Omicron1 Centauri (ο1 Cen, ο1 Centauri) is a star in the constellation Centaurus. It is approximately 10,000 light years from Earth.

ο1 Centauri
Location of ο1 Cen (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Centaurus
Right ascension 11h 31m 46.07s[1]
Declination −59° 26′ 31.4″[1]
Apparent magnitude (V) +5.13[2]
Characteristics
Spectral type G3 0-Ia[3][4]
B−V color index +1.08[2]
Variable type SRd[5]
Astrometry
Radial velocity (Rv)−20.00[6] km/s
Proper motion (μ) RA: −4.491[1] mas/yr
Dec.: +1.604[1] mas/yr
Parallax (π)0.3254 ± 0.0734 mas[1]
Distanceapprox. 10,000 ly
(approx. 3,100 pc)
Absolute magnitude (MV)−9.0[4]
Details
Mass17[7] M
Radius270[7] R
Luminosity68,000[7] L
Surface gravity (log g)0.19[8] cgs
Temperature4,873[9] K
Age10–12[7] Myr
Other designations
HR 4441, HD 100261, CD−58°4100, HIP 56243, SAO 239145, GC 15818, CCDM J11318-5927, AAVSO 1127-58
Database references
SIMBADdata
A light curve for Omicron1 Centauri, adapted from O'Connell (1961)[10]

ο1 Centauri is a yellow G-type supergiant or hypergiant with a mean apparent magnitude of +5.13. It is classified as a semiregular variable star and its brightness varies from magnitude +5.8 to +6.6 with a period of 200 days.[5] Other studies have reported only small brightness variations.[11][12] It is the MK spectral standard for class G3 O-Ia,[13] indicating a highly luminous mass-losing hypergiant star. It has also be classified as F8 Ia0[14] and F7 Ia/ab.[15] The size, luminosity, and distance are equally uncertain.

ο1 Cen forms a very close naked eye double star with ο2 Centauri, a hotter supergiant that may be physically associated. ο1 Cen also has an 11th magnitude companion only 13.5" distant,[16] Although it appears to be a foreground star unrelated to the other two.[17]

References edit

  1. ^ a b c d e 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.
  2. ^ a b Malyuto, V.; Schmidt-Kaler, T. (1997). "Quantitative spectral classification based on photoelectric spectrum scanner measurements of F-K stars". Astronomy and Astrophysics. 325: 693. Bibcode:1997A&A...325..693M.
  3. ^ Keenan, P. C.; Pitts, R. E. (1980). "Revised MK spectral types for G, K, and M stars". Astrophysical Journal Supplement Series. 42: 541. Bibcode:1980ApJS...42..541K. doi:10.1086/190662.
  4. ^ a b Arellano Ferro, A.; Giridhar, Sunetra; Goswami, Aruna (1991). "A new discussion on the M(v) - W(O I 7774 A) relationship for F-G stars in the light of high-resolution data". Monthly Notices of the Royal Astronomical Society. 250: 1. Bibcode:1991MNRAS.250....1A. doi:10.1093/mnras/250.1.1.
  5. ^ a b Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
  6. ^ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
  7. ^ a b c d Kaler, James B., "Omicron 1,2 Centauri", Stars, University of Illinois, retrieved 2017-12-05
  8. ^ Mallik, Sushma V. (1998). "The central depth of the Ca II triplet lines as a discriminant of chromospheric activity in late type stars". Bulletin of the Astronomical Society of India. 26: 479. Bibcode:1998BASI...26..479M.
  9. ^ McDonald, I.; Zijlstra, A. A.; Boyer, M. L. (2012). "Fundamental parameters and infrared excesses of Hipparcos stars". Monthly Notices of the Royal Astronomical Society. 427 (1): 343–357. arXiv:1208.2037. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x. S2CID 118665352.
  10. ^ O'Connell, D. J. K. (1961). "The semi-regular variable o1 Centauri". Ricerche Astronomiche. 6 (13): 353–359. Bibcode:1961RA......6..353O.
  11. ^ Friedrich, D.; Schoffel, E. (1971). "New Bright Southern Variable Stars". Information Bulletin on Variable Stars. 558: 1. Bibcode:1971IBVS..558....1F.
  12. ^ Sterken, C.; Manfroid, J.; Anton, K.; Barzewski, A.; Bibo, E.; Bruch, A.; Burger, M.; Duerbeck, H. W.; Duemmler, R.; Heck, A.; Hensberge, H.; Hiesgen, M.; Inklaar, F.; Jorissen, A.; Juettner, A.; Kinkel, U.; Liu, Zongli; Mekkaden, M. V.; Ng, Y. K.; Niarchos, P.; Puttmann, M.; Szeifert, T.; Spiller, F.; Van Dijk, R.; Vogt, N.; Wanders, I. (1993). "Longterm Photometry of Variables at ESO - Part Two - the Second Data Catalogue 1986-1990". Astronomy and Astrophysics Supplement. 102: 79. Bibcode:1993A&AS..102...79S.
  13. ^ Garcia, B. (1989). "A list of MK standard stars". Bulletin d'Information du Centre de Données Stellaires. 36: 27. Bibcode:1989BICDS..36...27G.
  14. ^ Mantegazza, L. (1992). "Luminosities of yellow supergiants from near-infrared spectra - Calibration through Magellanic Cloud stars". Astronomy and Astrophysics. 265: 527. Bibcode:1992A&A...265..527M.
  15. ^ Sowell, James R. (1990). "A survey of Balmer-line profiles and IRAS fluxes in forty yellow supergiants". Astronomical Journal. 100: 834. Bibcode:1990AJ....100..834S. doi:10.1086/115567.
  16. ^ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
  17. ^ 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.