HD 85951

HD 85951 (HR 3923), formally named Felis /ˈfiːlɪs/,^[13] is a solitary^[14] orange hued star in the constellation Hydra. It has an apparent magnitude of 4.94,^[2] making it faintly visible to the naked eye under ideal conditions. Based on parallax measurements, the object is about 570 light-years away from the Sun^[1] and is receding with a heliocentric radial velocity of 50 km/s.^[5]

HD 85951

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Hydra
Right ascension	09h 54m 52.2045s[1]
Declination	−19° 00′ 33.620″[1]
Apparent magnitude (V)	4.94[2]
Characteristics
Evolutionary stage	AGB[3]
Spectral type	K5 III[4]
U−B color index	+1.93[2]
B−V color index	+1.57[2]
Astrometry
Radial velocity (Rv)	50±4.2[5] km/s
Proper motion (μ)	RA: −45.386 mas/yr[1] Dec.: −40.456 mas/yr[1]
Parallax (π)	5.6789 ± 0.2214 mas[1]
Distance	570 ± 20 ly (176 ± 7 pc)
Absolute magnitude (MV)	−1.43[6]
Details
Mass	6.40+1.2 −0.4[7] M☉
Radius	56.7[8] R☉
Luminosity	721±32[9] L☉
Surface gravity (log g)	1.3±0.04[10] cgs
Temperature	3,875±39[10] K
Metallicity [Fe/H]	−0.18±0.07[10] dex
Other designations
Felis, 183 G. Hydrae[11], BD−18° 2810, FK5 373, GC 13644, HIP 48615, HR 3923, SAO 155588[12]
Database references
SIMBAD	data

Nomenclature

HD 85951 was the brightest star in the now-obsolete constellation of Felis.^[15] In 2016, the IAU organized a Working Group on Star Names (WGSN)^[16] to catalog and standardize proper names for stars. The WGSN approved the name Felis for this star on 1 June 2018 and it is now so included in the List of IAU-approved Star Names.^[13]

Properties

This an evolved red giant with a stellar classification of K5 III.^[4] It is currently on the asymptotic giant branch,^[3] generating energy via fusion of hydrogen and helium shells around an inert carbon core. At present Felis has 6.4 times the mass of the Sun^[7] and due to its evolved status, has an enlarged radius of 56.7 R_☉.^[8] It radiates at a bolometric luminosity 721 times that of the Sun^[9] from its photosphere at an effective temperature of 3,875 K.^[10] Felis has an iron abundance 66% that of the Sun, making it metal deficient.

References

1. Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
2. Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
3. Eggen, Olin J. (July 1992). "Asymptotic giant branch stars near the sun". The Astronomical Journal. 104: 275. Bibcode:1992AJ....104..275E. doi:10.1086/116239. ISSN 0004-6256.
4. Houk, N.; Smith-Moore, M. (1988). Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Volume 4, Declinations -26° to -12°. Vol. 4. Bibcode:1988mcts.book.....H.
5. Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. eISSN 1562-6873. ISSN 1063-7737. S2CID 119231169.
6. 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.
7. 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.
8. 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. ISSN 0004-6256.
9. 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.
10. Arentsen, Anke; Prugniel, Philippe; Gonneau, Anais; Lançon, Ariane; Trager, Scott; Peletier, Reynier; Lyubenova, Mariya; Chen, Yan-Ping; Falcón Barroso, Jesús; Sánchez Blázquez, Patricia; Vazdekis, Alejandro (July 2019). "Stellar atmospheric parameters for 754 spectra from the X-shooter Spectral Library". Astronomy & Astrophysics. 627: A138. arXiv:1907.06391. Bibcode:2019A&A...627A.138A. doi:10.1051/0004-6361/201834273. eISSN 1432-0746. ISSN 0004-6361.
11. Gould, Benjamin Apthorp (January 1879). "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.
12. "HD 85951". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 30 September 2012.
13. "Naming Stars". IAU.org. Retrieved 18 June 2018.
14. Eggleton, P. P.; Tokovinin, A. A. (11 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. eISSN 1365-2966. ISSN 0035-8711.
15. "Star Tales Felis". Retrieved 16 January 2021.
16. "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.