WR 93b

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WR 93b
Antares overlooking an Auxiliary Telescope.jpg
Red circle.svg
Location of WR 93b (circled in red). Scorpius runs across the top of the image from Antares at top left to the end of the tail on the right.
Observation data
Epoch J2000.0        Equinox J2000.0
Constellation Scorpius
Right ascension 17h 32m 03.308s [1]
Declination −35° 04′ 32.62″ [1]
Apparent magnitude  (V)15.2 [2]
Characteristics
Evolutionary stage Wolf-Rayet star
Spectral type WO3 [3]
Apparent magnitude  (B)16.9 [4]
Apparent magnitude  (R)14.4 [4]
Apparent magnitude  (J)11.331 [4]
Apparent magnitude  (K)10.17 [5]
Astrometry
Proper motion (μ)RA: −0.642±0.032 [1]   mas/yr
Dec.: −2.1055±0.024 [1]   mas/yr
Parallax (π)0.4298 ± 0.0288  mas [1]
Distance 7,600 ± 500  ly
(2,300 ± 200  pc)
Details
Mass 8.1+1.9
−1.2 [6]   M☉
Radius 0.44 [6]   R☉
Luminosity 110,000+53,000
−30,000 [6]   L☉
Temperature 160,000 [3]   K
Other designations
2MASS  J17320330-3504323, SSTGLMC  G353.2744-00.8460
Database references
SIMBAD data

WR 93b is a Wolf-Rayet star in the constellation Scorpius, an extremely rare star on the WO oxygen sequence. It appears near NGC 6357 in the tail of the scorpion.

Contents

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. [7] This was too late to be included in the VIIth Wolf Rayet catalogue, [8] but it is listed in an annex published in 2006. [5]

It lies in the direction of the Galactic Center 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 than it otherwise would be. [7]

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 six in external galaxies. Modelling the atmosphere gives a luminosity around 110,000 L☉, very low for a Wolf-Rayet star. [6] It is a very small dense star, with a radius less than half of 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. [3] 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. [9] It is very likely that WR 93b is on its last stages of nuclear fusion, near or beyond the end of helium burning. [10] It has been calculated that WR 93b will explode as a supernova within 8,000 years. [3]

See also

Related Research Articles

<span class="mw-page-title-main">Wolf–Rayet star</span> Heterogeneous stars with unusual spectra

Wolf–Rayet stars, often abbreviated as WR stars, are a rare heterogeneous set of stars with unusual spectra showing prominent broad emission lines of ionised helium and highly ionised nitrogen or carbon. The spectra indicate very high surface enhancement of heavy elements, depletion of hydrogen, and strong stellar winds. The surface temperatures of known Wolf–Rayet stars range from 20,000 K to around 210,000 K, hotter than almost all other kinds of stars. They were previously called W-type stars referring to their spectral classification.

<span class="mw-page-title-main">WR 136</span> Star in the constellation of Cygnus

WR 136 is a Wolf–Rayet star located in the constellation Cygnus. It is in the center of the Crescent Nebula. Its age is estimated to be around 4.7 million years and it is nearing the end of its life. Within a few hundred thousand years, it is expected to explode as a supernova.

<span class="mw-page-title-main">WR 104</span> Triple star system

WR 104 is a triple star system located about 2,580 parsecs (8,400 ly) from Earth. The primary star is a Wolf–Rayet star, which has a B0.5 main sequence star in close orbit and another more distant fainter companion.

<span class="mw-page-title-main">EZ Canis Majoris</span> Binary star system in the constellation Canis Major

EZ Canis Majoris is binary system in the constellation of Canis Major. The primary is a Wolf-Rayet star and it is one of the ten brightest Wolf-Rayet stars, brighter than apparent magnitude 7.

<span class="mw-page-title-main">WR 148</span> Binary star in the constellation of Cygnus

WR 148 is a spectroscopic binary in the constellation Cygnus. The primary star is a Wolf–Rayet star and one of the most luminous stars known. The secondary has been suspected of being a stellar-mass black hole but may be a class O main sequence star.

WR 156 is a young massive and luminous Wolf–Rayet star in the constellation of Cepheus. Although it shows a WR spectrum, it is thought to be a young star still fusing hydrogen in its core.

<span class="mw-page-title-main">WR 134</span> Star in the constellation of Cygnus

WR 134 is a variable Wolf-Rayet star located around 6,000 light years away from Earth in the constellation of Cygnus, surrounded by a faint bubble nebula blown by the intense radiation and fast wind from the star. It is five times the radius of the sun, but due to a temperature over 63,000 K it is 400,000 times as luminous as the Sun.

