61 Leonis
61 Leonis is a possible binary star[10] system in the zodiac constellation of Leo. It is faintly visible to the naked eye, having an apparent visual magnitude of 4.73.[2] The star is moving closer to the Sun with a heliocentric radial velocity of −12.7 km/s.[6] It is located roughly 580 light-years from the Sun, as determined from its annual parallax shift of 5.58 mas.[1]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Leo |
| Right ascension | 11h 01m 49.67462s[1] |
| Declination | −02° 29′ 04.5007″[1] |
| Apparent magnitude (V) | 4.73[2] |
| Characteristics | |
| Evolutionary stage | AGB[3] |
| Spectral type | M0 III[4] |
| B−V color index | +1.593±0.059[2] |
| Variable type | suspected[5] |
| Astrometry | |
| Radial velocity (Rv) | −12.7±0.3[6] km/s |
| Proper motion (μ) | RA: +9.76[1] mas/yr Dec.: −35.56[1] mas/yr |
| Parallax (π) | 5.58 ± 0.24 mas[1] |
| Distance | 580 ± 30 ly (179 ± 8 pc) |
| Absolute magnitude (MV) | −1.53[2] |
| Details | |
| Radius | 74.5[7] R☉ |
| Luminosity | 1,377.86[2] L☉ |
| Surface gravity (log g) | 1.25±0.23[8] cgs |
| Temperature | 3,864±30[8] K |
| Metallicity [Fe/H] | 0.07±0.07[8] dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an evolved red giant star with a stellar classification of M0 III[4] that Eggen (1992) listed as being on the asymptotic giant branch (AGB).[3] It is a marginal barium star, showing an enhanced abundance of s-process elements in its outer atmosphere. This material may have been acquired during a previous mass transfer from a now white dwarf companion, or self-enriched by a dredge-up during the AGB process.[11] The measured angular diameter after correctly for limb darkening is 3.87±0.04 mas,[12] which, at the estimated distance of this system yields a physical size of about 74.5 times the radius of the Sun.[7]
61 Leonis is a suspected variable star with apparent magnitude changing between 4.69 and 4.79.[5] The variability was reported in a 1966 photometric survey, but has not been confirmed by more recent photometry.[13]
References edit
- ^ a b c d e f 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.
- ^ a b c d e 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.
- ^ a b Eggen, O. J. (1992), "Asymptotic giant branch stars near the sun", The Astronomical Journal, 104: 275, Bibcode:1992AJ....104..275E, doi:10.1086/116239.
- ^ a b Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373
- ^ a b Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
- ^ a b 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, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
- ^ a b Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, vol. 1 (3rd ed.), Birkhäuser, ISBN 3-540-29692-1. The radius (R*) is given by:
- ^ a b c Prugniel, Ph.; et al. (2011), "The atmospheric parameters and spectral interpolator for the MILES stars", Astronomy & Astrophysics, 531: A165, arXiv:1104.4952, Bibcode:2011A&A...531A.165P, doi:10.1051/0004-6361/201116769, S2CID 54940439
- ^ "61 Leo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-03-01.
- ^ 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, S2CID 14878976.
- ^ Gomez, A. E.; et al. (1997), "Absolute magnitudes and kinematics of barium stars", Astronomy and Astrophysics, 319: 881, Bibcode:1997A&A...319..881G.
- ^ Richichi, A.; et al. (February 2005), "CHARM2: An updated Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 431 (2): 773–777, Bibcode:2005A&A...431..773R, doi:10.1051/0004-6361:20042039
- ^ A. W. J. Cousins (1966). "Fabry photometry of bright southern stars". Royal Greenwich Observatory Bulletins. 122: 59. Bibcode:1966RGOB..122...59C.