Delta2 Chamaeleontis

Delta2 Chamaeleontis, Latinized from δ2 Chamaeleontis, is a solitary[11] star located in the southern circumpolar constellation of Chamaeleon. It has an apparent visual magnitude of 4.42,[2] which is bright enough for the star to seen with the naked eye. Based upon an annual parallax shift of 9.30 mas,[1] it is located around 351 light years from the Sun. This star is one of two stars named Delta Chamaeleontis, the other being the fainter Delta1 Chamaeleontis located about 6 arcminutes away.[12] Delta Chamaeleontis forms the southernmost component of the constellation's "dipper" or bowl. Together with Gamma Chamaeleontis, they point to a spot that is within 2° of the south celestial pole.[13]

For other stars with this Bayer designation, see δ Chamaeleontis.
δ2 Chamaeleontis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Chamaeleon
Right ascension 10h 45m 47.00487s[1]
Declination −80° 32′ 24.6785″[1]
Apparent magnitude (V) 4.42[2]
Characteristics
Spectral type B3 V[3] or B2.5 IV[4]
U−B color index −0.728[2]
B−V color index −0.192[2]
Astrometry
Radial velocity (Rv)+22.6[5] km/s
Proper motion (μ) RA: −36.86[1] mas/yr
Dec.: +5.90[1] mas/yr
Parallax (π)9.30 ± 0.13 mas[1]
Distance351 ± 5 ly
(108 ± 2 pc)
Absolute magnitude (MV)−0.71[6]
Details
Mass5.0±0.1[7] M☉
Radius3.9[8] R☉
Luminosity503[9] L☉
Temperature15,873[9] K
Age32.6±16.3[7] Myr
Other designations
δ2 Cha, CPD−79°556, FK5 411, HIP 52633, HR 4234, SAO 258593[10]
Database references
SIMBADdata

This is a B-type main sequence star with a stellar classification of B3 V.[3] However, Hiltner et al. (1969) give a classification of B2.5 IV,[4] which would suggest it is a more evolved subgiant star. It is estimated to have five[7] times the mass of the Sun and 3.9[8] times the Sun's radius. With an age of 32.6[7] million years, it is radiating over 500 times the solar luminosity from its outer atmosphere at an effective temperature of 15,873[9] K. There is a 70% likelihood that this star is a member of Gould's Belt.[14]

References
  1. 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. Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A photometric investigation of the Scorpio-Centaurus association", Astrophysical Journal Supplement Series, 15: 459, Bibcode:1968ApJS...15..459G, doi:10.1086/190168.
  3. Houk, Nancy (1979), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 1, Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
  4. Hiltner, W. A.; et al. (July 1969), "MK Spectral Types for Bright Southern OB Stars", Astrophysical Journal, 157: 313, Bibcode:1969ApJ...157..313H, doi:10.1086/150069.
  5. Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick (eds.), Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, vol. 30, University of Toronto: International Astronomical Union, p. 57, Bibcode:1967IAUS...30...57E.
  6. 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.
  7. 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. Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) – Third edition – Comments and statistics", Astronomy and Astrophysics, 367 (2): 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451, S2CID 425754.
  9. 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.
  10. "del02 Cha – Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-12-11.
  11. Eggleton, P. P.; Tokovinin, A. A. (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.
  12. Inglis, Michael (2012), Astronomy of the Milky Way: The Observer's Guide to the Southern Milky Way, The Patrick Moore Practical Astronomy Series, Springer Science & Business Media, p. 106, ISBN 978-1447106418.
  13. O'Meara, Stephen James (2002), Deep-Sky Companions: The Caldwell Objects, Cambridge University Press, p. 424, ISBN 0521827965.
  14. Bobylev, V. V.; Bajkova, A. T. (September 2007), "Kinematics of the Scorpius-Centaurus OB association", Astronomy Letters, 33 (9): 571–583, arXiv:0708.0943, Bibcode:2007AstL...33..571B, doi:10.1134/S1063773707090010, S2CID 15785349.
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