HD 160529
HD 160529 (V905 Scorpii) is a luminous blue variable (LBV) star located in the constellation of Scorpius. With an apparent magnitude of around +6.8 cannot be seen with the naked eye except under very favourable conditions, but it's easy to see with binoculars or amateur telescopes.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Scorpius |
| Right ascension | 17h 41m 59.025s[1] |
| Declination | −33° 30′ 13.71″[1] |
| Apparent magnitude (V) | 6.66[2] (6.3 - 6.9[3]) |
| Characteristics | |
| Spectral type | LBV |
| U−B color index | +0.30[2] |
| B−V color index | +1.21[2] |
| Variable type | LBV[3] |
| Astrometry | |
| Radial velocity (Rv) | -35[4] km/s |
| Proper motion (μ) | RA: −1.75[1] mas/yr Dec.: −1.49[1] mas/yr |
| Parallax (π) | 0.54 ± 0.54[1] mas |
| Distance | 2,500[5] pc |
| Absolute magnitude (MV) | -8.9[6] |
| Details | |
| Mass | 13[6] M☉ |
| Radius | 150-330[3] R☉ |
| Luminosity | 290,000[5] L☉ |
| Surface gravity (log g) | 0.55[6] cgs |
| Temperature | 8,000-12,000[3] K |
| Rotational velocity (v sin i) | 45[3] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Physical characteristics
V905 Sco has a peculiar variable spectral type with emission lines and P Cygni profiles. At visual maximum it is similar to an A9 star and at minimum close to B8.[3] The distance has been estimated at 2.5 kiloparsecs (8,200 light years) based on the assumption of an absolute magnitude of -8.9.[6] However this distance is uncertain and values between 1.9 kiloparsecs and 3.5 kiloparsecs have been proposed.[3]
Working with a distance of 2.5 kiloparsecs, the radius varies from 150 R☉ when quiescent to 330 R☉ in outburst. The temperature also varies, from 8,000K in outburst to 12,000K when quiescent. With these parameters, the apparent visual magnitude varies by 0.5 and the bolometric luminosity is constant at 180,000 L☉.[3]
Estimates of the surface gravity lead to a mass of 13 M☉ and a probable initial mass of 25 M☉ This suggests that V905 Sco is a former red supergiant star.[6]
References
- Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357.
- Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237: 0. Bibcode:2002yCat.2237....0D.
- Stahl, O.; Gäng, T.; Sterken, C.; Kaufer, A.; Rivinius, T.; Szeifert, T.; Wolf, B. (March 2003). "Long-term spectroscopic monitoring of the Luminous Blue Variable HD 160529". Astronomy and Astrophysics. 400: 279–291. arXiv:astro-ph/0212473. Bibcode:2003A&A...400..279S. doi:10.1051/0004-6361:20021908.
- Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065.
- Nazé, Y.; Rauw, G.; Hutsemékers, D. (2012). "The first X-ray survey of Galactic luminous blue variables". Astronomy & Astrophysics. 538: A47. arXiv:1111.6375. Bibcode:2012A&A...538A..47N. doi:10.1051/0004-6361/201118040.
- Sterken, C.; Gosset, E.; Juttner, A.; Stahl, O.; Wolf, B.; Axer, M. (July 1991). "HD 160529 - a New Galactic Luminous Blue Variable". Astronomy and Astrophysics. 247 (2): 383. Bibcode:1991A&A...247..383S.