Astronomy:HD 102776

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Short description: Binary star system in the constellation Centaurus
HD 102776
Location of j Centauri (circled in red)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Centaurus[1]
Right ascension  11h 49m 41.06733s[2]
Declination −63° 47′ 18.5007″[2]
Apparent magnitude (V) 4.30[1] (+4.30 - 4.39)[3]
Characteristics
Evolutionary stage main sequence[2]
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[1] km/s
Proper motion (μ) RA: −22.022[2] mas/yr
Dec.: +2.755[2] mas/yr
Parallax (π)4.5957 ± 0.3290[2] mas
Distance710 ± 50 ly
(220 ± 20 pc)
Absolute magnitude (MV)−1.98[1]
Details
Mass5.955 M☉[5]
7.2±0.1[6] M☉
Radius5.00±0.10[7] R☉
Luminosity1,342[1] L☉
Surface gravity (log g)3.20±0.03[7] cgs
Temperature20,000±200[7] K
Rotational velocity (v sin i)200±4[7] km/s
Age31.6±0.6[6] Myr
Other designations
j Cen, NSV 5357, CPD−63°1988, FK5 2944, GC 16201, HD 102776, HIP 57669, HR 4537, SAO 251602[8]
Database references
SIMBADdata

HD 102776, also known by its Bayer designation j Centauri, is a suspected astrometric binary[9] 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.[1] The distance to this star is approximately 710 light years based on parallax,[2] and it is drifting further away with a radial velocity of ~29 km/s.[1] It is a member of the Lower Centaurus Crux subgroup of the Sco OB2 association.[10] 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.[11]

A light curve for HD 102776, plotted from Hipparcos data[12]

The stellar classification of the visible component is B3V,[4] matching a B-type main-sequence star. It is around 32[6] million years old and is spinning rapidly with estimates of its projected rotational velocity ranging from 200[7] up to 270 km/s, 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. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A  XHIP record for this object at VizieR.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 3.2 "NSV 5357". American Association of Variable Star Observers. https://www.aavso.org/vsx/index.php?view=detail.top&oid=43981. 
  4. ↑ 4.0 4.1 Houk, Nancy (1979). Michigan catalogue of two-dimensional spectral types for the HD stars. 1. Ann Arbor, Michigan: Department of Astronomy, University of Michigan. Bibcode: 1978mcts.book.....H. 
  5. ↑ 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. doi:10.1051/0004-6361/201834371. Bibcode: 2019A&A...623A..72K. 
  6. ↑ 6.0 6.1 6.2 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. doi:10.1111/j.1365-2966.2010.17434.x. Bibcode: 2011MNRAS.410..190T. 
  7. ↑ 7.0 7.1 7.2 7.3 7.4 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. doi:10.1093/mnras/stx3075. Bibcode: 2018MNRAS.474.5287A. 
  8. ↑ "j Cen". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=j+Cen. 
  9. ↑ 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. doi:10.1111/j.1365-2966.2008.13596.x. Bibcode: 2008MNRAS.389..869E. 
  10. ↑ 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. Bibcode: 1997A&A...319..811B. 
  11. ↑ 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. doi:10.1051/0004-6361:20000014. Bibcode: 2001A&A...365...49H. 
  12. ↑ EAS (1997). "The HIPPARCOS and TYCHO catalogues". Astrometric and Photometric Star Catalogues Derived from the ESA Hipparcos Space Astrometry Mission. ESA SP Series (Noordwijk, Netherlands: ESA Publications Division) 1200. ISBN 9290923997. Bibcode: 1997ESASP1200.....E. https://cdsarc.cds.unistra.fr/viz-bin/ftp-index?/ftp/cats/more/HIP/cdroms/cats. Retrieved 23 September 2024. 
  13. ↑ van Belle, Gerard T. (March 2012). "Interferometric observations of rapidly rotating stars". The Astronomy and Astrophysics Review 20 (1): 51. doi:10.1007/s00159-012-0051-2. Bibcode: 2012A&ARv..20...51V. 
  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. doi:10.3847/1538-4357/aa6f5f. 48. Bibcode: 2017ApJ...842...48A. 



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