Astronomy:Beta Chamaeleontis
| Observation data 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[1] mas |
| Distance | 298 ± 4 ly (91 ± 1 pc) |
| Absolute magnitude (MV) | −0.57[7] |
| Details | |
| Mass | 5.0±0.1[8] M☉ |
| Radius | 2.84±0.13[9] R☉ |
| Luminosity | 212[10] L☉ |
| Surface gravity (log g) | 4.03±0.05[9] cgs |
| Temperature | 14,495±157[9] K |
| Rotational velocity (v sin i) | 255[5] km/s |
| Age | 22.7±7.2[8] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
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
- ↑ 1.0 1.1 1.2 1.3 1.4 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 2.3 Feinstein, A.; Marraco, H. G. (November 1979), "The photometric behavior of Be Stars", Astronomical Journal 84: 1713–1725, doi:10.1086/112600, Bibcode: 1979AJ.....84.1713F.
- ↑ 3.0 3.1 Samus', N. N et al. (2017), "General catalogue of variable stars", Astronomy Reports, 5.1 61 (1): 80, doi:10.1134/S1063772917010085, Bibcode: 2017ARep...61...80S.
- ↑ 4.0 4.1 Houk, N.; Cowley, A. P. (1975), "Catalogue of two-dimensional spectral types for the HD stars", University of Michigan I, Bibcode: 1975mcts.book.....H
- ↑ 5.0 5.1 5.2 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.
- ↑ 6.0 6.1 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 (Astronomisches Rechen-Institut Heidelberg) 35 (35): 1, Bibcode: 1999VeARI..35....1W.
- ↑ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 8.0 8.1 8.2 8.3 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
- ↑ 9.0 9.1 9.2 9.3 9.4 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, doi:10.1086/427855, Bibcode: 2005AJ....129.1642F
- ↑ 10.0 10.1 McDonald, I. et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society 427 (1): 343–57, doi:10.1111/j.1365-2966.2012.21873.x, Bibcode: 2012MNRAS.427..343M.
- ↑ "bet Cha". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=bet+Cha.
- ↑ 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.
- ↑ Grady, C. A. et al. (September 1987), "Highly Ionized Stellar Winds in Be Stars: The Evidence for Aspect Dependence", Astrophysical Journal 320: 376, doi:10.1086/165551, Bibcode: 1987ApJ...320..376G
- ↑ 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.
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