WR 69
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Triangulum Australe[1] |
| Right ascension | 15h 24m 11.31132s[2] |
| Declination | −62° 40′ 37.5784″[2] |
| Apparent magnitude (V) | 9.1[3] |
| Characteristics | |
| Evolutionary stage | Wolf-Rayet[4] |
| Spectral type | WC9d[5] |
| U−B color index | 0.05[3] |
| B−V color index | 0.414[3] |
| Astrometry | |
| Radial velocity (Rv) | 0.00[6] km/s |
| Proper motion (μ) | RA: −4.683[2] mas/yr Dec.: −4.519[2] mas/yr |
| Parallax (π) | 0.3625±0.0205 mas[2] |
| Distance | 9,000 ± 500 ly (2,800 ± 200 pc) |
| Absolute magnitude (MV) | −5.51[5] |
| Details | |
| Mass | 12.1[5] M☉ |
| Radius | 9.77[5] R☉ |
| Luminosity | 214,000[5] L☉ |
| Temperature | 40,000[5] K |
| Other designations | |
| WR 69, HD 136488, HIP 75377, 2MASS J15241131-6240374 | |
| Database references | |
| SIMBAD | data |
WR 69 is a Wolf–Rayet star located about 9,000 light years away in the constellation of Triangulum Australe. It is classified as a WC9 star, belonging to the late-type carbon sequence. WR 69 is also a prolific dust producer, hence the "d" in its spectral type.[5]
Binarity
WR 69 has generally been considered to be a binary (WC9d + O) star, with a period of 2.293 days and an amplitude of 0.044 magnitudes, suggesting it could be a short period colliding-wind binary. However, this periodicity is not due binary motion, but due to the fast rotation of the WC9d star, which rotates once every 2.15 days, at 40% of its breakup velocity. The WC9d star is likely part of a much longer binary system, hence the absorption lines found in its spectrum.[7]
Properties
WR 69 is quite average for a WC9 star. Modelling WR 69's spectrum gives a temperature of 40,000 K, and a luminosity of ~214,000 L☉ is derived from the Gaia DR2 parallax. From this a radius can be derived using the Stefan-Boltzmann Law, which turns out at just under 10 R☉.[5] However, in the visual wavelength, the star is just 13,600 L☉ bright,[5] because most of the 214,000 L☉ is emitted in the ultraviolet wavelength. WR 69 has 12.1 solar masses,[5] but it likely started its life with much more than this, and lost much of it through its powerful stellar wind.
WR 69 has a very strong stellar wind, typical of Wolf-Rayet stars. WR 69 loses 10−4.87 M☉ (about 1.35×10−5 M☉) per year because of this stellar wind, which has a terminal velocity of 1,089 kilometres per second.[5]
References
- ^ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
- ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". VizieR Online Data Catalog. 2237. Bibcode:2002yCat.2237....0D.
- ^ Crowther, Paul A.; Rate, Gemma (2020). "Unlocking Galactic Wolf–Rayet stars with Gaia DR2 – I. Distances and absolute magnitudes". Monthly Notices of the Royal Astronomical Society. 493 (1): 1512–1529. arXiv:1912.10125. Bibcode:2020MNRAS.493.1512R. doi:10.1093/mnras/stz3614. S2CID 209444955.
- ^ a b c d e f g h i j k Sander, A. A. C.; Hamann, W.-R.; Todt, H.; Hainich, R.; Shenar, T.; Ramachandran, V.; Oskinova, L. M. (2019-01-01). "The Galactic WC and WO stars. The impact of revised distances from Gaia DR2 and their role as massive black hole progenitors". Astronomy and Astrophysics. 621: A92. arXiv:1807.04293. Bibcode:2019A&A...621A..92S. doi:10.1051/0004-6361/201833712. ISSN 0004-6361. S2CID 67754788.
- ^ Kharchenko, N. V.; Scholz, R.-D.; Piskunov, A. E.; Röser, S.; Schilbach, E. (2007-11-01). "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ~55000 stars and mean radial velocities of 516 Galactic open clusters and associations". Astronomische Nachrichten. 328 (9): 889–896. arXiv:0705.0878. Bibcode:2007AN....328..889K. doi:10.1002/asna.200710776. ISSN 0004-6337. S2CID 119323941.
- ^ Fahed, R.; Moffat, A. F. J. (2012-08-01). "Colliding winds in five WR+O systems of the Southern hemisphere". Monthly Notices of the Royal Astronomical Society. 424 (3): 1601–1613. Bibcode:2012MNRAS.424.1601F. doi:10.1111/j.1365-2966.2012.20494.x. ISSN 0035-8711.
