Omega2 Scorpii
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Scorpius |
| Right ascension | 16h 07m 24.32818s[1] |
| Declination | −20° 52′ 07.5518″[1] |
| Apparent magnitude (V) | +4.320[2] |
| Characteristics | |
| Evolutionary stage | horizontal branch[3] |
| Spectral type | G6/8III[4] |
| U−B color index | +0.494[2] |
| B−V color index | +0.850[2] |
| Astrometry | |
| Radial velocity (Rv) | −5.4[5] km/s |
| Proper motion (μ) | RA: +44.81[1] mas/yr Dec.: −45.42[1] mas/yr |
| Parallax (π) | 11.22 ± 0.32 mas[1] |
| Distance | 291 ± 8 ly (89 ± 3 pc) |
| Absolute magnitude (MV) | −0.62[6] |
| Details | |
| Mass | 3.27[6] M☉ |
| Radius | 15.0[7] R☉ |
| Luminosity | 163[7] L☉ |
| Surface gravity (log g) | 2.62±0.11[8] cgs |
| Temperature | 5,363±42[8] K |
| Metallicity [Fe/H] | +0.03±0.05[8] dex |
| Age | 282[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
ω2 Scorpii, Latinised as Omega2 Scorpii, is a suspected[11] variable star in the zodiac constellation of Scorpius. A component of the visual double star ω Scorpii, it is bright enough to be seen with the naked eye having an apparent visual magnitude of +4.320.[2] The distance to this star, as determined using parallax measurements,[1] is around 291 light years. The visual magnitude of this star is reduced by 0.38 because of extinction from interstellar dust.[6]
It is 0.05 degree north of the ecliptic, so can be occulted by the moon and planets.
This is a G-type giant star with a stellar classification of G6/8III.[4] With an estimated age of 282 million years,[6] it is an evolved, thin disk star that is currently on the red horizontal branch.[3] The interferometry-measured angular diameter of this star is 1.63 ± 0.10 mas,[12] which, at its estimated distance, equates to a physical radius of nearly 16 times the radius of the Sun.[13] It has 3.27 times the mass of the Sun,[6] and radiates 141 times the Sun's luminosity[14] The effective temperature of the star's outer atmosphere is 5,363 K.[8]
Names
[edit]In the Cook Islands, a traditional story is told of twins who flee their parents into the sky and become the pair of stars Omega2 and Omega1 Scorpii. The girl, who is called Piri-ere-ua "Inseparable", keeps tight hold of her brother, who is not named.[15] (The IAU used a version of this story from Tahiti to name Mu2 Scorpii.)
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 Kozok, J. R. (September 1985), "Photometric observations of emission B-stars in the southern Milky Way", Astronomy and Astrophysics Supplement Series, 61: 387–405, Bibcode:1985A&AS...61..387K.
- ^ a b Afşar, M.; et al. (July 2012), "Chemical Compositions of Thin-disk, High-metallicity Red Horizontal-branch Field Stars", The Astronomical Journal, 144 (1): 20, arXiv:1205.3659, Bibcode:2012AJ....144...20A, doi:10.1088/0004-6256/144/1/20, S2CID 119249237, 20.
- ^ a b Houk, N.; Smith-Moore, M. (1988), Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Declinations -26°.0 to -12°.0, vol. 4, Bibcode:1988mcts.book.....H.
- ^ Wilson, R. E. (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication, Carnegie Institute of Washington D.C., Bibcode:1953GCRV..C......0W.
- ^ a b c d e f Takeda, Yoichi; et al. (August 2008), "Stellar Parameters and Elemental Abundances of Late-G Giants", Publications of the Astronomical Society of Japan, 60 (4): 781–802, arXiv:0805.2434, Bibcode:2008PASJ...60..781T, doi:10.1093/pasj/60.4.781, S2CID 16258166.
- ^ a b Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c d Prugniel, P.; et al. (2011), "The atmospheric parameters and spectral interpolator for the MILES stars", Astronomy & Astrophysics, 531: A165, arXiv:1104.4952, Bibcode:2011A&A...531A.165P, doi:10.1051/0004-6361/201116769, S2CID 54940439.
- ^ Allen, Richard Hinckley (1963) [1899], Star Names: Their Lore and Meaning (Revised ed.), New York: Dover Publications, p. 367, ISBN 0-486-21079-0.
- ^ "* ome02 Sco". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2016-09-25.
- ^ Sterken, C. (January 1977), "uvby Photometry of the Suspected Variable omega2 Sco", Information Bulletin on Variable Stars, 1230: 1, Bibcode:1977IBVS.1230....1S.
- ^ Richichi, A.; Percheron, I. (May 2002), "CHARM: A Catalog of High Angular Resolution Measurements", Astronomy and Astrophysics, 386 (2): 492–503, Bibcode:2002A&A...386..492R, CiteSeerX 10.1.1.170.2863, doi:10.1051/0004-6361:20020236.
- ^ Lang, Kenneth R. (2006), Astrophysical formulae, Astronomy and astrophysics library, vol. 1 (3 ed.), Birkhäuser, ISBN 3-540-29692-1.. The radius (R*) is given by:
- ^ McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x, S2CID 118665352.
- ^ Johannes Carl Andersen (1931) Myths and Legends of the Polynesians. 1995 Dover reprint, p.399–400.
External links
[edit]- Kaler, James B. (September 9, 2016), "Omega-1 and Omega-2 Scorpii", Stars, University of Illinois, retrieved 2016-09-26.
