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Beta Chamaeleontis

Beta Chamaeleontis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Chamaeleon
Right ascension 12h 18m 20.82459s[1]
Declination −79° 18′ 44.0710″[1]
Apparent magnitude (V) 4.24[2] (4.24 to 4.30)[3]
Characteristics
Spectral type B4 V[4]
U−B color index −0.52[2]
B−V color index −0.13[2]
R−I color index −0.10[5]
Astrometry
Radial velocity (Rv)+23.0[6] km/s
Proper motion (μ) RA: −37.97[1] mas/yr
Dec.: +11.15[1] mas/yr
Parallax (π)10.93 ± 0.15 mas[1]
Distance298 ± 4 ly
(91 ± 1 pc)
Absolute magnitude (MV)−0.57[7]
Details
Mass5.0±0.1[8] M☉
Radius2.84±0.13[9] R☉
Luminosity212[10] L☉
Surface gravity (log g)4.03±0.05[9] cgs
Temperature14,495±157[9] K
Rotational velocity (v sin i)255[5] km/s
Age22.7±7.2[8] Myr
Other designations
α Oct, CD−78°495, CPD−78°741, FK5 459, GC 16775, HD 106911, HIP 60000, HR 4674, SAO 256924, PPM 371459[11]
Database references
SIMBADdata

Beta Chamaeleontis, Latinized from β Chamaeleontis, is the third-brightest star in the southern constellation of Chamaeleon. A solitary,[12] suspected variable star, it is visible to the naked eye as a faint blue-white point of light with an apparent visual magnitude that has been measured ranging between 4.24 and 4.30.[3] Parallax measurements yield a distance estimate of 298 light years from the Sun, and it is drifting further away with a radial velocity of +23 km/s.[6]

This is a B-type main-sequence star with a stellar classification of B4 V[4] that is generating energy through core hydrogen fusion. It has been catalogued both as a Be star[2] and a normal star.[13] This object is about 23[8] million years old with a high projected rotational velocity of 255 km/s.[5] The rapid rotation is creating an equatorial bulge that is 12% larger than the polar radius.[14] The star has five[8] times the mass of the Sun and 2.8[9] times the Sun's radius. It is radiating 212[10] times the luminosity of the Sun from its photosphere at an effective temperature of 14,495 K.[9]

References

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  1. ^ a b c d e 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.
  2. ^ a b c d Feinstein, A.; Marraco, H. G. (November 1979), "The photometric behavior of Be Stars", Astronomical Journal, 84: 1713–1725, Bibcode:1979AJ.....84.1713F, doi:10.1086/112600.
  3. ^ a b Samus', N. N; et al. (2017), "General catalogue of variable stars", Astronomy Reports, 5.1, 61 (1): 80, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
  4. ^ a b Houk, N.; Cowley, A. P. (1975), "Catalogue of two-dimensional spectral types for the HD stars", University of Michigan, I, Bibcode:1975mcts.book.....H
  5. ^ a b c HR 4674, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line September 5, 2008.
  6. ^ a b Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veroeffentlichungen des Astronomischen Rechen-Instituts Heidelberg, 35 (35), Astronomisches Rechen-Institut Heidelberg: 1, Bibcode:1999VeARI..35....1W.
  7. ^ 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.
  8. ^ a b c d 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
  9. ^ a b c d e Fitzpatrick, E. L.; Massa, D. (March 2005), "Determining the Physical Properties of the B Stars. II. Calibration of Synthetic Photometry", The Astronomical Journal, 129 (3): 1642–1662, arXiv:astro-ph/0412542, Bibcode:2005AJ....129.1642F, doi:10.1086/427855, S2CID 119512018
  10. ^ a b McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
  11. ^ "bet Cha". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-12-10.{{cite web}}: CS1 maint: postscript (link)
  12. ^ 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.
  13. ^ Grady, C. A.; et al. (September 1987), "Highly Ionized Stellar Winds in Be Stars: The Evidence for Aspect Dependence", Astrophysical Journal, 320: 376, Bibcode:1987ApJ...320..376G, doi:10.1086/165551
  14. ^ 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.