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: + 5.220 ± 0.546[5] mas/yr
Dec.: −103.457 ± 0.483[5] mas/yr
Parallax (π)11.0358 ± 0.2918 mas[5]
Distance296 ± 8 ly
(91 ± 2 pc)
Absolute magnitude (MV)−0.62[6] + 8.19[3]
Details
Luminosity147[7] L☉
Surface gravity (log g)3.5[8] cgs
Temperature8,830[7] K
Rotational velocity (v sin i)49[9] km/s
β Crt B
Mass0.43[10] M☉
Radius0.027[3] R☉
Surface gravity (log g)7.40[11] cgs
Temperature36,885[11] K
Other designations
β Crt, 11 Crateris, BD−22° 3095, FK5 421, HD 97277, HIP 54682, HR 4343, SAO 179624, WD 1109-225.[12]
Database references
SIMBADdata

Beta Crateris, Latinized from 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[13] 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][13][10] However, Houk and Smith-Moore (1988) give a main sequence classification of A1 V,[14] while Abt and Morrell (1995) list it as a subgiant star with a class of A2 IV.[15] The spectrum shows enhanced barium, possibly as a result of a previous mass transfer event.[8]

The companion, component B, is a white dwarf[10] of class DA with an effective temperature of 36,885 K that has been cooling down for around four million years.[11] 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.[16]

  1. ^ a b Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Mermilliod1986 was invoked but never defined (see the help page).
  3. ^ a b c d e f g h i Cite error: The named reference Holberg2013 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference deBruijne2012 was invoked but never defined (see the help page).
  5. ^ a b c Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  6. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference Mcdonald2012 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Smalley1997 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Royer2007 was invoked but never defined (see the help page).
  10. ^ a b c Cite error: The named reference Burleigh2001 was invoked but never defined (see the help page).
  11. ^ a b c Cite error: The named reference Barstow2014 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  13. ^ a b Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference houk1978 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference abt1995 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Schroeder2007 was invoked but never defined (see the help page).