DR Chamaeleontis

DR Chamaeleontis (DR Cha), also known as HD 93237, is a star located in the southern circumpolar constellation Chamaeleon. The system has an average apparent magnitude of 5.97,[3] allowing it to be faintly visible to the naked eye. DR Cha is located relatively far at a distance of 1,060 light years based on Gaia DR3 parallax measurements,[2] but is receding with a poorly constrained heliocentric radial velocity of 18 km/s.[9]

DR Chamaeleontis

A light curve for DR Chamaeleontis, plotted from TESS data[1]
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Chamaeleon
Right ascension 10h 41m 51.52042s[2]
Declination −79° 46′ 59.8372″[2]
Apparent magnitude (V) 5.97[3] (5.97 - 6.06)[4]
Characteristics
Spectral type B5 IV[5] or B5 III[6]
U−B color index −0.51[7]
B−V color index −0.07[7]
Variable type Eclipsing binary[8]
Astrometry
Radial velocity (Rv)18±10[9] km/s
Proper motion (μ) RA: −16.877 mas/yr[2]
Dec.: +6.079 mas/yr[2]
Parallax (π)3.0765 ± 0.0439 mas[2]
Distance1,060 ± 20 ly
(325 ± 5 pc)
Absolute magnitude (MV)−1.28[10]
Details
Mass6±0.1[11] M☉
Radius6.48[12] R☉
Luminosity (bolometric)1,587[13] L☉
Surface gravity (log g)3.44[14] cgs
Temperature12,039±190[15] K
Metallicity [Fe/H]+0.08[14] dex
Rotational velocity (v sin i)70±7[16] km/s
Age50±11[11] Myr
Other designations
24 G. Chamaeleontis[17], DR Cha, CD−79°439, CPD−79°548, GC 14758, HD 93237, HIP 52340, HR 4206, SAO 256745[18]
Database references
SIMBADdata

The visible component has been given several spectral classes over the years. It has been given a luminosity class of a giant star (III),[6] a subgiant (IV),[5] a dwarf star (V),[19] and emission lines. Most sources generally agree that DR Cha is a B5 star. It has 6 times the mass of the Sun[11] and 6.48 times its girth.[12] It shines with a bolometric luminosity 1,587 times that of the Sun[13] from its photosphere at an effective temperature of 12,039 K,[15] giving it a blue hue. The object is estimated to be 50 million years old[11] and spins modestly with a projected rotational velocity of 70 km/s.[16]

In 1982, M. Jaschek listed DR Cha in a catalog of Be stars.[20] It has been classified as an Algol-type eclipsing binary, having a period of 19.4436 days.[4] However in 2022, Labadie-Bartz et al. examined the TESS data for this star, and found that the primary and secondary eclipses are separated by "about 20 days", which suggests that the 19.4436 day period published earlier may represent the time interval between primary and secondary eclipse, rather than the full orbital period.[21]

