer E. E. Barnard in 1916. ... Alpha Centauri (α Cen / α Centauri, also known as Rigil Kentaurus), is the brightest star system in the southern constellation of Centaurus. ... The angular diameter of an object as seen from a given position is the diameter measured as an angle. ... Apparent magnitude: up to -12. ...


At least among the known stars, Proxima Centauri has been the closest star to the Sun for about the last 32,000 years and will be so for about another 9,000 years, when it will be replaced by Barnard's Star.[13] Proxima Centauri has a relatively large proper motion—moving 3.85 arcseconds per year across the sky.[14] Barnards Star is a very low-mass star in the constellation Ophiuchus which was discovered by the astronomer E. E. Barnard in 1916. ... The proper motion of a star is the motion of the position of the star in the sky (the change in direction in which we see it, as opposed to the radial velocity) after eliminating the improper motions of the stars, which affect their measured coordinates but are not real... 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 relative size of Proxima Centauri (right) compared to its nearest neighbors.

In 2002, VLTI used optical interferometry to measure an angular diameter of 1.02 ± 0.08 milliarcsec for Proxima Centauri. Because its distance is known, the actual diameter of Proxima Centauri can be calculated to be about 1/7 that of the Sun, or 1.5 times that of Jupiter.[5] Download high resolution version (3770x1368, 56 KB) File links The following pages link to this file: Alpha Centauri User:Dbenbenn/gallery ... Download high resolution version (3770x1368, 56 KB) File links The following pages link to this file: Alpha Centauri User:Dbenbenn/gallery ... The four telescopes of the European Southern Observatory Paranal site. ... This article is in need of attention. ... The angular diameter of an object as seen from a given position is the diameter measured as an angle. ... Atmospheric characteristics Atmospheric pressure 70 kPa Hydrogen ~86% Helium ~14% Methane 0. ...


Because of its low mass, the interior of the star is completely convective, which means that energy is transferred to the exterior by the physical movement of plasma (rather than through radiative processes). Convection is associated with the generation and storage of a magnetic field. The magnetic energy from this field is released at the surface through stellar flares that briefly increase the overall luminosity of the star. These flares are hot enough to radiate X-rays,[15] and indeed the quiescent X-ray luminosity of this star is roughly equal to that of the much larger Sun. However, the overall activity level of this star is considered relatively low compared to other M-class dwarfs.[16] This activity appears to vary with a period of roughly 442 days.[17] The convection zone is the outermost layer of the suns interior. ... The radiation zone is the middle zone in the suns interior. ... The magnetic field of the Sun is driving this massive ejection of plasma. ... A solar flare observed by Hinode in the G-band. ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz...

RV-derived Upper Mass
Limits of Companion[18]
Orbital
period

(days)
Separation
(A.U.)
Maximum
Mass
Jupiter)
50 0.13 3.7
600 0.69 8.3
3000 1.00 22

Proxima Centauri, along with Alpha Centauri A and B, are among the "Tier 1" target stars for NASA's proposed Space Interferometry Mission (SIM). Theoretically, SIM will be able to detect planets as small as three Earth-masses within two Astronomical Units of a "Tier 1" target.[19] Should a massive planet orbit Proxima Centauri, some displacement of the star would be expected to occur over the course of each orbit. If this orbital plane is inclined toward the line of sight from the Earth then this displacement would cause changes in the radial velocity of Proxima Centauri. However no such shifts have yet been observed despite multiple radial velocity measurements. This puts significant constraints on the maximum mass that such a companion could possess.[18][9] The orbital period is the time it takes a planet (or another object) to make one full orbit. ... The semi-major axis of an ellipse In geometry, the term semi-major axis (also semimajor axis) is used to describe the dimensions of ellipses and hyperbolae. ... Adjectives: Jovian Atmosphere Surface pressure: 20–200 kPa[4] (cloud layer) Composition: ~86% Molecular hydrogen ~13% Helium 0. ... The National Aeronautics and Space Administration (NASA) is an agency of the United States federal government, responsible for the nations public space program. ... 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. ... The astronomical unit (AU or au or a. ... Radial velocity is the velocity of an object in the direction of the line of sight. ...


Proxima Centauri has been suggested as a logical first destination for interstellar travel, although as a flare star it would not be particularly hospitable. However, even at the fastest speed currently attained by a manned vehicle the journey to Proxima Centauri would take ~32,000 years.[20] Artists Impression of the compression of a viewers perspective in front of a ship during interstellar travel Interstellar space travel is unmanned or manned travel between stars, though the term usually denotes the latter. ... A flare star is a variable star which can undergo unpredictable dramatic increases in brightness for a few minutes or a few hours. ... It has been suggested that Space firsts be merged into this article or section. ...


