j Centauri
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Centaurus
Right ascension 11h 49m 41.05745s[1]
Declination −63° 47′ 18.4299″[1]
Apparent magnitude (V) 4.30[2] (+4.30 - 4.39)[3]
Characteristics
Spectral type B3V[4]
U−B color index −0.59
B−V color index −0.15
Variable type γ Cas[3]
Astrometry
Radial velocity (Rv)+29.0±4.1[2] km/s
Proper motion (μ) RA: -20.76 ± 0.56[5] mas/yr
Dec.: 4.30 ± 0.48[5] mas/yr
Parallax (π)5.4391 ± 0.4369 mas[1]
Distance600 ± 50 ly
(180 ± 10 pc)
Absolute magnitude (MV)−1.98[2]
Details
Mass5.955 M☉[6]
7.2±0.1[7] M☉
Radius5.00±0.10[8] R☉
Luminosity1,342[2] L☉
Surface gravity (log g)3.20±0.03[8] cgs
Temperature20,000±200[8] K
Rotational velocity (v sin i)200±4[8] km/s
Age31.6±0.6[7] Myr
Other designations
j Cen, NSV 5357, CPD−63°1988, FK5 2944, GC 16201, HD 102776, HIP 57669, HR 4537, SAO 251602[9]
Database references
SIMBADdata

HD 102776, also known by its Bayer designation j Centauri, is a suspected astrometric binary[10] star system in the southern constellation of Centaurus. It has a blue-white hue and is faintly visible to the naked eye with a typical apparent visual magnitude of 4.30.[2] The distance to this star is approximately 600 light years based on parallax, and it is drifting further away with a radial velocity of ~29 km/s.[2] It is a member of the Lower Centaurus Crux subgroup of the Sco OB2 association.[11] HD 102776 has a relatively large peculiar velocity of 31.1 km/s and is a candidate runaway star that was ejected from its association, most likely by a supernova explosion.[12]

The stellar classification of the visible component is B3V,[4] matching a B-type main-sequence star. It is around 32[7] million years old and is spinning rapidly with estimates of its projected rotational velocity ranging from 200[8] up to 270 km, giving it an equatorial bulge that is up to 11% larger than the polar radius.[13] This is a Be star showing emission features in its Balmer lines due to a circumstellar disk of decreated gas.[14] It is classified as a suspected Gamma Cassiopeiae type variable star with a visual magnitude varying from +4.30 down to +4.39.[3]

References

  1. ^ a b c Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b c d e f Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
  3. ^ a b c "NSV 5357". Variable Star Index. American Association of Variable Star Observers. Retrieved 2020-02-19.
  4. ^ a b Houk, Nancy (1979). Michigan catalogue of two-dimensional spectral types for the HD stars. Vol. 1. Ann Arbor, Michigan: Department of Astronomy, University of Michigan. Bibcode:1978mcts.book.....H.
  5. ^ a b van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600. Vizier catalog entry
  6. ^ Kervella, Pierre; Arenou, Frédéric; Mignard, François; Thévenin, Frédéric (2019). "Stellar and substellar companions of nearby stars from Gaia DR2. Binarity from proper motion anomaly". Astronomy and Astrophysics. 623: A72. arXiv:1811.08902. Bibcode:2019A&A...623A..72K. doi:10.1051/0004-6361/201834371. S2CID 119491061.
  7. ^ a b c Tetzlaff, N.; et al. (January 2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1): 190–200. arXiv:1007.4883. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. S2CID 118629873.
  8. ^ a b c d e Arcos, C.; et al. (March 2018). "Stellar parameters and H α line profile variability of Be stars in the BeSOS survey". Monthly Notices of the Royal Astronomical Society. 474 (4): 5287–5299. arXiv:1711.08675. Bibcode:2018MNRAS.474.5287A. doi:10.1093/mnras/stx3075.
  9. ^ "j Cen". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2021-01-28.
  10. ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
  11. ^ Brown, A. G. A.; Verschueren, W. (March 1997). "High S/N Echelle spectroscopy in young stellar groups. II. Rotational velocities of early-type stars in SCO OB2". Astronomy and Astrophysics. 319: 811–838. arXiv:astro-ph/9608089. Bibcode:1997A&A...319..811B.
  12. ^ Hoogerwerf, R.; et al. (January 2001). "On the origin of the O and B-type stars with high velocities. II. Runaway stars and pulsars ejected from the nearby young stellar groups". Astronomy and Astrophysics. 365 (2): 49–77. arXiv:astro-ph/0010057. Bibcode:2001A&A...365...49H. doi:10.1051/0004-6361:20000014. S2CID 18970167.
  13. ^ van Belle, Gerard T. (March 2012). "Interferometric observations of rapidly rotating stars". The Astronomy and Astrophysics Review. 20 (1): 51. arXiv:1204.2572. Bibcode:2012A&ARv..20...51V. doi:10.1007/s00159-012-0051-2. S2CID 119273474.
  14. ^ Arcos, C.; et al. (June 2017). "Evidence for Different Disk Mass Distributions between Early- and Late-type Be Stars in the BeSOS Survey". The Astrophysical Journal. 842 (1): 18. arXiv:1704.08133. Bibcode:2017ApJ...842...48A. doi:10.3847/1538-4357/aa6f5f. S2CID 119418279. 48.
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