HD 117566

HD 117566, also known as HR 5091, is a solitary yellow-hued star^[15] located in the northern circumpolar constellation Camelopardalis. It has an apparent magnitude of 5.74,^[2] making it faintly visible to the naked eye. This object is relatively close at a distance of 291 light years based on Gaia DR3 parallax measurements but is receding with a heliocentric radial velocity of 14 km/s.^[7] At its current distance, HD 117566's brightness is diminished by 0.12 magnitudes due to interstellar dust.^[16]

HD 117566

Location of HD 117566 on the map (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Camelopardalis
Right ascension	13h 26m 56.80348s[1]
Declination	+78° 38′ 37.9324″[1]
Apparent magnitude (V)	5.74±0.01[2]
Characteristics
Evolutionary stage	Hertzsprung gap[3] or horizontal branch[4]
Spectral type	G3 IIIb Fe−1 CH1[5]
U−B color index	+0.35[6]
B−V color index	+0.77[6]
Astrometry
Radial velocity (Rv)	13.7±0.3[7] km/s
Proper motion (μ)	RA: −140.497 mas/yr[1] Dec.: +30.403 mas/yr[1]
Parallax (π)	11.1974 ± 0.0417 mas[1]
Distance	291 ± 1 ly (89.3 ± 0.3 pc)
Absolute magnitude (MV)	+1.03[8]
Details
Mass	2.29[9] M☉
Radius	7.2±0.4[10] R☉
Luminosity	38.2±0.3[1] L☉
Surface gravity (log g)	3.69±0.18[11] cgs
Temperature	5,420±26[12] K
Metallicity [Fe/H]	+0.03[11] dex
Rotational velocity (v sin i)	8.9±1[13] km/s
Age	760±50[7] Myr
Other designations
AG+78°340, BD+79°422, FK5 3075, GC 18223, HD 117566, HIP 65595, HR 5091, SAO 7821[14]
Database references
SIMBAD	data

HD 117566 has a stellar classification of G3 IIIb Fe−1 CH1,^[5] indicating that it is a G-type giant with an under-abundance of iron and an overabundance of the CH radical in its spectrum. Its evolutionary stage is unclear. A 1994 paper places it in the Hertzsprung gap,^[3] indicating it has ceased hydrogen core fusion and is now evolving toward the red giant branch (RGB). However, Mishenina et al. (2006) said that HD 117566 is already past the RGB and is on the horizontal branch, fusing helium at its core.^[4] Nevertheless, it has 2.29 times the mass of the Sun^[9] and, at the age of 760 million years,^[7] it has expanded to 7.2 times the Sun's radius.^[10] It radiates 38.2 times the luminosity of the Sun^[1] from its photosphere at an effective temperature of 5,420 K.^[12] HD 117566 has a solar metallicity^[11] and spins modestly with a projected rotational velocity of 9 km/s.^[13]

References

1. 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.
2. Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. ISSN 0004-6361.
3. Wallerstein, George; Bohm-Vitense, Erika; Vanture, Andrew D.; Gonzalez, Guillermo (June 1994). "The lithium content and other properties of F2-G5 giants in the Hertzsprung Gap". The Astronomical Journal. 107: 2211. Bibcode:1994AJ....107.2211W. doi:10.1086/117031. ISSN 0004-6256.
4. Mishenina, T. V.; Bienaymé, O.; Gorbaneva, T. I.; Charbonnel, C.; Soubiran, C.; Korotin, S. A.; Kovtyukh, V. V. (September 2006). "Elemental abundances in the atmosphere of clump giants". Astronomy & Astrophysics. 456 (3): 1109–1120. arXiv:astro-ph/0605615. Bibcode:2006A&A...456.1109M. doi:10.1051/0004-6361:20065141. eISSN 1432-0746. ISSN 0004-6361.
5. Keenan, Philip C.; McNeil, Raymond C. (October 1989). "The Perkins catalog of revised MK types for the cooler stars". The Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373. eISSN 1538-4365. ISSN 0067-0049.
6. Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data. SIMBAD, Bibcode:1986EgUBV........0M
7. Soubiran, C.; Bienaymé, O.; Mishenina, T. V.; Kovtyukh, V. V. (9 January 2008). "Vertical distribution of Galactic disk stars". Astronomy & Astrophysics. 480 (1): 91–101. arXiv:0712.1370. Bibcode:2008A&A...480...91S. doi:10.1051/0004-6361:20078788. eISSN 1432-0746. ISSN 0004-6361.
8. 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.
9. Liu, Y. J.; Tan, K. F.; Wang, L.; Zhao, G.; Sato, Bun'ei; Takeda, Y.; Li, H. N. (31 March 2014). "The Lithium Abundances of a Large Sample of Red Giants". The Astrophysical Journal. 785 (2): 94. arXiv:1404.1687. Bibcode:2014ApJ...785...94L. doi:10.1088/0004-637X/785/2/94. eISSN 1538-4357. ISSN 0004-637X.
10. Kervella, P.; Thévenin, F.; Di Folco, E.; Ségransan, D. (October 2004). "The angular sizes of dwarf stars and subgiants". Astronomy & Astrophysics. 426 (1): 297–307. arXiv:astro-ph/0404180. Bibcode:2004A&A...426..297K. doi:10.1051/0004-6361:20035930. eISSN 1432-0746. ISSN 0004-6361.
11. da Silva, Ronaldo; Milone, André de C.; Rocha-Pinto, Helio J. (August 2015). "Homogeneous abundance analysis of FGK dwarf, subgiant, and giant stars with and without giant planets". Astronomy and Astrophysics. 580: A24. arXiv:1505.01726. Bibcode:2015A&A...580A..24D. doi:10.1051/0004-6361/201525770. ISSN 0004-6361.
12. Strassmeier, K.G.; Schordan, P. (December 2000). "A temperature calibration for MK-class III giants from high-resolution spectral line-depth ratios". Astronomische Nachrichten. 321 (5–6): 277–305. Bibcode:2000AN....321..277S. doi:10.1002/1521-3994(200012)321:5/6<277::AID-ASNA277>3.0.CO;2-H. eISSN 1521-3994. ISSN 0004-6337.
13. De Medeiros, J. R.; Alves, S.; Udry, S.; Andersen, J.; Nordström, B.; Mayor, M. (January 2014). "A catalog of rotational and radial velocities for evolved stars". Astronomy & Astrophysics. 561: A126. arXiv:1312.3474. Bibcode:2014A&A...561A.126D. doi:10.1051/0004-6361/201220762. eISSN 1432-0746. ISSN 0004-6361.
14. "HD 117566". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved December 16, 2022.
15. 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.
16. Gontcharov, George A.; Mosenkov, Aleksandr V. (28 September 2017). "Verifying reddening and extinction for Gaia DR1 TGAS main sequence stars". Monthly Notices of the Royal Astronomical Society. 472 (4): 3805–3820. arXiv:1709.01160. Bibcode:2017MNRAS.472.3805G. doi:10.1093/mnras/stx2219. eISSN 1365-2966. ISSN 0035-8711.