Astronomy:20 Ophiuchi
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Short description: Star in the constellation Ophiuchus
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Ophiuchus |
| Right ascension | 16h 49m 50.01604s[1] |
| Declination | −10° 46′ 58.7775″[1] |
| Apparent magnitude (V) | 4.64[2] |
| Characteristics | |
| Spectral type | F6IV[3] |
| U−B color index | +0.07[4] |
| B−V color index | +0.47[4] |
| Astrometry | |
| 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] |
| Orbit[6] | |
| Period (P) | 35.5 ± 1.5 yr |
| Semi-major axis (a) | 0.460 ± 0.030″ |
| Eccentricity (e) | 0.8 ± 0.2 |
| Inclination (i) | 74 ± 11° |
| Longitude of the node (Ω) | 118 ± 9° |
| Periastron epoch (T) | 1981.2 ± 1.7 |
| Argument of periastron (ω) (secondary) | 34 ± 26° |
| Details | |
| 20 Oph A | |
| Mass | 1.70[7] M☉ |
| Radius | 3.0[7] R☉ |
| Luminosity | 12.06[2] L☉ |
| Surface gravity (log g) | 3.89[8] cgs |
| Temperature | 6,417[8] K |
| Metallicity [Fe/H] | +0.13[8] dex |
| Rotational velocity (v sin i) | 11.3[9] km/s |
| 20 Oph B | |
| Mass | 0.8 ± 0.2[6] M☉ |
| Other designations | |
BD-10°4394, FK5 1438, GC 22643, HIP 82369, HR 6243, HD 151769, SAO 160118 | |
| Database references | |
| SIMBAD | data |
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.
20 Ophiuchi is an astrometric binary. The primary star is a late F-type subgiant star. It has a mass 1.72 times that of the Sun.[6] The companion star regularly perturbs the primary star, causing it to wobble around the barycenter. From this, an orbital period of 35.5 years has been calculated. The secondary star is 0.8 times the mass of the Sun, and it may be a white dwarf or red dwarf.[6]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V. Vizier catalog entry
- ↑ 2.0 2.1 2.2 2.3 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A. Vizier catalog entry
- ↑ 3.0 3.1 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 (1): 161–170. doi:10.1086/504637. Bibcode: 2006AJ....132..161G.
- ↑ 4.0 4.1 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
- ↑ Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. Bibcode: 2006AstL...32..759G.
- ↑ 6.0 6.1 6.2 6.3 Gontcharov, G.A.; Kiyaeva, O.V. (2010). "Photocentric orbits from a direct combination of ground-based astrometry with Hipparcos II. Preliminary orbits for six astrometric binaries". New Astronomy 15 (3): 324–331. doi:10.1016/j.newast.2009.09.006. Bibcode: 2010NewA...15..324G.
- ↑ 7.0 7.1 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. Bibcode: 1999A&A...352..555A. Vizier catalog entry
- ↑ 8.0 8.1 8.2 Wu, Yue; Singh, H. P.; Prugniel, P.; Gupta, R.; Koleva, M. (2010). "Coudé-feed stellar spectral library – atmospheric parameters". Astronomy & Astrophysics 525: A71. doi:10.1051/0004-6361/201015014. Bibcode: 2011A&A...525A..71W.
- ↑ 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. doi:10.1051/aas:1999401. Bibcode: 1999A&AS..139..433D. Vizier catalog entry
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