Astronomy:Beta Chamaeleontis

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Short description: Star in the constellation Chamaeleon
Beta Chamaeleontis
Location of β Chamaeleontis (circled in red)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Chamaeleon[1]
Right ascension  12h 18m 20.82459s[2]
Declination −79° 18′ 44.0710″[2]
Apparent magnitude (V) 4.24[3] (4.24 to 4.30)[4]
Characteristics
Evolutionary stage main sequence[5]
Spectral type B4 V[6] or B5 IV[7]
U−B color index −0.52[3]
B−V color index −0.13[3]
R−I color index −0.10[8]
Variable type SPB[7]
Astrometry
Radial velocity (Rv)+23.0[9] km/s
Proper motion (μ) RA: −37.97[2] mas/yr
Dec.: +11.15[2] mas/yr
Parallax (π)10.93 ± 0.15[2] mas
Distance298 ± 4 ly
(91 ± 1 pc)
Absolute magnitude (MV)−0.57[1]
Details
Mass5.0±0.1[10] M☉
Radius2.84±0.13[11] R☉
Luminosity212[12] L☉
Surface gravity (log g)4.03±0.05[11] cgs
Temperature14,495±157[11] K
Rotational velocity (v sin i)255[8] km/s
Age22.7±7.2[10] Myr
Other designations
β Cha, CD−78°495, CPD−78°741, FK5 459, GC 16775, HD 106911, HIP 60000, HR 4674, SAO 256924, PPM 371459[13]
Database references
SIMBADdata

Beta Chamaeleontis is the third-brightest star in the southern constellation of Chamaeleon. Its name is a Bayer designation that is Latinized from β Chamaeleontis, and abbreviated Beta Cha or β Cha. A solitary,[14] suspected variable star,[4] 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.[4] Parallax measurements yield a distance estimate of 298 light-years (91 pc) from the Sun. It is drifting further away with a radial velocity of +23 km/s.[9]

This is a B-type main-sequence star with a stellar classification of B4 V[6] that is generating energy through core hydrogen fusion. It has been catalogued both as a Be star[3] and a normal star.[15] Based on pulsation measurements made by the TESS space telescope, this is a slowly pulsating B-type variable.[7]

Beta Chamaeleontis is about 23[10] million years old with a high projected rotational velocity of 255 km/s.[8] The rapid rotation is creating an equatorial bulge that is 12% larger than the polar radius.[16] The star has five[10] times the mass of the Sun and 2.8[11] times the Sun's radius. It is radiating 212[12] times the luminosity of the Sun from its photosphere at an effective temperature of 14,495 K.[11]

References

  1. ↑ 1.0 1.1 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 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. 
  3. ↑ 3.0 3.1 3.2 3.3 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. 
  4. ↑ 4.0 4.1 4.2 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. 
  5. ↑ 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.
  6. ↑ 6.0 6.1 Houk, N.; Cowley, A. P. (1975), "Catalogue of two-dimensional spectral types for the HD stars", University of Michigan I, Bibcode: 1975mcts.book.....H 
  7. ↑ 7.0 7.1 7.2 Balona, L. A.; Ozuyar, D. (2020), "Pulsation among TESS a and B stars and the Maia variables", Monthly Notices of the Royal Astronomical Society 493 (4): 5871, doi:10.1093/mnras/staa670, Bibcode: 2020MNRAS.493.5871B. 
  8. ↑ 8.0 8.1 8.2 Hoffleit, D.; Warren, Jr., W. H., "HR 4674, database entry", The Bright Star Catalogue (Centre de Données astronomiques de Strasbourg), http://webviz.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=V/50/catalog&recno=4674, retrieved September 5, 2008.  ID V/50.
  9. ↑ 9.0 9.1 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. 
  10. ↑ 10.0 10.1 10.2 10.3 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 
  11. ↑ 11.0 11.1 11.2 11.3 11.4 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 
  12. ↑ 12.0 12.1 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. 
  13. ↑ "bet Cha". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=bet+Cha. 
  14. ↑ 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. 
  15. ↑ 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 
  16. ↑ 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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