WR 93b
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Scorpius |
| Right ascension | 17h 32m 03.31s[1] |
| Declination | −35° 04′ 32.4″[1] |
| Characteristics | |
| Evolutionary stage | Wolf-Rayet star |
| Spectral type | WO3[2] |
| Apparent magnitude (B) | 16.9[1] |
| Apparent magnitude (R) | 14.4[1] |
| Apparent magnitude (J) | 11.331[1] |
| Apparent magnitude (K) | 10.17[3] |
| Astrometry | |
| Proper motion (μ) | RA: −0.579±0.096[4] mas/yr Dec.: −2.171±0.075[4] mas/yr |
| Parallax (π) | 0.3735 ± 0.0658 mas[4] |
| Distance | 2,300±300[5] pc |
| Details | |
| Mass | 7.1+2.4 −1.8[5] M☉ |
| Radius | 0.39+0.11 −0.09[5] R☉ |
| Luminosity | 91,200+60,200 −36,200[5] L☉ |
| Temperature | 160,000[2] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
WR 93b is a Wolf-Rayet star in the constellation Scorpius, an extremely rare star on the WO oxygen sequence.
Discovery
WR 93b was discovered in 2003 during a study of emission line stars from the AAO/UKST Southern Galactic Plane Hα Survey. It was published as the fourth galactic WO class star in 1994.[6] This was too late to be included in the VIIth Wolf Rayet catalogue,[7] but it is listed in an annex published in 2006.[3]
It lies in the direction of the galactic centre and is thought to be part of the Scutum-Crux spiral arm. It is highly reddened and Interstellar extinction causes it to be 6.5 magnitudes fainter at visual wavelengths.[6]
Features
WR 93b, of spectral classification WO3, is one of the very few known oxygen-sequence Wolf-Rayet stars, just four in the Milky Way galaxy and five in external galaxies. Modelling the atmosphere gives a luminosity around 200,000 L☉. It is a very small dense star, with a radius less than the sun's but with a mass nearly 10 solar masses. Very strong stellar winds, with a terminal velocity of 5,000 kilometers per second are causing WR 93b to lose 10−5 M☉/year.[2] For comparison, the Sun loses (2-3) x 10−14 solar masses per year due to its solar wind, several hundred million times less than WR 93b.
Evolutionary status
WO Wolf-Rayet stars are the last evolutionary stage of the most massive stars before exploding as supernovae, possibly with a gamma-ray burst.[8] It is very likely that WR 93b is on its last stages of nuclear fusion, near or beyond the end of helium burning.[9] It has been calculated that WR 93b will explode as a supernova within 8,000 years.[2]
See also
References
- ^ a b c d e Cutri, R. M.; Skrutskie, M. F.; Van Dyk, S.; Beichman, C. A.; Carpenter, J. M.; Chester, T.; Cambresy, L.; Evans, T.; Fowler, J.; Gizis, J.; Howard, E.; Huchra, J.; Jarrett, T.; Kopan, E. L.; Kirkpatrick, J. D.; Light, R. M.; Marsh, K. A.; McCallon, H.; Schneider, S.; Stiening, R.; Sykes, M.; Weinberg, M.; Wheaton, W. A.; Wheelock, S.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". VizieR On-line Data Catalog: II/246. Originally published in: 2003yCat.2246....0C. 2246. Bibcode:2003yCat.2246....0C.
- ^ a b c d Tramper, F.; Straal, S. M.; Sanyal, D.; Sana, H.; de Koter, A.; Gräfener, G.; Langer, N.; Vink, J. S.; de Mink, S. E.; Kaper, L. (2015). "Massive stars on the verge of exploding: The properties of oxygen sequence Wolf-Rayet stars". Astronomy & Astrophysics. 581 (110): A110. arXiv:1507.00839v1. Bibcode:2015A&A...581A.110T. doi:10.1051/0004-6361/201425390.
- ^ a b Van Der Hucht, K. A. (2006). "New Galactic Wolf-Rayet stars, and candidates. An annex to the VIIth Catalogue of Galactic Wolf-Rayet Stars". Astronomy and Astrophysics. 458 (2): 453–459. arXiv:astro-ph/0609008. Bibcode:2006A&A...458..453V. doi:10.1051/0004-6361:20065819.
- ^ a b c Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c d Stevance, H F; Ignace, R; Crowther, P A; Maund, J R; Davies, B; Rate, G (2018). "Probing the rotational velocity of Galactic WO stars with spectropolarimetry". Monthly Notices of the Royal Astronomical Society. 479 (4): 4535–4543. arXiv:1807.02117. Bibcode:2018MNRAS.tmp.1751S. doi:10.1093/mnras/sty1827.
{{cite journal}}: CS1 maint: bibcode (link) CS1 maint: unflagged free DOI (link) - ^ a b Drew, Janet E.; Barlow, M. J.; Unruh, Y. C.; Parker, Q. A.; Wesson, R.; Pierce, M. J.; Masheder, M. R. W.; Phillipps, S. (2004). "Discovery of a WO star in the Scutum-Crux arm of the inner Galaxy" (Submitted manuscript). Monthly Notices of the Royal Astronomical Society. 351: 206–214. arXiv:astro-ph/0403482. Bibcode:2004MNRAS.351..206D. doi:10.1111/j.1365-2966.2004.07771.x.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ van der Hucht, Karel A. (2001). "The VIIth catalogue of galactic Wolf–Rayet stars". New Astronomy Reviews. 45 (3): 135–232. Bibcode:2001NewAR..45..135V. doi:10.1016/S1387-6473(00)00112-3. ISSN 1387-6473.
- ^ Groh, Jose H.; Meynet, Georges; Georgy, Cyril; Ekstrom, Sylvia (2013). "Fundamental properties of core-collapse Supernova and GRB progenitors: Predicting the look of massive stars before death". Astronomy & Astrophysics. 558: A131. arXiv:1308.4681. Bibcode:2013A&A...558A.131G. doi:10.1051/0004-6361/201321906.
- ^ Groh, Jose (2014). "The evolution of massive stars and their spectra I. A non-rotating 60 Msun star from the zero-age main sequence to the pre-supernova stage". Astronomy & Astrophysics. 564: A30. arXiv:1401.7322. Bibcode:2014A&A...564A..30G. doi:10.1051/0004-6361/201322573.
