Upsilon2 Centauri
Upsilon2 Centauri (υ2 Centauri) is a binary star[6] system in the southern constellation Centaurus. It is visible to the naked eye with an apparent visual magnitude of +4.33.[2] Based upon an annual parallax shift of just 2.57 mas as seen from Earth,[1] this star is located roughly 1,300 light years from the Sun. Relative to its neighbors, the system has a peculiar velocity of 39.2+8.8
−15.2 km/s and it may form a runaway star system.[9]
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Centaurus |
| Right ascension | 14h 01m 43.49909 s[1] |
| Declination | −45° 36′ 12.2767″[1] |
| Apparent magnitude (V) | +4.33[2] |
| Characteristics | |
| Spectral type | F7 II/III[3] |
| U−B color index | +0.26[2] |
| B−V color index | +0.61[2] |
| Variable type | None[4] |
| Astrometry | |
| Radial velocity (Rv) | −7.8±7.4[5] km/s |
| Proper motion (μ) | RA: +8.64±1.09[1] mas/yr Dec.: −16.25±0.88[1] mas/yr |
| Parallax (π) | 2.57 ± 1.05 mas[1] |
| Distance | approx. 1,300 ly (approx. 400 pc) |
| Absolute magnitude (MV) | −3.51[4] |
| Orbit[6] | |
| Period (P) | 207.357 d |
| Eccentricity (e) | 0.55 |
| Periastron epoch (T) | 2423880.5 JD |
| Argument of periastron (ω) (secondary) | 88° |
| Semi-amplitude (K1) (primary) | 12.7 km/s |
| Details | |
| Mass | 6.86±0.39[7] M☉ |
| Luminosity (bolometric) | 3,919[7] L☉ |
| Surface gravity (log g) | 2.00[8] cgs |
| Temperature | 6,495[7] K |
| Rotational velocity (v sin i) | 0.0[8] km/s |
| Age | 45.9±4.0[9] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is a single-lined spectroscopic binary star system with an orbital period of 207.357 days and an eccentricity of 0.55.[6] The primary component has the spectrum of an evolved F-type giant/bright giant hybrid with a stellar classification of F7 II/III.[3] It is around 46[9] million years old with 6.9 times the mass of the Sun. The star is radiating 3,919 times the Sun's luminosity from its photosphere at an effective temperature of 6,495 K.[7]
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 Fernie, J. D. (1983), "New UBVRI photometry for 900 supergiants", Astrophysical Journal Supplement Series, 52: 7, Bibcode:1983ApJS...52....7F, doi:10.1086/190856.
- ^ a b Houk, N. (1987), "Michigan Catalogue of two dimensional spectral types for the HD stars", Michigan Spectral Survey, 2, Bibcode:1978mcts.book.....H.
- ^ a b Eggen, O. J. (July 1985), "Cepheids and nonvariable supergiants", Astronomical Journal, 90: 1260–1277, Bibcode:1985AJ.....90.1260E, doi:10.1086/113834.
- ^ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
- ^ a b c Pourbaix, D.; et al. (2004), "SB9: The Ninth Catalogue of Spectroscopic Binary Orbits", Astronomy & Astrophysics, 424: 727–732, arXiv:astro-ph/0406573, Bibcode:2004A&A...424..727P, doi:10.1051/0004-6361:20041213, S2CID 119387088.
- ^ a b c d Hohle, M. M.; et al. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten, 331 (4): 349, arXiv:1003.2335, Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355, S2CID 111387483.
- ^ a b Mallik, Sushma V.; et al. (October 2003), "Lithium and rotation in F and G dwarfs and subgiants", Astronomy and Astrophysics, 409: 251–261, Bibcode:2003A&A...409..251M, doi:10.1051/0004-6361:20031084.
- ^ a b c 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, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873.
- ^ "ups02 Cen". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-08-29.