106 Herculis

106 Herculis is a variable star in the northern constellation Hercules. It is visible to the naked eye as a faint, red-hued point of light with a baseline apparent visual magnitude of 4.96.[2] Based on its parallax, it is estimated to lie 383 light-years (117 parsecs) away from the Sun.[3] The star is moving closer to the Earth with a heliocentric radial velocity of -35 km/s.[7]

106 Herculis

Observation data Epoch J2000      Equinox J2000
Constellation	Hercules
Right ascension	18^h 20^m 17.91482^s[1]
Declination	+21° 57′ 40.6622″[1]
Apparent magnitude (V)	4.96[2]
Characteristics
Spectral type	M0 III[3]
U−B color index	+1.98[4]
B−V color index	+1.58[4]
Variable type	suspected SR[5][6]
Astrometry
Radial velocity (Rv)	−35.20±0.29[7] km/s
Proper motion (μ)	RA: +18.105[1] mas/yr Dec.: -59.631[1] mas/yr
Parallax (π)	8.5067 ± 0.1739[1] mas
Distance	383 ± 8 ly (118 ± 2 pc)
Absolute magnitude (MV)	−0.664[7]
Details
Radius	44.32+2.70 −5.89[1] R☉
Luminosity	414.1±9.7[1] L☉
Surface gravity (log g)	1.56±0.09[3] cgs
Temperature	3,789±6[3] K
Metallicity [Fe/H]	0.00±0.03[3] dex
Rotational velocity (v sin i)	5.0±1.0[8] km/s
Other designations
106 Her, NSV 24405, BD+21°3390, HD 168720, HIP 89861, HR 6868, SAO 85941[9]
Database references
SIMBAD	data

Eggleton and Tokovinin (2008) listed this as a suspected binary star system consisting of two roughly equal components.[10] It appears as an ageing red giant with a stellar classification of M0III. This is a suspected semiregular variable star with a very small amplitude and a period of 40 days or more.[6] Having exhausted the supply of hydrogen at its core, it has expanded to 44[1] times the Sun's radius. It is radiating around 414[1] times the luminosity of the Sun from its enlarged photosphere at an effective temperature of about 3,789 K.[3]

References

1. 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.
2. J. R., Ducati (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. 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.
4. Mermilliod, J.-C. (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode:1986EgUBV........0M.
5. 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: B/gcvs. Bibcode:2009yCat....102025S.
6. Percy, John R. (1993). "The photometric variability of K giants". Publications of the Astronomical Society of the Pacific. 105: 1422. Bibcode:1993PASP..105.1422P. doi:10.1086/133324.
7. Soubiran, C.; Bienaymé, O.; Mishenina, T. V.; Kovtyukh, V. V. (2008). "Vertical distribution of Galactic disk stars". Astronomy & Astrophysics. 480: 91. arXiv:0712.1370. Bibcode:2008A&A...480...91S. doi:10.1051/0004-6361:20078788.
8. Zamanov, R. K.; et al. (October 2008). "Rotational velocities of the giants in symbiotic stars - III. Evidence of fast rotation in S-type symbiotics". Monthly Notices of the Royal Astronomical Society. 390 (1): 377–382. arXiv:0807.3817. Bibcode:2008MNRAS.390..377Z. doi:10.1111/j.1365-2966.2008.13751.x.
9. "106 Her". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-06-17.
10. 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.