Omicron Boötis (ο Boötis) is a yellow-hued star in the northern constellation of Boötes. With an apparent visual magnitude of +4.60,[2] it is a fifth magnitude star that is visible to the naked eye. Based upon an annual parallax shift of 13.42 mas as seen from the Earth,[1] it is located about 243 light years from the Sun. The star is moving closer to the Sun with a radial velocity of −9 km/s.[6]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Boötes |
| Right ascension | 14h 45m 14.46026s[1] |
| Declination | +16° 57′ 51.4078″[1] |
| Apparent magnitude (V) | +4.60[2] |
| Characteristics | |
| Spectral type | G8.5 III[3] |
| U−B color index | +0.75[2] |
| B−V color index | +0.98[2] |
| Astrometry | |
| Radial velocity (Rv) | −9.18[4] km/s |
| Proper motion (μ) | RA: −60.69[1] mas/yr Dec.: −50.56[1] mas/yr |
| Parallax (π) | 13.42 ± 0.24 mas[1] |
| Distance | 243 ± 4 ly (75 ± 1 pc) |
| Absolute magnitude (MV) | 0.70[5] |
| Details | |
| Mass | 2.05[4] M☉ |
| Radius | 11[6] R☉ |
| Luminosity | 85[4] L☉ |
| Surface gravity (log g) | 2.7[6] cgs |
| Temperature | 4,864±25[4] K |
| Metallicity [Fe/H] | −0.10[6] dex |
| Rotational velocity (v sin i) | 3.6[6] km/s |
| Age | 2.72[4] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
At the age of 2.72 billion years,[4] this is an evolved G-type giant star with a stellar classification of G8.5 III.[3] It belongs to the so-called "red clump", which indicates it is generating energy through helium fusion at its core.[8] Although it displays a higher abundance of barium than is normal for a star of its type, Williams (1975) considers its status as a Barium star to be "very doubtful".[9] The star has double[4] the mass of the Sun and has expanded to 11[6] times the Sun's radius. It is radiating 85 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,864 K.[4]
References
edit- ^ a b c d e f 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.
- ^ a b c d Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99): 99, Bibcode:1966CoLPL...4...99J.
- ^ a b Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
- ^ a b c d e f g h Luck, R. Earle (September 2015), "Abundances in the Local Region. I. G and K Giants", The Astronomical Journal, 150 (3): 23, arXiv:1507.01466, Bibcode:2015AJ....150...88L, doi:10.1088/0004-6256/150/3/88, S2CID 118505114, 88.
- ^ McWilliam, Andrew (December 1990), "High-resolution spectroscopic survey of 671 GK giants. I - Stellar atmosphere parameters and abundances", Astrophysical Journal Supplement Series, 74: 1075–1128, Bibcode:1990ApJS...74.1075M, doi:10.1086/191527.
- ^ a b c d e f Massarotti, Alessandro; et al. (January 2008), "Rotational and radial velocities for a sample of 761 HIPPARCOS giants and the role of binarity", The Astronomical Journal, 135 (1): 209–231, Bibcode:2008AJ....135..209M, doi:10.1088/0004-6256/135/1/209, S2CID 121883397.
- ^ "omi Boo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-09-09.
- ^ 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.
- ^ Williams, P. M. (February 1975), "Stellar compositions from narrow-band photometry - V. Barium abundances for 200 evolved stars", Monthly Notices of the Royal Astronomical Society, 170 (2): 343–362, Bibcode:1975MNRAS.170..343W, doi:10.1093/mnras/170.2.343.