Omega1 Scorpii

For other stars with this Bayer designation, see ω Scorpii
ω1 Scorpii
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Scorpius
Right ascension 16h 06m 48.42692s[1]
Declination −20° 40′ 09.0902″[1]
Apparent magnitude (V) +3.95[2]
Characteristics
Spectral type B1 V[2]
U−B color index −0.82
B−V color index −0.05[3]
Variable type Beta Cephei variable[4]
Astrometry
Radial velocity (Rv)−3.1[5] km/s
Proper motion (μ) RA: −8.98[1] mas/yr
Dec.: −23.48[1] mas/yr
Parallax (π)6.92 ± 0.26[1] mas
Distance470 ± 20 ly
(145 ± 5 pc)
Details
Mass11.4[6] M☉
Radius6.6[7] R☉
Luminosity9,120[6] L☉
Temperature26,530[2] K
Metallicity [Fe/H]−0.45±0.15[8] dex
Rotation14.4 h[4]
Rotational velocity (v sin i)105[4] km/s
Age5[6] Myr
Other designations
Jabhat al Akrab, ω1 Sco, 9 Scorpii, HD 144470, HIP 78933, HR 5993, SAO 184123.[9]

Omega1 Scorpii is a star in the zodiac constellation of Scorpius. With an apparent visual magnitude of 3.95,[2] it can be seen with the naked eye. Parallax measurements of this star give an estimated distance of around 470 light years from the Sun. It is a member of the Scorpius–Centaurus Association.[10]

This is a B-type main sequence star with a stellar classification of B1 V.[2] It has a luminosity of 9,120 Suns, consistent with an isochronal age of 5 million years and an estimated mass of 11 solar masses.[6] The radius is about 6.6 times that of the Sun.[7] It has an effective temperature of 26,530 in its outer atmosphere.[2]

Omega1 Scorpii is a β Cephei star that undergoes non-radial pulsations at a rate of 15 cycles per day.[8] This is causing the surface temperature to fluctuate between 28,300 K and 22,600 K along the equator. The star is spinning rapidly with a projected rotational velocity of 105 km/s and an estimated rotation period of 14h.4. The poles of the star are inclined by around 60° to the line-of-sight from the Earth.[4]

References

  1. 1 2 3 4 5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357.
  2. 1 2 3 4 5 6 Bragança, G. A.; et al. (November 2012), "Projected Rotational Velocities and Stellar Characterization of 350 B Stars in the Nearby Galactic Disk", The Astronomical Journal, 144 (5): 10, Bibcode:2012AJ....144..130B, doi:10.1088/0004-6256/144/5/130, 130.
  3. ↑ Deutschman, W. A.; et al. (February 1976), "The galactic distribution of interstellar absorption as determined from the Celescope catalog of ultraviolet stellar observations and a new catalog of UBV, H-beta photoelectric observations", Astrophysical Journal Supplement Series, 30: 97−225, Bibcode:1976ApJS...30...97D, doi:10.1086/190359.
  4. 1 2 3 4 Berdyugina, S. V.; et al. (July 2003), "Surface imaging of stellar non-radial pulsations. II. The β Cephei star ω1 Sco", Astronomy and Astrophysics, 406: 281−285, Bibcode:2003A&A...406..281B, doi:10.1051/0004-6361:20030747.
  5. ↑ Evans, D. S. (June 20–24, 1966), Batten, Alan Henry; Heard, John Frederick, eds., "The Revision of the General Catalogue of Radial Velocities", Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, University of Toronto: International Astronomical Union, Bibcode:1967IAUS...30...57E.
  6. 1 2 3 4 Pecaut, Mark J.; et al. (February 2012), "A Revised Age for Upper Scorpius and the Star Formation History among the F-type Members of the Scorpius-Centaurus OB Association", Astrophysical Journal, 746 (2): 154, arXiv:1112.1695Freely accessible, Bibcode:2012ApJ...746..154P, doi:10.1088/0004-637X/746/2/154. See table 7.
  7. 1 2 Pasinetti Fracassini, L. E.; et al. (February 2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS) - Third edition - Comments and statistics", Astronomy and Astrophysics, 367 (2): 521–524, arXiv:astro-ph/0012289Freely accessible, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451.
  8. 1 2 Daszyńska-Daszkiewicz, J.; Niemczura, E. (April 2005), "Metallicity of mono- and multiperiodic β Cephei stars", Astronomy and Astrophysics, 433 (3): 1031−1035, Bibcode:2005A&A...433.1031D, doi:10.1051/0004-6361:20040397.
  9. ↑ "ome Sco -- Variable Star of beta Cep type", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2016-09-25.
  10. ↑ Jilinski, E.; et al. (March 2006), "Radial velocity measurements of B stars in the Scorpius-Centaurus association", Astronomy and Astrophysics, 448 (3): 1001–1006, arXiv:astro-ph/0601643Freely accessible, Bibcode:2006A&A...448.1001J, doi:10.1051/0004-6361:20041614.
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