Astronomy:2 Scorpii
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Scorpius |
| Right ascension | 15h 53m 36.71880s[1] |
| Declination | −25° 19′ 37.7087″[1] |
| Apparent magnitude (V) | 4.69 + 6.98[2] |
| Characteristics | |
| Spectral type | B2.5 Vn[3] |
| B−V color index | −0.11/+0.07[2] |
| Astrometry | |
| Radial velocity (Rv) | −9.3±1.6[4] km/s |
| Proper motion (μ) | RA: −15.12[1] mas/yr Dec.: −25.18[1] mas/yr |
| Parallax (π) | 6.49 ± 0.51[1] mas |
| Distance | 500 ± 40 ly (150 ± 10 pc) |
| Absolute magnitude (MV) | −1.33[5] |
| Details | |
| 2 Sco A | |
| Mass | 6.9±0.1[6] M☉ |
| Luminosity | 457.40[5] L☉ |
| Temperature | 20,350[7] K |
| Rotational velocity (v sin i) | 320[8] km/s |
| Age | 30.4±4.6[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
2 Scorpii (A Scorpii) is a double star in the southern zodiac constellation of Scorpius. The brighter component has an apparent visual magnitude of 4.69, which is bright enough to be visible to the naked eye, while the fainter star is of magnitude 6.98.[2] The distance to this pair can be estimated from the annual parallax shift of 6.49±0.51 mas,[1] which places it roughly 500 light years away. It has a peculiar velocity of 16.5±2.4 km/s and is moving closer to the Sun with a heliocentric radial velocity of about −9 km/s,[4] which will bring it to a perihelion distance of 450 ly (139 pc) in about 2.9 million years.[5] This is a probable (73% chance) member of the Lower Centaurus–Crux group of the nearby Scorpius–Centaurus association (Sco OB2), or else (27% chance) it is a member of the Gould's Belt.[10]
With high likelihood (>95%), this is a binary star system. As of 2014, the pair had an angular separation of 2.061″±0.001″ along a position angle of 268.28°±0.02°.[7] The brighter member, component A, is a B-type main-sequence star with a stellar classification of B2.5 Vn.[3] The 'n' suffix indicates broad (nebulous) absorption lines due to rapid rotation. It is spinning with a projected rotational velocity of 320 km/s, giving the star an oblate shape with an equatorial bulge that is 15% larger than the polar radius.[8] Roughly 30[6] million years old, it has an estimated 6.9[6] times the mass of the Sun and is radiating 457[5] times the Sun's luminosity from its photosphere at an effective temperature of 20,350 K.[7]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 Fabricius, C. et al. (2002), "The Tycho double star catalogue", Astronomy and Astrophysics 384: 180–189, doi:10.1051/0004-6361:20011822, Bibcode: 2002A&A...384..180F.
- ↑ 3.0 3.1 Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode: 1988mcts.book.....H.
- ↑ 4.0 4.1 Bobylev, V. V.; Bajkova, A. T. (August 2013), "Galactic kinematics from a sample of young massive stars", Astronomy Letters 39 (8): 532–549, doi:10.1134/S106377371308001X, Bibcode: 2013AstL...39..532B.
- ↑ 5.0 5.1 5.2 5.3 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 6.0 6.1 6.2 6.3 Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society 410 (1): 190–200, doi:10.1111/j.1365-2966.2010.17434.x, Bibcode: 2011MNRAS.410..190T.
- ↑ 7.0 7.1 7.2
- ↑ 8.0 8.1 Belle, G. T. (2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review 20 (1): 51, doi:10.1007/s00159-012-0051-2, Bibcode: 2012A&ARv..20...51V.
- ↑ "2 Sco". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=2+Sco.
- ↑ Bobylev, V. V.; Bajkova, A. T. (September 2007), "Kinematics of the Scorpius–Centaurus OB association", Astronomy Letters 33 (9): 571–583, doi:10.1134/S1063773707090010, Bibcode: 2007AstL...33..571B.
External links
 |  |
