20 Ophiuchi

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20 Ophiuchi
Ophiuchus constellation map.svg
Red circle.svg

Location of 20 Ophiuchi (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Ophiuchus
Right ascension 16h 49m 50.01604s[1]
Declination −10° 46′ 58.7775″[1]
Apparent magnitude (V) 4.64[2]
Spectral type F6IV[3]
U−B color index +0.07[4]
B−V color index +0.47[4]
Radial velocity (Rv) -1.60[5] km/s
Proper motion (μ) RA: +72.33[1] mas/yr
Dec.: -78.80[1] mas/yr
Parallax (π) 31.27 ± 2.16[1] mas
Distance 104 ± 7 ly
(32 ± 2 pc)
Absolute magnitude (MV) 2.13[2]
Mass 1.70[6] M
Radius 3.0[6] R
Luminosity 12.06[2] L
Surface gravity (log g) 3.89[7] cgs
Temperature 6,417[7] K
Metallicity [Fe/H] +0.13[7] dex
Rotational velocity (v sin i) 11.3[8] km/s
Other designations
BD-10°4394, FK5 1438, GC 22643, HIP 82369, HR 6243, HD 151769, SAO 160118
Database references

20 Ophiuchi is a class F6IV[3] (yellow-white subgiant) star in the constellation Ophiuchus. Its apparent magnitude is 4.64[2] and it is approximately 104 light years away based on parallax.[1] It lies near the star Zeta Ophiuchi.


  1. ^ a b c d e f Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. arXiv:0708.1752Freely accessible. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.  Vizier catalog entry
  2. ^ a b c d Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971Freely accessible. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015.  Vizier catalog entry
  3. ^ a b Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Bubar, E. J.; McGahee, C. E.; O'Donoghue, A. A.; Knox, E. R. (2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc--The Southern Sample". The Astronomical Journal. 132: 161. arXiv:astro-ph/0603770Freely accessible. Bibcode:2006AJ....132..161G. doi:10.1086/504637. 
  4. ^ a b Mallama, A. (2014). "Sloan Magnitudes for the Brightest Stars". The Journal of the American Association of Variable Star Observers. 42: 443. Bibcode:2014JAVSO..42..443M. Vizier catalog entry
  5. ^ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. 
  6. ^ a b 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. arXiv:astro-ph/9911002Freely accessible. Bibcode:1999A&A...352..555A.  Vizier catalog entry
  7. ^ a b c Wu, Yue; Singh, H. P.; Prugniel, P.; Gupta, R.; Koleva, M. (2010). "Coudé-feed stellar spectral library – atmospheric parameters". Astronomy & Astrophysics. 525: A71. arXiv:1009.1491Freely accessible. Bibcode:2011A&A...525A..71W. doi:10.1051/0004-6361/201015014. 
  8. ^ De Medeiros, J. R.; Mayor, M. (1999). "A catalog of rotational and radial velocities for evolved stars". Astronomy and Astrophysics Supplement Series. 139 (3): 433. Bibcode:1999A&AS..139..433D. doi:10.1051/aas:1999401.  Vizier catalog entry