Proxima Centauri

Proxima Centauri

False color Hubble Space Telescope WFPC2 image taken in 2013. The bright lines are diffraction spikes.
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Centaurus
Pronunciation /ˌprɒksəmə sɛnˈtɔːri/ or
/ˈprɒksɪmə sɛnˈtɔːraɪ/[1]
Right ascension 14h 29m 42.946s[2]
Declination −62° 40′ 46.16″[2]
Apparent magnitude (V) 10.43 – 11.11[3]
Characteristics
Evolutionary stage Main sequence
Spectral type M5.5Ve[4]
Variable type UV Cet + BY Dra[3]
Astrometry
Radial velocity (Rv)−22.204±0.032[5] km/s
Proper motion (μ) RA: −3781.741 mas/yr[2]
Dec.: 769.465 mas/yr[2]
Parallax (π)768.0665±0.0499 mas[2]
Distance4.2465 ± 0.0003 ly
(1.30197 ± 0 pc)
Absolute magnitude (MV)15.60[6]
Orbit[5]
PrimaryAlpha Centauri AB
CompanionProxima Centauri
Period (P)547,000+6,600
−4,000 yr
Semi-major axis (a)8,700+700
−400 AU
Eccentricity (e)0.50+0.08
−0.09
Inclination (i)107.6+1.8
−2.0°
Longitude of the node (Ω)126±5°
Periastron epoch (T)+283+59
−41
Argument of periastron (ω)
(secondary)		72.3+8.7
−6.6°
Details
Mass0.1221±0.0022[5] M☉
Radius0.1542±0.0045[5] R☉
Luminosity (bolometric)0.001567±0.000020[7] L☉
Luminosity (visual, LV)0.00005[nb 1] L☉
Habitable zone inner limit0.03731±0.0075 au[8]
Habitable zone outer limit0.088±0.017 au[8]
Surface gravity (log g)5.20±0.23[9] cgs
Temperature2,992+49
−47[7] K
Metallicity [Fe/H]0.21[10][nb 2] dex
Rotation83.2±1.6[8] days
Rotational velocity (v sin i)< 0.1[13] km/s
Age4.85[14] Gyr
Other designations
Alf Cen C, Alpha Centauri C, V645 Centauri, GJ 551, HIP 70890, CCDM J14396-6050C, LFT 1110, LHS 49, LPM 526, LTT 5721, NLTT 37460[15]
Database references
SIMBADdata
Exoplanet Archivedata
ARICNSdata

Proxima Centauri is the nearest star to Earth after the Sun, located 4.25 light-years away in the southern constellation of Centaurus. Discovered in 1915 by Robert Innes, it is a small, low-mass star, too faint to be seen with the naked eye, with an apparent magnitude of 11.13. Proxima Centauri is a member of the Alpha Centauri star system, being identified as component Alpha Centauri C, and is 2.18° to the southwest of the Alpha Centauri AB pair. It is currently 12,950 AU (0.2 ly) from AB, which it orbits with a period of about 550,000 years. Its Latin name means the 'nearest star of Centaurus'.

Proxima Centauri is a red dwarf star with a mass about 12.5% of the Sun's mass (M☉), and average density about 33 times that of the Sun. Because of Proxima Centauri's proximity to Earth, its angular diameter can be measured directly. Its actual diameter is about one-seventh (14%) the diameter of the Sun. Although it has a very low average luminosity, Proxima Centauri is a flare star that randomly undergoes dramatic increases in brightness because of magnetic activity. The star's magnetic field is created by convection throughout the stellar body, and the resulting flare activity generates a total X-ray emission similar to that produced by the Sun. The internal mixing of its fuel by convection through its core and Proxima's relatively low energy-production rate, mean that it will be a main-sequence star for another four trillion years.

Proxima Centauri has two known exoplanets and one candidate exoplanet: Proxima Centauri b, Proxima Centauri d and the disputed Proxima Centauri c.[nb 3] Proxima Centauri b orbits the star at a distance of roughly 0.05 AU (7.5 million km) with an orbital period of approximately 11.2 Earth days. Its estimated mass is at least 1.06 times that of Earth.[8] Proxima b orbits within Proxima Centauri's habitable zone—the range where temperatures are right for liquid water to exist on its surface—but, because Proxima Centauri is a red dwarf and a flare star, the planet's habitability is highly uncertain. A sub-Earth, Proxima Centauri d, roughly 0.028 AU (4.2 million km) away, orbits it every 5.1 days.[8] A candidate sub-Neptune, Proxima Centauri c, roughly 1.5 AU (220 million km) away from Proxima Centauri, orbits it every 1,900 d (5.2 yr).[16][17]

  1. ^ "Collins English Dictionary". HarperCollins Publishers. Retrieved 30 September 2020.
  2. ^ a b c d Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  3. ^ a b Samus', N. N; Kazarovets, E. V; Durlevich, O. V; Kireeva, N. N; Pastukhova, E. N (2017). "General catalogue of variable stars". Astronomy Reports. GCVS 5.1. 61 (1): 80. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
  4. ^ Bessell, M. S. (1991). "The late-M dwarfs". The Astronomical Journal. 101: 662. Bibcode:1991AJ....101..662B. doi:10.1086/115714.
  5. ^ a b c d Kervella, P.; Thévenin, F.; Lovis, C. (2017). "Proxima's orbit around α Centauri". Astronomy & Astrophysics. 598: L7. arXiv:1611.03495. Bibcode:2017A&A...598L...7K. doi:10.1051/0004-6361/201629930. ISSN 0004-6361. S2CID 50867264. Separation: 3.1, left column of page 3; Orbital period and epoch of periastron: Table 3, right column of page 3.
  6. ^ Cite error: The named reference apj118 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Pineda2021 was invoked but never defined (see the help page).
  8. ^ a b c d e Cite error: The named reference SuárezMascareño2025 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference aaa397 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference aaa519_A105 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference PasseggerWende-von Berg2016 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference FengJones2018 was invoked but never defined (see the help page).
  13. ^ Collins, John M.; Jones, Hugh R. A.; Barnes, John R. (June 2017). "Calculations of periodicity from Hα profiles of Proxima Centauri". Astronomy & Astrophysics. 602. A48. arXiv:1608.07834. Bibcode:2017A&A...602A..48C. doi:10.1051/0004-6361/201628827. S2CID 18949162. See section 4: "the vsini is probably less than 0.1 km/s for Proxima Centauri".
  14. ^ Cite error: The named reference ESO2003 was invoked but never defined (see the help page).
  15. ^ "Proxima centauri". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 28 April 2022.—some of the data is located under "Measurements".
  16. ^ Cite error: The named reference Damasso2020 was invoked but never defined (see the help page).
  17. ^ Cite error: The named reference BenedictMcArthur2020 was invoked but never defined (see the help page).


Cite error: There are <ref group=nb> tags on this page, but the references will not show without a {{reflist|group=nb}} template (see the help page).

This article is issued from Wikipedia. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.