Omicron Boötis

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]

Omicron Boötes
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[1] mas
Distance243 ± 4 ly
(75 ± 1 pc)
Absolute magnitude (MV)0.70[5]
Details
Mass2.05[4] M☉
Radius11[6] R☉
Luminosity85[4] L☉
Surface gravity (log g)2.7[6] cgs
Temperature4,864±25[4] K
Metallicity [Fe/H]−0.10[6] dex
Rotational velocity (v sin i)3.6[6] km/s
Age2.72[4] Gyr
Other designations
ο Boo, 35 Boötis, BD+17° 2780, GC 19858, GJ 9493, HD 129972, HIP 72125, HR 5502, SAO 101184[7]
Database references
SIMBADdata

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
  1. 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.
  2. 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.
  3. 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.
  4. 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.
  5. 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.
  6. 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.
  7. "omi Boo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-09-09.
  8. 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.
  9. 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.
  • Hoffleit; et al. (1991), "HR 5502", Bright Star Catalogue (5th Revised ed.), retrieved 2017-09-12.
  • "omi Boo", Aladin previewer, Centre de Données astronomiques de Strasbourg, retrieved 2017-09-12.
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