Sigma Ophiuchi
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ophiuchus |
| Right ascension | 17h 26m 30.88004s[1] |
| Declination | 4° 08′ 25.2940″[1] |
| Apparent magnitude (V) | 4.31[2] (4.25 - 4.51[3]) |
| Characteristics | |
| Spectral type | K2III[4] |
| U−B color index | +1.57[2] |
| B−V color index | +1.51[2] |
| Variable type | suspected[3] |
| Astrometry | |
| Radial velocity (Rv) | -27.81[5] km/s |
| Proper motion (μ) | RA: +0.72[1] mas/yr Dec.: +7.03[1] mas/yr |
| Parallax (π) | 3.62 ± 0.29 mas[1] |
| Distance | 900 ± 70 ly (280 ± 20 pc) |
| Absolute magnitude (MV) | -2.85[6] |
| Details | |
| Mass | 4.87[7] M☉ |
| Radius | 73.25[7] R☉ |
| Luminosity | 2047[7] L☉ |
| Surface gravity (log g) | 1.52[8] cgs |
| Temperature | 4,540[7] K |
| Metallicity [Fe/H] | -0.07[7] dex |
| Rotational velocity (v sin i) | 4.2[9] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Sigma Ophiuchi (σ Oph) is a class K2III[4] (orange giant) star in the constellation Ophiuchus. Its apparent magnitude is 4.31[2] and it is approximately 900 light years away based on parallax.[1]
References
- ^ a b c d e f Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. Vizier catalog entry
- ^ a b c d Ducati, J. R. (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.
- ^ a b 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. Bibcode:2009yCat....102025S.
- ^ a b Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars, Vol. 5". Michigan Spectral Survey. 05: 0. Bibcode:1999MSS...C05....0H.
- ^ Famaey, B.; Jorissen, A.; Luri, X.; Mayor, M.; Udry, S.; Dejonghe, H.; Turon, C. (2005). "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data". Astronomy & Astrophysics. 430: 165. arXiv:astro-ph/0409579. Bibcode:2005A&A...430..165F. doi:10.1051/0004-6361:20041272.
- ^ 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. Vizier catalog entry
- ^ a b c d e Reffert, Sabine; Bergmann, Christoph; Quirrenbach, Andreas; Trifonov, Trifon; Künstler, Andreas (2015). "Precise radial velocities of giant stars". Astronomy & Astrophysics. 574: A116. arXiv:1412.4634. Bibcode:2015A&A...574A.116R. doi:10.1051/0004-6361/201322360. Vizier catalog entry
- ^ Hekker, S.; Meléndez, J. (2007). "Precise radial velocities of giant stars". Astronomy and Astrophysics. 475 (3): 1003. arXiv:0709.1145. Bibcode:2007A&A...475.1003H. doi:10.1051/0004-6361:20078233.
- ^ 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
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