56 Sagittarii

56 Sagittarii

Observation data Epoch J2000      Equinox J2000
Constellation	Sagittarius
Right ascension	19^h 46^m 21.73912^s[1]
Declination	−19° 45′ 40.0132″[1]
Apparent magnitude (V)	4.87[2]
Characteristics
Evolutionary stage	horizontal branch[3]
Spectral type	K0+III[4]
U−B color index	+0.96[5]
B−V color index	+1.06[5]
Astrometry
Radial velocity (Rv)	+22.07[6] km/s
Proper motion (μ)	RA: −129.40[1] mas/yr Dec.: −90.55[1] mas/yr
Parallax (π)	15.71 ± 0.23 mas[1]
Distance	208 ± 3 ly (63.7 ± 0.9 pc)
Absolute magnitude (MV)	0.85[2]
Details
Mass	1.77[7] M☉
Radius	11[6] R☉
Luminosity	58.97[2] L☉
Surface gravity (log g)	2.58[8] cgs
Temperature	4,750[9] K
Metallicity [Fe/H]	−0.07[8] dex
Rotational velocity (v sin i)	1.9[6] km/s
Other designations
f Sgr, 56 Sgr, BD−20°5698, GC 27349, HD 186648, HIP 97290, HR 7515, SAO 162964, GSC 06320-02845[10]
Database references
SIMBAD	data

56 Sagittarii is a single[11] star in the southern constellation of Sagittarius. It has the Bayer designation f Sagittarii, while 56 Sagittarii is the Flamsteed designation. This object is visible to the naked eye as a faint, orange-hued point of light with an apparent visual magnitude of 4.87.[2] It is located approximately 208 light years away from the Sun based on parallax,[1] and is drifting further away with a radial velocity of +22 km/s.[6]

This is an aging giant star with a stellar classification of K0+III,[4] having exhausted the supply of hydrogen at its core and expanded to 11[6] times the Sun's radius. It is a red clump giant,[3] which means it is on the horizontal branch and is generating energy through helium fusion at its core. The star has 1.8[7] times the mass of the Sun and is radiating 59[2] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,750 K.[9]

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. S2CID 18759600. Vizier catalog entry
2. 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. Vizier catalog entry
3. Alves, David R. (August 2000), "K-Band Calibration of the Red Clump Luminosity", The Astrophysical Journal, 539 (2): 732–741, arXiv:astro-ph/0003329, Bibcode:2000ApJ...539..732A, doi:10.1086/309278, S2CID 16673121
4. 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.
5. Mermilliod, J. C. (2006). "Homogeneous Means in the UBV System (Mermilliod 1991)". VizieR On-line Data Catalog: II/168. Originally Published in: Institut d'Astronomie. 2168. Bibcode:2006yCat.2168....0M.Vizier catalog entry
6. Massarotti, Alessandro; et al. (January 2008). "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity". The Astronomical Journal. 135 (1): 209–231. Bibcode:2008AJ....135..209M. doi:10.1088/0004-6256/135/1/209. S2CID 121883397.
7. Allende Prieto, C.; Lambert, D. L. (1999). "Fundamental parameters of nearby stars from the comparison with evolutionary calculations: Masses, radii and effective temperatures". Astronomy and Astrophysics. 352: 555–562. arXiv:astro-ph/9911002. Bibcode:1999A&A...352..555A. Vizier catalog entry
8. Wu, Yue; et al. (2010). "Coudé-feed stellar spectral library – atmospheric parameters". Astronomy & Astrophysics. 525: A71. arXiv:1009.1491. Bibcode:2011A&A...525A..71W. doi:10.1051/0004-6361/201015014. S2CID 53480665.
9. Gontcharov, G. A. (2009). "Red giant clump in the Tycho-2 catalogue". Astronomy Letters. 34 (11): 785–796. arXiv:1607.00619. Bibcode:2008AstL...34..785G. doi:10.1134/S1063773708110078. S2CID 73524157. Vizier catalog entry
10. "f Sgr". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-07-27.
11. 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.