Proxima Centauri

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Proxima Centauri
Position from Proxima Centauri.png
Observational Data
Designation Proxima Centauri
Right ascension 14h 29m 42.9487s[1]
Declination −62° 40′ 46.141″[1]
Constellation Centaurus
Type of object Red dwarf
Magnitude Apparent: +11.05[2]
Absolute: +15.49[3]
Astrometry
Distance from Earth 4.243 ly[4]
Radial velocity −22.4±0.5 km/s[5]
Proper motion RA: −3775.75 mas/yr[1]
Dec.: 769.33 mas/yr[1]
Parallax 769.8±6.1 mas[1]

Proxima Centauri is a spectral class M5.5Ve red dwarf star in the constellation of Centaurus.[4] At just over 4.243 Light years away, Proxima Centauri is the nearest star to the Solar System. It was first discovered in 1915 by the astronomer Robert Innes and is not visible by the naked eye. It is often considered the third star in the Alpha Centauri system due to having the same proper motion as Alpha Centauri A & B. Due to the star's great distance of around 15,000 AUs (roughly one-fifth of a light year) from Alpha Centauri A & B, astronomers debate if Proxima Centauri is gravitationally bound to the other two stars.

Due to the close proximity of the star, its angular diameter can be measured directly, revealing a diameter 14.5% the size of our Sun. Proxima Centauri appears to have only 10.7% of the sun's mass, and a visual luminosity so low, it would be 19,000 times less luminous then our Sun is if it were at the same distance.[6]

Proxima Centauri, like many M class red dwarfs, is a flare star that may brighten suddenly to many times its normal luminosity. Visual evidence of such flare activity occurred from May to August 1995 when several fares were recorded.[7][8]

At present, Proxima Centauri is moving towards us at a rate of 22.4 km/s.[5] The star will reach its closest approach to our Solar System in some 26,700 years and will be only 3.11 light years away at this point, afterwards the star will slowly move way.[9]

Thus far, the search for substellar companions orbiting Proxima Centauri have yielded no results, more precise instruments would be required to find an Earth sized world. Due to the star's extremely small habitable zone and the sudden increase in electromagnetic radiation from occasional flares, scientists debate if a life-bearing planet could exist there at all.[10]

References

  1. 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (2007). Validation of the new Hipparcos reduction. Astronomy & Astrophysics, 474(2), pp.653-664. arXiv:0708.1752
  2. Proxima centauri from the SIMBAD Astronomical Database
  3. From definition of absolute magnitude, using apparent magnitude (+11.05) and distance (4.243 ly) given here.
  4. 4.0 4.1 Proxima Centauri from constellation-guide.com
  5. 5.0 5.1 Torres, C., Quast, G., da Silva, L., de la Reza, R., Melo, C. and Sterzik, M. (2006). Search for associations containing young stars (SACY): I. Sample & Searching Method. Astronomy & Astrophysics, 460(3), pp.695-708. arXiv:astro-ph/0609258
  6. Alpha Centauri-3 from solstation.com
  7. Davenport, J., Kipping, D., Sasselov, D., Matthews, J. and Cameron, C. (2016). Most Observations of Our Nearest Neighbor: Flares on Proxima Centauri. The Astrophysical Journal, 829(2), p.L31. arXiv:1608.06672 [astro-ph.SR]
  8. Solar-Like M-Class X-ray Flares on Proxima Centauri Observed by the ASCA Satellite from sciencemag.org
  9. García-Sánchez, J., Weissman, P., Preston, R., Jones, D., Lestrade, J., Latham, D., Stefanik, R. and Paredes, J. (2001). Stellar encounters with the solar system. Astronomy & Astrophysics, 379(2), pp.634-659. Online
  10. Tarter, J. C. et al. (2007). A Re-appraisal of the Habitability of Planets Around M Dwarf Stars. Astrobiology, 7(1), pp.30-65. arXiv:astro-ph/0609799