Beta Crateris

β Crateris


Location of β Crateris (circled)

Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Crater
Right ascension 11h 11m 39.48783s[1]
Declination −22° 49′ 33.0593″[1]
Apparent magnitude (V) 4.46[2] (4.61 + 13.40)[3]
Characteristics
Spectral type A2 III[3] + DA1.4[3]
U−B color index +0.05[2]
B−V color index +0.02[2]
Astrometry
Radial velocity (Rv)+5.6±0.5[4] km/s
Proper motion (μ) RA: +2.52[1] mas/yr
Dec.: −100.22[1] mas/yr
Parallax (π)9.59 ± 0.66[1] mas
Distance340 ± 20 ly
(104 ± 7 pc)
Absolute magnitude (MV)? + 8.19[3]
Details
Luminosity147[5] L☉
Surface gravity (log g)3.5[6] cgs
Temperature8,830[5] K
Rotational velocity (v sin i)49[7] km/s
β Crt B
Mass0.43[8] M☉
Radius0.027[3] R☉
Surface gravity (log g)7.40[9] cgs
Temperature36,885[9] K
Other designations
β Crt, 11 Crateris, BD−22° 3095, FK5 421, HD 97277, HIP 54682, HR 4343, SAO 179624, WD 1109-225.[10]
Database references
SIMBADdata

Beta Crateris (β Crt, β Crateris) is a binary star[3] system in the southern constellation of Crater. It is visible to the naked eye with an apparent visual magnitude of 4.46.[2] Based upon an annual parallax shift of 9.59 mas as seen from Earth, it is located around 340 light years from the Sun.

This is an astrometric binary[11] star system with an orbital period of 6.0 years and a projected separation of 8.3 AU. The orbit has an estimated semimajor axis of 9.3 AU.[3] The primary, component A, is listed as an A-type giant star with a stellar classification of A2 III.[3][11][8] However, Houk and Smith-Moore (1988) give a main sequence classification of A1 V,[12] while Abt and Morrell (1995) list it as a subgiant star with a class of A2 IV.[13] The spectrum shows enhanced barium, possibly as a result of a previous mass transfer event.[6]

The companion, component B, is a white dwarf[8] of class DA with an effective temperature of 36,885 K that has been cooling down for around four million years.[9] It has an unusually low mass, 43% that of the Sun, suggesting that the white dwarf progenitor may have transferred matter to its companion. Alternative scenarios require either the evolution of a triple star system, or a binary system with highly eccentric orbit resulting in grazing interactions.[3] The dwarf is a source of X-ray emission.[14]

Name

This star was one of the set assigned by the 16th century astronomer Al Tizini[15] to Al Sharāsīf (ألصرسىف), the Ribs (of Hydra), which included the stars from β Crateris westward through κ Hydrae.[16][17]

In Chinese, 翼宿 (Yì Sù), meaning Wings (asterism), refers to an asterism consisting of β Crateris, α Crateris, γ Crateris, ζ Crateris, λ Crateris, ν Hydrae, η Crateris, δ Crateris, ι Crateris, κ Crateris, ε Crateris, HD 95808, HD 93833, θ Crateris, HD 102574, HD 100219, HD 99922, HD 100307, HD 96819, χ1 Hydrae, HD 102620 and HD 103462.[18] Consequently, β Crateris itself is known as 翼宿十六 (Yì Sù shíliù, English: the Sixteenth Star of Wings.)[19][20]

References

  1. 1 2 3 4 5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752 Freely accessible, doi:10.1051/0004-6361:20078357.
  2. 1 2 3 4 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV data, SIMBAD, Bibcode:1986EgUBV........0M.
  3. 1 2 3 4 5 6 7 8 9 Holberg, J. B.; et al. (2013), "Where are all the Sirius-like binary systems?", Monthly Notices of the Royal Astronomical Society, 435 (3): 2077, Bibcode:2013MNRAS.435.2077H, arXiv:1307.8047 Freely accessible, doi:10.1093/mnras/stt1433.
  4. ↑ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, Bibcode:2012A&A...546A..61D, arXiv:1208.3048 Freely accessible, doi:10.1051/0004-6361/201219219, A61.
  5. 1 2 McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, Bibcode:2012MNRAS.427..343M, arXiv:1208.2037 Freely accessible, doi:10.1111/j.1365-2966.2012.21873.x.
  6. 1 2 Smalley, B.; et al. (January 1997), "The chemical composition and binarity of beta Crateris", Monthly Notices of the Royal Astronomical Society, 284 (2): 457−464, Bibcode:1997MNRAS.284..457S, doi:10.1093/mnras/284.2.457.
  7. ↑ Royer, F.; et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, Bibcode:2007A&A...463..671R, arXiv:astro-ph/0610785 Freely accessible, doi:10.1051/0004-6361:20065224.
  8. 1 2 3 Burleigh, M. R.; et al. (November 2001), "The low-mass white dwarf companion to β Crateris", Monthly Notices of the Royal Astronomical Society, 327 (4): 1158−1164, Bibcode:2001MNRAS.327.1158B, arXiv:astro-ph/0106463 Freely accessible, doi:10.1046/j.1365-8711.2001.04818.x.
  9. 1 2 3 Barstow, M. A.; et al. (May 2014), "Evidence for an external origin of heavy elements in hot DA white dwarfs", Monthly Notices of the Royal Astronomical Society, 440 (2): 1607−1625, Bibcode:2014MNRAS.440.1607B, doi:10.1093/mnras/stu216.
  10. ↑ "bet Crt -- Spectroscopic binary", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-03-02.
  11. 1 2 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, Bibcode:2008MNRAS.389..869E, arXiv:0806.2878 Freely accessible, doi:10.1111/j.1365-2966.2008.13596.x.
  12. ↑ Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988MSS...C04....0H.
  13. ↑ Abt, Helmut A.; Morrell, Nidia I. (1995), "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars", Astrophysical Journal Supplement, 99: 135, Bibcode:1995ApJS...99..135A, doi:10.1086/192182.
  14. ↑ Schröder, C.; Schmitt, J. H. M. M. (November 2007), "X-ray emission from A-type stars", Astronomy and Astrophysics, 475 (2): 677−684, Bibcode:2007A&A...475..677S, doi:10.1051/0004-6361:20077429.
  15. ↑ Rim Turkmani. "Arabic Roots of the Scientific Revolution". Muslim Heritage. Retrieved 1 July 2016.
  16. ↑ Star Names - R.H.Allen p. 182
  17. ↑ Star Names - R.H.Allen p. 246
  18. ↑ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
  19. ↑ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 5 月 31 日
  20. ↑ (in Chinese) 夢之大地 @ 國立成功大學 WebBBS DreamLand @ National Cheng Kung University WebBBS System
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