Astronomy:WR 119
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Scutum |
| Right ascension | 18h 39m 17.904s[1] |
| Declination | −10° 50′ 30.90″[1] |
| Apparent magnitude (V) | 12.06[2] |
| Characteristics | |
| Evolutionary stage | Wolf-Rayet |
| Spectral type | WC9d[3] |
| B−V color index | +0.93[2] |
| Astrometry | |
| Proper motion (μ) | RA: −1.223[1] mas/yr Dec.: −5.285[1] mas/yr |
| Parallax (π) | 0.2098 ± 0.0155[1] mas |
| Distance | 3,220+1,240 −730[4] pc |
| Absolute magnitude (MV) | −3.91[3] |
| Details | |
| Mass | 5.8[3] M☉ |
| Radius | 3.7[3] R☉ |
| Luminosity | 50,100[3] L☉ |
| Temperature | 45,000[3] K |
| Other designations | |
WR 119, 2MASS J18391789-1005309 | |
| Database references | |
| SIMBAD | data |
WR 119 is a Wolf–Rayet star located about 10,500 light years away in the constellation Scutum. WR 119 is classified as a WC9 star, belonging to the late-type carbon sequence of Wolf-Rayet stars. WR 119 is noteworthy for being the least luminous known Wolf-Rayet star, at just over 50,000 L☉.[3] The most recent estimate is even lower, at just 42,700 L☉, based on the most recent analysis using Gaia DR2 data.[4]
Properties
WR 119's properties are on the very edge of what may be possible for Wolf-Rayet stars, due to being so extremely dim. Modelling its spectrum using PoWR gives a temperature of 45,000 K. Factoring in the distance used in that study of 3,500 pc, WR 119's luminosity is only 50,100 L☉, derived from Gaia DR2's parallax data. The corresponding radius is only 3.7 R☉, the smallest of the WC9 stars, less than half the size of the average WC9 star. WR 119's luminosity is also just 20% that of the average WC9 star's luminosity. The corresponding mass is just 5.8 M☉, the lowest mass for any Wolf-Rayet star derived using a mass-luminosity relation.[3]
In the visual wavelength, the star is also the dimmest of the WC9 stars (and anything later than WC4 in the study), with a visual luminosity of just 3,130 L☉[3] because most of the 50,100 L☉ is emitted at ultraviolet wavelengths due to WR 119's very high surface temperature.
WR 119 has a strong stellar wind, typical of Wolf-Rayet stars, but weaker than most WC stars. WR 119 loses 10-5.13 M☉ (about 7.41×10−6 M☉) per year because of this stellar wind, which has a terminal velocity of 1,300 kilometres per second. WR 119 also emits a lot of dust, hence the "d" at the end of its spectral type,[3] which may be an indication of binary status.
References
- ↑ 1.0 1.1 1.2 1.3 1.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 Jayasinghe, T; Kochanek, C S; Stanek, K Z; Shappee, B J; Holoien, T W-S; Thompson, Toda A; Prieto, J L; Dong, Subo et al. (1 July 2018). "The ASAS-SN catalogue of variable stars I: The Serendipitous Survey". Monthly Notices of the Royal Astronomical Society 477 (3): 3145–3163. doi:10.1093/mnras/sty838. ISSN 0035-8711. Bibcode: 2018MNRAS.477.3145J.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 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. doi:10.1051/0004-6361/201833712. ISSN 0004-6361. Bibcode: 2019A&A...621A..92S.
- ↑ 4.0 4.1 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. doi:10.1093/mnras/stz3614. Bibcode: 2020MNRAS.493.1512R.
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