71 Ophiuchi

71 Ophiuchi is a single[8] star in the equatorial constellation of Ophiuchus. It is visible to the naked eye as a faint, yellow-hued point of light with an apparent visual magnitude of 4.64.[2] The star is located approximately 273 light years away from the Sun based on parallax,[9] and is moving closer with a radial velocity of −3 km/s.[5]

71 Ophiuchi
Location of 71 Ophiuchi (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Ophiuchus
Right ascension 18h 07m 18.35888s[1]
Declination +08° 44′ 01.9181″[1]
Apparent magnitude (V) 4.64[2]
Characteristics
Spectral type G8III[3]
U−B color index +0.73[4]
B−V color index +0.97[4]
Astrometry
Radial velocity (Rv)−3.00±0.09[5] km/s
Proper motion (μ) RA: +9.857[1] mas/yr
Dec.: +29.770[1] mas/yr
Parallax (π)13.1352 ± 0.1891[1] mas
Distance248 ± 4 ly
(76 ± 1 pc)
Absolute magnitude (MV)0.03[2]
Details[6]
Mass2.87±0.09 M☉
Radius12.55+0.27
−0.34[1] R☉
Luminosity88.8±1.5[1] L☉
Surface gravity (log g)3.00±0.02 cgs
Temperature5,001+70
−52[1] K
Metallicity [Fe/H]0.10±0.01 dex
Rotational velocity (v sin i)0.32±0.45 km/s
Age400±30 Gyr
Other designations
71 Oph, BD+08°3582, GC 24693, HD 165760, HIP 88765, HR 6770, SAO 123140[7]
Database references
SIMBADdata

At the estimated age of 400 million years,[6] this is an aging giant star with a stellar classification of G8III,[3] having exhausted the supply of hydrogen at its core and expanded to around 13[1] times the Sun's radius. It is a red clump giant,[10] which means it is on the horizontal branch and is generating energy through helium fusion at its core. The star has 2.9 times the mass of the Sun and is radiating 89 times the Sun's luminosity from its swollen photosphere at an effective temperature of 5,001 K.[6]

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. 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. Hoffleit, D.; Warren, W. H. (1995). "VizieR Online Data Catalog: Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991)". VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H. 5050. Bibcode:1995yCat.5050....0H.
  4. Mallama, A. (2014). "Sloan Magnitudes for the Brightest Stars". The Journal of the American Association of Variable Star Observers. 42 (2): 443. Bibcode:2014JAVSO..42..443M.Vizier catalog entry
  5. Jofré, E.; Petrucci, R.; Saffe, C.; Saker, L.; Artur de la Villarmois, E.; Chavero, C.; Gómez, M.; Mauas, P. J. D. (2015). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets". Astronomy & Astrophysics. 574: A50. arXiv:1410.6422. Bibcode:2015A&A...574A..50J. doi:10.1051/0004-6361/201424474. S2CID 53666931. Vizier catalog entry
  6. Jofré, E.; et al. (2015). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets". Astronomy & Astrophysics. 574: A50. arXiv:1410.6422. Bibcode:2015A&A...574A..50J. doi:10.1051/0004-6361/201424474. S2CID 53666931. A50.
  7. "71 Oph". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-06-21.
  8. 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.
  9. 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
  10. 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.
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