Lambda Crateris

Lambda Crateris, Latinized from λ Crateris, is the Bayer designation for a suspected binary star[12] system in the southern constellation of Crater. With an annual parallax shift of 23.32[1] milliarcsecond as observed from Earth, it is located around 140 light years from the Sun. It is faintly visible to the naked eye with an apparent visual magnitude of 5.08.[2]

Lambda Crateris
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Crater
Right ascension 11h 23m 21.88432s[1]
Declination −18° 46′ 47.8910″[1]
Apparent magnitude (V) 5.08[2]
Characteristics
Spectral type F5 III[3]
U−B color index −0.04[2]
B−V color index +0.43[2]
Astrometry
Radial velocity (Rv)+13.26±0.60[4] km/s
Proper motion (μ) RA: −305.37[1] mas/yr
Dec.: +27.56[1] mas/yr
Parallax (π)23.32 ± 0.80[1] mas
Distance140 ± 5 ly
(43 ± 1 pc)
Absolute magnitude (MV)+1.92[5]
Orbit[6]
Period (P)1,940±84 d[7]
Eccentricity (e)0.54
Periastron epoch (T)32722
Argument of periastron (ω)
(secondary)		140.7°
Semi-amplitude (K1)
(primary)		2.5 km/s
Details
Mass1.78[8] M☉
Radius2.8[9] R☉
Luminosity14.4[5] L☉
Surface gravity (log g)4.06±0.11[4] cgs
Temperature6,582±54[4] K
Metallicity [Fe/H]−0.15±0.01[4] dex
Rotational velocity (v sin i)17.0[10] km/s
Other designations
λ Crt, 13 Crateris, BD−17° 3367, HD 98991, HIP 55598, HR 4395, SAO 156646.[11]
Database references
SIMBADdata

This is a probable astrometric binary[12] star system, with orbital elements first reported by Abt and Levy (1976). However, Morbey and Griffin (1987) later cast some doubt on the validity of these results, suggesting that further review is needed.[13] The visible member of this system, component A, is an evolved F-type giant star[10] with a stellar classification of F5 III.[3] It has an estimated 1.78[8] times the mass of the Sun and 2.8[9] times the Sun's radius. The star is spinning with a projected rotational velocity of 17[10] km/s.

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.
  2. Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.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. Abt, Helmut A. (2009), "MK Classifications of Spectroscopic Binaries", The Astrophysical Journal Supplement, 180 (1): 117–18, Bibcode:2009ApJS..180..117A, doi:10.1088/0067-0049/180/1/117.
  4. Kordopatis, G.; et al. (November 2013), "The Radial Velocity Experiment (RAVE): Fourth Data Release", The Astronomical Journal, 146 (5): 36, arXiv:1309.4284, Bibcode:2013AJ....146..134K, doi:10.1088/0004-6256/146/5/134, 134.
  5. 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.
  6. Batten, A. H.; et al. (1978), "Seventh catalogue of the orbital elements of spectroscopic binary systems.", Publications of the Dominion Astrophysical Observatory Victoria, 15: 121−295, Bibcode:1978PDAO...15..121B. See No. 431
  7. Abt, H. A.; Levy, S. G. (March 1976), "Multiplicity among solar-type stars", Astrophysical Journal Supplement Series, 30: 273−306, Bibcode:1976ApJS...30..273A, doi:10.1086/190363.
  8. Tokovinin, Andrei (2014), "From Binaries to Multiples. II. Hierarchical Multiplicity of F and G Dwarfs", The Astronomical Journal, 147 (4): 14, arXiv:1401.6827, Bibcode:2014AJ....147...87T, doi:10.1088/0004-6256/147/4/87, 87.
  9. 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: 521–524, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451.
  10. Schröder, C.; Reiners, A.; Schmitt, J. H. M. M. (January 2009), "Ca II HK emission in rapidly rotating stars. Evidence for an onset of the solar-type dynamo" (PDF), Astronomy and Astrophysics, 493 (3): 1099–1107, Bibcode:2009A&A...493.1099S, doi:10.1051/0004-6361:200810377.
  11. "lam Crt". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-02-26.
  12. 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, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x.
  13. Morbey, C. L.; Griffin, R. F. (June 1, 1987), "On the reality of certain spectroscopic orbits", Astrophysical Journal, Part 1, 317: 343−352, Bibcode:1987ApJ...317..343M, doi:10.1086/165281.
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