WR 142 is a Wolf-Rayet star in the constellation Cygnus, an extremely rare star on the WO oxygen sequence. It is a luminous and very hot star, highly evolved and close to exploding as a supernova. It is suspected to be a binary star with a companion orbiting about 1 AU away.

<span class="mw-page-title-main">WR 102</span> Star in the constellation Sagittarius

WR 102 is a Wolf–Rayet star in the constellation Sagittarius, an extremely rare star on the WO oxygen sequence. It is a luminous and very hot star, highly evolved and close to exploding as a supernova.

<span class="mw-page-title-main">WR 31a</span> Wolf Rayet star in the constellation Carina

WR 31a, commonly referred to as Hen 3-519, is a Wolf–Rayet (WR) star in the southern constellation of Carina that is surrounded by an expanding Wolf–Rayet nebula. It is not a classical old stripped-envelope WR star, but a young massive star which still has some hydrogen left in its atmosphere.

WR 114 is a Wolf-Rayet star in the constellation of Scutum. It is an early type star of the carbon sequence (WCE) classified as WC5.

<span class="mw-page-title-main">WR 30a</span> Binary star in the constellation Carina

WR 30a is a massive spectroscopic binary in the constellation Carina. The primary is an extremely rare star on the WO oxygen sequence and the secondary a massive class O star. It appears near the Carina Nebula but is much further away.

WR 111 is a Wolf-Rayet (WR) star in the constellation Sagittarius. It is magnitude 7.8 and lies about 5,150 light-years away. It is one of the brightest and most closely studied WR stars.

<span class="mw-page-title-main">WR 86</span>

WR 86 is a visual binary in the constellation Scorpius consisting of a Wolf-Rayet star and a β Cephei variable. It lies 2° west of NGC 6357 on the edge of the Great Rift in the Milky Way in the tail of the Scorpion.

<span class="mw-page-title-main">WR 1</span> Star in the constellation Cassiopeia

WR 1 is a Wolf-Rayet star located around 10,300 light years away from Earth in the constellation of Cassiopeia. It is only slightly more than twice the size of the sun, but due to a temperature over 100,000 K it is over 758,000 times as luminous as the sun.

WR 2 is a Wolf-Rayet star located around 8,000 light years away from Earth in the constellation of Cassiopeia, in the stellar association Cassiopeia OB1. It is smaller than the Sun, but due to a temperature over 140,000 K it is 282,000 times as luminous as the Sun. With a radius of 89% that of the Sun, it is the smallest known WN star in the Milky Way.

WR 3 is a Wolf-Rayet star located around 9,500 light years away from Earth in the constellation of Cassiopeia.

<span class="mw-page-title-main">WR 9</span> Spectroscopic binary star system in the constellation Puppis

WR 9 is a spectroscopic binary in the constellation Puppis consisting of a Wolf-Rayet star and a class O star. It is around 12,000 light years away.

WR 150 is a Wolf-Rayet star in the constellation of Cygnus. It is one of the early-type carbon sequence (WCE), and is of spectral type WC5. WR 150 is very far from the Earth, being 28,500 light-years from it.

References

  1. 1 2 3 4 5 Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics . 649: A1. arXiv: 2012.01533 . Bibcode:2021A&A...649A...1G. doi: 10.1051/0004-6361/202039657 . S2CID   227254300. (Erratum:  doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  2. ↑ Henden, Arne A.; Levine, Stephen; Terrell, Dirk; Welch, Douglas L. (2015). "APASS - the Latest Data Release". American Astronomical Society Meeting Abstracts #225. 225: 336.16. Bibcode:2015AAS...22533616H.
  3. 1 2 3 4 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. S2CID   56093231.
  4. 1 2 3 Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
  5. 1 2 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. S2CID   119104786.
  6. 1 2 3 4 Sander, A.; Hamann, W.-R.; Todt, H. (2012). "The Galactic WC stars. Stellar parameters from spectral analyses indicate a new evolutionary sequence". Astronomy & Astrophysics. 540: A144. arXiv: 1201.6354 . Bibcode:2012A&A...540A.144S. doi:10.1051/0004-6361/201117830. S2CID   119182468.
  7. 1 2 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". Monthly Notices of the Royal Astronomical Society. 351 (1): 206–214. arXiv: astro-ph/0403482 . Bibcode:2004MNRAS.351..206D. doi:10.1111/j.1365-2966.2004.07771.x. S2CID   2601618.
  8. ↑ 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.
  9. ↑ 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. S2CID   84177572.
  10. ↑ 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. S2CID   118870118.
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