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Proxima Centauri (star)

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Proxima Centauri, discovered in 1915[1] is an M class dwarf star (also known as a red dwarf and classed as M5.5) in the constellation Centaurus, one of a group of three which includes, Alpha Centauri A and Alpha Centauri B.[2]

Alternate names and catalogue numbers

  • Alpha Centauri C (Bayer designation)
  • V645 Cen
  • Gl551
  • GJ551
  • 70890 (HIP)
  • LHS 49

[3][4][5][6]

Proximity and properties

Proxima Centauri is the closest star to earth, located about 4.2 light years from earth. [2][5]

Proxima Centauri is much smaller than earth’s star, Sol, at about 11% of Sol’s mass and is visible only through a telescope. Proxima Centauri has a surface temperature of about 3,100 C and is far less bright than Sol with an absolute magnitude of 15.53 Mv,[7][6] making our sun about 18,716 times brighter[8][9]

Proxima Centauri is a very active variable star. As a star of low mass it converts hydrogen to helium very slowly compared to our own star. Sol. This slow conversion creates a turbulent convection motion within the star, storing up magnetic energy, which is released suddenly in the star’s upper atmosphere, producing flares of X-ray and other light forms. The same process produces X-rays in Sol but greater mass of Sol confines the convection currents to its surface. For this reason, the energy is not released as explosively, creating loops of gas and occasional flares.

Since Proxima Centauri is much smaller and dimmer it will shine much longer than Sol, over a period of trillions of years compared to our sun which has an estimated lifetime of about 10 billion years.[10][9]

Location

Proxima Centauri is located on the celestial sphere coordinates[11] at right ascension 14 hours 29 minutes 43seconds (14h 29m 43s) and declination -62 degrees 40 arcminutes 46 arcseconds (-62°40’46”).[10][12] [13] [14][15][16]

References

  1. Proxima Centauri: The Closest Star NASA
  2. 2.0 2.1 Star NASA
  3. The Closest star to the Earth
  4. Proxima Centauri
  5. 5.0 5.1 A list of the nearest stars
  6. 6.0 6.1 The 100 nearest star systems
  7. Proxima Centauri, the nearest star Anglo-Australian Observatory
  8. Note: Sol has an absolute magnitude of 4.85 Mv. Higher numbers indicate less brightness and the brightest stars have values in the negative numbers. Absolute magnitude is the brightness of a star at 10 parsecs, about 33 light years away. A star that is one absolute magnitude brighter than another (e.g., +1 versus +2) is 2.512 times brighter; a star that is 5 absolute magnitudes brighter is 100 times intrinsically brighter; and a star that is 10 absolute magnitudes brighter is 10000 times brighter. There are 10.68 degrees of magnitude difference between Sol and Proxima Centauri. 2.512 E10.68 = 18,715.85632. See Astronomy knowledge base and Magnitude System Nick Strobel, Physical Science Dept., Bakersfield College, Bakersfield CA
  9. 9.0 9.1 Rigil Kentaurus Jim Kaler, Dept of Astronomy, University of Illinois, Urbana-Champaign
  10. 10.0 10.1 Proxima Centauri: The nearest star to the sun Chandra X-ray Observatory
  11. Note: The celestial sphere has an earth correlated equator which is a projection of the same coordinates of earth. The correlating prime meridian runs through the vernal equinox (i.e. 0 hours 0 minutes & 0 seconds) marking the time from the vernal equinox in a 24-hour circle. So declination (latitude) for stars will directly correlate with that of earth and right ascension (longitude) correlates to a sphere that circumscribes earth’s orbital path around Sol. See Celestial Coordinate System University of Tennessee; and Celestial Coordinates James Schombert, Dept. of Physics, Univ. of Oregon
  12. See illustration at The universe within 12.5 light years Richard Powell
  13. Research Consortium on Nearby Stars (RECONS)
  14. Recon census of objects nearer than 10 parsecs
  15. The 100 nearest star systems
  16. Nearby stars database Northern Arizona University

Internal Links

Wolf 359 (star)

Stellar classification (astrophysics)

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