Omega1 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 mas[1] |
| Distance | 470 ± 20 ly (145 ± 5 pc) |
| Absolute magnitude (MV) | −1.87[6] |
| Details | |
| Mass | 11.4[7] M☉ |
| Radius | 6.6[8] R☉ |
| Luminosity | 9,120[7] L☉ |
| Temperature | 26,530[2] K |
| Metallicity [Fe/H] | −0.45±0.15[9] dex |
| Rotation | 14.4 h[4] |
| Rotational velocity (v sin i) | 105[4] km/s |
| Age | 5[7] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
ω1 Scorpii, Latinised as 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, 0.22 degree north of the ecliptic. 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.[11]
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.[7] The radius is about 6.6 times that of the Sun.[8] 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.[9] 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]
Names
In the Cook Islands, a traditional story is told of twins who flee their parents into the sky and become the pair of stars Omega1 and Omega2 Scorpii. The girl, who is called Piri-ere-ua "Inseparable", keeps tight hold of her brother, who is not named.[12] (The IAU used a version of this story from Tahiti to name Mu2 Scorpii.)
References
- ^ a b c d e 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.
- ^ a b c d e f 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, arXiv:1208.1674, Bibcode:2012AJ....144..130B, doi:10.1088/0004-6256/144/5/130, 130.
- ^ 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.
- ^ a b c d 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.
- ^ 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, vol. 30, University of Toronto: International Astronomical Union, p. 57, Bibcode:1967IAUS...30...57E.
- ^ 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.
- ^ a b c d 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:1112.1695, Bibcode:2012ApJ...746..154P, doi:10.1088/0004-637X/746/2/154. See table 7.
{{citation}}: CS1 maint: postscript (link) - ^ a b 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/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451.
- ^ a b Daszyńska-Daszkiewicz, J.; Niemczura, E. (April 2005), "Metallicity of mono- and multiperiodic β Cephei stars", Astronomy and Astrophysics, 433 (3): 1031–1035, arXiv:astro-ph/0410442, Bibcode:2005A&A...433.1031D, doi:10.1051/0004-6361:20040397.
- ^ "* ome01 Sco". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-09-25.
- ^ 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/0601643, Bibcode:2006A&A...448.1001J, doi:10.1051/0004-6361:20041614.
- ^ Johannes Carl Andersen (1931) Myths and Legends of the Polynesians. 1995 Dover reprint, p.399–400.
External links
- Kaler, James B. (September 9, 2016), "Omega-1 and Omega-2 Scorpii", Stars, University of Illinois, retrieved 2016-09-26.