The Alpha Centauri system

From the time of the discovery of Proxima, it was suggested that it was likely to be a true companion of the Alpha Centauri double star system. At a distance to Alpha Centauri of just 0.21ly (15,000 ± 700 AU),[21] Proxima Centauri may be in orbit about Alpha, with an orbital period on the order of 500,000 years or more. For this reason, Proxima is sometimes referred to as Alpha Centauri C. Modern estimates, taking into account the small separation between and relative velocity of the stars, suggest that the chance of the observed alignment being a coincidence is roughly one in 106.[22] Alpha Centauri (α Cen / α Centauri, also known as Rigil Kentaurus), is the brightest star system in the southern constellation of Centaurus. ... A light-year or lightyear (symbol: ly) is a unit of measurement of length, specifically the distance light travels in vacuum in one year. ... The astronomical unit (AU or au or a. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... Alpha Centauri (α Cen / α Centauri, also known as Rigil Kentaurus), is the brightest star system in the southern constellation of Centaurus. ...


The most recent observational work combined data from the Hipparcos satellite with ground-based observations and concluded that the data was consistent with the hypothesis that the three stars are truly a bound system. If so, Proxima would currently be near apastron (the furthest point in its orbit from the Alpha Cen. system). More accurate measurement of the radial velocity would be needed to confirm this conclusion.[21] Hipparcos (for High Precision Parallax Collecting Satellite) was an astrometry mission of the European Space Agency (ESA) dedicated to the measurement of stellar parallax and the proper motions of stars. ... Radial velocity is the velocity of an object in the direction of the line of sight. ...


See also

The planetary systems of stars other than the Sun and its Solar System are a staple element in much science fiction. ... Alpha Centauri (α Cen / α Centauri, also known as Rigil Kentaurus), is the brightest star system in the southern constellation of Centaurus. ... This list of the nearest stars to Earth is ordered by increasing distance out to a maximum of 5 parsecs (16. ...

References

  1. ^ a b c d e f g SIMBAD query result: V* V645 Cen -- Flare Star. Centre de Données astronomiques de Strasbourg. Retrieved on 2007-07-09.
  2. ^ a b c d e Kervella, Pierre; Thevenin, Frederic. "A Family Portrait of the Alpha Centauri System: VLT Interferometer Studies the Nearest Stars", ESO, March 15, 2003. Retrieved on 2007-07-09. 
  3. ^ G. Fritz Benedict et al (1998). "Photometry of Proxima Centauri and Barnard's Star Using Hubble Space Telescope Fine Guidance Sensor 3: A Search for Periodic Variations". The Astronomical Journal 116 (1): 429-439. Retrieved on 2007-07-09. 
  4. ^ Latin Resources. Joint Association of Classical Teachers. Retrieved on 2007-07-15.
  5. ^ a b Queloz, Didier (November 29, 2002). How Small are Small Stars Really? VLT Interferometer Measures the Size of Proxima Centauri and Other Nearby Stars. European Southern Observatory. Retrieved on 2007-07-09.
  6. ^ Voûte, J. (1917). "A 13th magnitude star in Centaurus with the same parallax as α Centauri". Monthly Notices of the Royal Astronomical Society 77: 650-651. Retrieved on 2007-07-09. 
  7. ^ Shapley, Harlow (1951). "Proxima Centauri as a Flare Star". Proceedings of the National Academy of Sciences of the United States of America 37 (1): 15-18. Retrieved on 2007-07-11. 
  8. ^ Proxima Centauri UV Flux Distribution. ESA/Laboratory for Space Astrophysics and Theoretical Physics. Retrieved on 2007-07-11.
  9. ^ a b G. Fritz Benedict et al (1999). "Interferometric Astrometry of Proxima Centauri and Barnard's Star Using HUBBLE SPACE TELESCOPE Fine Guidance Sensor 3: Detection Limits for Substellar Companions". The Astronomical Journal 118 (2): 1086-1100. Retrieved on 2007-07-21. 
  10. ^ Barnard's Star. SolStation. Retrieved on 2007-08-06.
  11. ^ Alpha Centauri 3. SolStation. Retrieved on 2007-07-21.
  12. ^ Wargelin, Bradford J.; Drake, Jeremy J. (2002). "Stringent X-Ray Constraints on Mass Loss from Proxima Centauri". The Astrophysical Journal 587: 503-514. Retrieved on 2007-07-09. 
  13. ^ Bell, George H. (2001). The Search for the Extrasolar Planets: A Brief History of the Search, the Findings and the Future Implications, Section 2.. Arizona State University. Retrieved on 2007-07-09. — Full description of the Van de Kamp planet controversy.
  14. ^ Benedict, G. F. et al. "Astrometric Stability and Precision of Fine Guidance Sensor #3: The Parallax and Proper Motion of Proxima Centauri". Procedings of the HST Calibration Workshop: 380-384. Retrieved on 2007-07-11. 
  15. ^ Staff (August 30, 2006). Proxima Centauri: The Nearest Star to the Sun. Harvard-Smithsonian Center for Astrophysics. Retrieved on 2007-07-09.
  16. ^ Wood, B. E.; Linsky, J. L.; Müller, H.-R.; Zank, G. P. (2001). "Observational Estimates for the Mass-Loss Rates of α Centauri and Proxima Centauri Using Hubble Space Telescope Lyα Spectra". The Astrophysical Journal 547 (1): L49-L52. Retrieved on 2007-07-09. 
  17. ^ Cincunegui, C.; Díaz, R. F.; Mauas, P. J. D. (2007). "A possible activity cycle in Proxima Centauri". Astronomy and Astrophysics 461 (3): 1107-1113. Retrieved on 2007-07-11. 
  18. ^ a b Kürster, M. et al (1999). "Precise radial velocities of Proxima Centauri" (PDF). Astronomy & Astrophysics Letters 344: L5-L8. Retrieved on 2007-07-11. 
  19. ^ Watanabe, Susan (October 18, 2006). Planet-Finding by Numbers. NASA JPL. Retrieved on 2007-07-09.
  20. ^ The distance to Proxima Centauri is:
    (4.22 ly) × (9.46 × 1012 km/ly) = 4.0 × 1013 km
    A year is about 32 million seconds, so completing the journey in 32,000 years (or ~1011 seconds) would require a (non-relativistic) velocity of
    (4.0 × 1013 km) / (1.0 × 1012 seconds) = 40 km/s.
    By comparison, the Apollo 10 achieved a record velocity of 11 km/s.
  21. ^ a b Wertheimer, Jeremy G.; Laughlin, Gregory (2006). "Are Proxima and α Centauri Gravitationally Bound?". The Astronomical Journal 132 (5): 1995-1997. Retrieved on 2007-07-09. 
  22. ^ Matthews, Robert; Gilmore, Gerard (1993). "Is Proxima really in orbit about Alpha CEN A/B?". MNRAS 261: L5. 

Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 190th day of the year (191st 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. ... is the 190th day of the year (191st 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. ... is the 190th day of the year (191st 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. ... is the 196th day of the year (197th 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. ... is the 190th day of the year (191st 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. ... is the 190th day of the year (191st 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. ... 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. ... 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. ... is the 202nd day of the year (203rd 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. ... is the 218th day of the year (219th 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. ... is the 202nd day of the year (203rd 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. ... is the 190th day of the year (191st 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. ... is the 190th day of the year (191st 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. ... 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. ... is the 190th day of the year (191st 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. ... is the 190th day of the year (191st 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. ... 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. ... 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. ... is the 190th day of the year (191st in leap years) in the Gregorian calendar. ... Apollo 10 was the fourth manned mission in the Apollo program, and the first (and only manned Saturn V) mission to launch from pad 39B. The mission included the second crew to orbit the Moon, and the test of the lunar module in lunar orbit. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 190th day of the year (191st in leap years) in the Gregorian calendar. ...

External links


  Results from FactBites:
 
Proxima Centauri - Wikipedia, the free encyclopedia (534 words)
Proxima Centauri was discovered in 1915 by Robert Innes while he was Director of the Union Observatory in Johannesburg, South Africa.
For this reason, Proxima is sometimes referred to as Alpha Centauri C. However, it is not clear if it really is in orbit, although the association is unlikely to be entirely accidental as it shares approximately the same motion through space as the larger star system.
Proxima Centauri has been suggested as a logical first destination for interstellar travel, although as a flare star it would not be particularly hospitable.
PROXIMA CENTAURI (247 words)
Proxima Centauri si trova a circa 4,22 anni luce dalla Terra (pari a 40.000 miliardi di chilometri), una distanza 270.000 volte maggiore di quella del Sole.
Proxima Centauri fu scoperta nel 1915 da Robert Innes, mentre era direttore del Republic Observatory a Johannesburg, in Sudafrica.
Proxima Centauri si trova a solo 13.000 unità astronomiche da Alpha Centauri, una distanza piccola su scala stellare, e potrebbe essere in orbita attorno ad essa, con un periodo dell'ordine dei 500.000 anni o superiore.
  More results at FactBites »

 
 

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