References
  1. "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  2. Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  3. Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. ISSN 0004-6361.
  4. Watson, C. L.; Henden, A. A.; Price, A. (May 2006). "The International Variable Star Index (VSX)". Society for Astronomical Sciences Annual Symposium. 25: 47. Bibcode:2006SASS...25...47W.
  5. Hiltner, W. A.; Garrison, R. F.; Schild, R. E. (July 1969). "MK Spectral Types for Bright Southern OB Stars". The Astrophysical Journal. 157: 313. Bibcode:1969ApJ...157..313H. doi:10.1086/150069. eISSN 1538-4357. ISSN 0004-637X.
  6. Houk, N.; Cowley, A. P. (1975). University of Michigan Catalogue of two-dimensional spectral types for the HD stars. Volume I. Declinations −90° to −53°. Bibcode:1975mcts.book.....H.
  7. Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99–110. Bibcode:1966CoLPL...4...99J.
  8. Samus’, N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (January 2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. eISSN 1562-6881. ISSN 1063-7729. S2CID 125853869.
  9. Kharchenko, N.V.; Scholz, R.-D.; Piskunov, A.E.; Röser, S.; Schilbach, E. (November 2007). "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ~55000 stars and mean radial velocities of 516 Galactic open clusters and associations". Astronomische Nachrichten. 328 (9): 889–896. arXiv:0705.0878. Bibcode:2007AN....328..889K. doi:10.1002/asna.200710776. eISSN 1521-3994. ISSN 0004-6337. S2CID 119323941.
  10. Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331–346. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. eISSN 1562-6873. ISSN 1063-7737. S2CID 119257644.
  11. Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (October 12, 2010). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. Oxford University Press (OUP). 410 (1): 190–200. arXiv:1007.4883. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. ISSN 0035-8711.
  12. Kervella, Pierre; Arenou, Frédéric; Thévenin, Frédéric (20 December 2021). "Stellar and substellar companions from Gaia EDR3". Astronomy & Astrophysics. 657: A7. arXiv:2109.10912. Bibcode:2022A&A...657A...7K. doi:10.1051/0004-6361/202142146. eISSN 1432-0746. ISSN 0004-6361.
  13. Hohle, M.M.; Neuhäuser, R.; Schutz, B.F. (April 2010). "Masses and luminosities of O- and B-type stars and red supergiants". Astronomische Nachrichten. 331 (4): 349–360. arXiv:1003.2335. Bibcode:2010AN....331..349H. doi:10.1002/asna.200911355. eISSN 1521-3994. ISSN 0004-6337. S2CID 111387483.
  14. Anders, F.; et al. (August 2019). "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18". Astronomy & Astrophysics. 628: A94. arXiv:1904.11302. Bibcode:2019A&A...628A..94A. doi:10.1051/0004-6361/201935765. eISSN 1432-0746. ISSN 0004-6361.
  15. Stassun, Keivan G.; et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467. eISSN 1538-3881. hdl:1721.1/124721. S2CID 166227927.
  16. Yudin, R. V. (March 2001). "Statistical analysis of intrinsic polarization, IR excess and projected rotational velocity distributions of classical Be stars". Astronomy & Astrophysics. 368 (3): 912–931. Bibcode:2001A&A...368..912Y. doi:10.1051/0004-6361:20000577. eISSN 1432-0746. ISSN 0004-6361.
  17. Gould, Benjamin Apthorp (1878). "Uranometria Argentina : brillantez y posicion de las estrellas fijas, hasta la septima magnitud, comprendidas dentro de cien grados del polo austral : con atlas". Resultados del Observatorio Nacional Argentino. 1. Bibcode:1879RNAO....1.....G.
  18. "DR Cha". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved November 3, 2022.
  19. Morris, P. M. (1 April 1961). "The Scorpio-Centaurus Association: II. Spectral Types and Luminosities of 220 O, B and a Stars". Monthly Notices of the Royal Astronomical Society. 122 (4): 325–334. Bibcode:1961MNRAS.122..325M. doi:10.1093/mnras/122.4.325. eISSN 1365-2966. ISSN 0035-8711.
  20. Jaschek, M.; Egret, D. (April 1982). "Catalog of Be stars". Be Stars. 98: 261–263. Bibcode:1982IAUS...98..261J. doi:10.1007/978-94-009-8565-0_44. ISBN 978-90-277-1367-4.
  21. Labadie-Bartz, Jonathan; Carciofi, Alex C.; Henrique de Amorim, Tajan; Rubio, Amanda; Figueiredo, André Luiz; Ticiani dos Santos, Pedro; Thomson-Paressant, Keegan (May 2022). "Classifying Be Star Variability With TESS. I. The Southern Ecliptic". The Astronomical Journal. 163 (5): 226. Bibcode:2022AJ....163..226L. doi:10.3847/1538-3881/ac5abd.
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