WR 111

Last updated
WR 111
Observation data
Epoch J2000.0       Equinox J2000.0
Constellation Sagittarius
Right ascension 18h 08m 28.46870s [1]
Declination −21° 15′ 11.1844″ [1]
Apparent magnitude  (V)+7.82 [2]
Characteristics
Evolutionary stage Wolf-Rayet [3]
Spectral type WC5 [3]
U−B color index −0.38 [2]
B−V color index −0.28 [2]
Astrometry
Proper motion (μ)RA: 0.293±0.129 [4]   mas/yr
Dec.: −1.527±0.107 [4]   mas/yr
Parallax (π)0.5826 ± 0.0759  mas [4]
Distance 1,630+320
−230 [5]   pc
Absolute magnitude  (MV)−4.26 [6]
Details
Semi-empirical model
Mass 13.0 [6]   M☉
Radius 1.99 [6]   R☉
Luminosity 245,000 [6]   L☉
Temperature 89,000 [6]   K
Hydrodynamical model
Mass 13.63 [7]   M☉
Radius 0.905 [7]   R☉
Luminosity282,000 [7]   L☉
Temperature 140,000 [7]   K
Age 4.2 [8]   Myr
Other designations
WR  111, HD  165763, HIP  88856, BD−21°4864, Hen 3-1599, 2MASS  J18082846-2115113
Database references
SIMBAD data

WR 111 (HD 165763) 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.

Contents

History

In 1880, Edward Pickering reported that BD−21°4864 had a spectrum similar to a nova, but it was apparently a non-variable star that had been near 8th magnitude since at least 1849. [9] It was included in Campbell's 1894 paper The Wolf-Rayet stars. [10]

In the Henry Draper Catalogue, BD−21°4864 was listed as entry 165763 with a spectral type of Oa. It was described in 1925 as a "Be star" due to its very strong emission lines, [11] and in 1927 as a class-O star with unusually broad emission features. [12] After the classification of WR stars onto either the nitrogen or carbon sequence, HD 165763 was designated as WC6 and its temperature estimated from the strength of Ov and Civ emission. [13]

In 1968, the WR spectral classes were revised and HD 165763 was used as an example of class WC5. In this catalogue, considered as the fifth catalogue of Wolf Rayet stars, it was designated MR 84. [14] In the sixth WR catalogue, the current naming convention was adopted and this star was numbered as WR 111. [15]

Location

WR 111 is one of the 20 brightest Wolf Rayet stars in the sky. [16] It lies in a rich Milky Way field near to V4381 Sagittarii and HD 165516, but not apparently a member of the associated cluster. [17]

Properties

WR 111 is considered an archetypal WC5 star, having dominant emission lines of Civ, plus strong Ciii emission as well as Oiii, Oiv, and Ov, but not Ovi. [6]

Non-hydrodynamical atmospheric models calculate a "surface" temperature of 89,000 K. The surface in this context is defined as the depth in the atmosphere at which the optical depth reaches 20. This differs from the convention used for many types of star, due to the optically dense stellar winds of WR stars. The corresponding radius is at 2.10 R☉. [6] A more detailed individual study of WR 111 using a hydrodynamical atmospheric model gives a temperature of 140,000 K and a radius of 0.905 R☉. [7] The apparently large difference is due largely to a difference in the depth within the atmosphere at which the radius is defined. [6] The luminosity of WR 111 is similar in both models at 245,000 L☉ - 282,000 L☉, and the masses are found to be 13.0 M☉ and 13.83 M☉, respectively. [7] [6]

The stellar wind from WR 111 is ejecting 20 millionths of the Sun's mass every year at a speed of 2,398 km/s. [6] The mechanism driving the intense stellar wind is found to be an opacity bump deep within the atmosphere caused by highly ionised iron. The winds are then accelerated to high velocity in the outer atmosphere by less highly ionised iron and by carbon and oxygen. [7]

Related Research Articles

<span class="mw-page-title-main">Wolf–Rayet star</span> Heterogeneous class of 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 25</span> Binary star system in the constellation Carina

WR 25 is a binary star system in the turbulent star-forming region the Carina Nebula, about 6,800 light-years from Earth. It contains a Wolf-Rayet star and a hot luminous companion and is a member of the Trumpler 16 cluster. The name comes from the Catalogue of Galactic Wolf–Rayet Stars.

<span class="mw-page-title-main">WR 24</span> Wolf-Rayet star in the constellation Carina

WR 24 is a Wolf-Rayet star in the constellation Carina. It is one of the most luminous stars known. At the edge of naked eye visibility it is also one of the brightest Wolf Rayet stars in the sky.

<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.

<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.

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 93b</span> Wolf-Rayet star in the constellation of Cygnus

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.

<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 135 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 just over four times the radius of the sun, but due to a temperature of 63,000 K it is 250,000 times as luminous as the sun.

<span class="mw-page-title-main">WR 137</span> Star in the constellation of Cygnus

WR 137 is a variable Wolf-Rayet star located around 6,000 light years away from Earth in the constellation of Cygnus.

<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 12</span> Star in the constellation Vela

WR 12 is a spectroscopic binary in the constellation Vela. It is an eclipsing binary consisting of a Wolf-Rayet star and a luminous companion of unknown spectral type. The primary is one of the most luminous stars known.

<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.

<span class="mw-page-title-main">CV Serpentis</span>

CV Serpentis is a binary star system in the equatorial constellation of Serpens. It is a detached eclipsing binary with an orbital period of 29.7 days. The system includes a Wolf–Rayet (WR) star with the identifier WR 113. The system is located at a distance of approximately 6,700 light years from the Sun based on parallax measurements. It is a member of the Serpens OB2 association of co-moving stars.

References

  1. 1 2 van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv: 0708.1752 . Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID   18759600.
  2. 1 2 3 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.
  3. 1 2 Michaux, Yannick J. L.; Moffat, Anthony F. J.; Chené, André-Nicolas; St-Louis, Nicole (2014). "On the origin of variable structures in the winds of hot luminous stars". Monthly Notices of the Royal Astronomical Society. 440 (1): 2–9. arXiv: 1312.2864 . Bibcode:2014MNRAS.440....2M. doi:10.1093/mnras/stt2102. S2CID   118595336.
  4. 1 2 3 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.
  5. ↑ 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.
  6. 1 2 3 4 5 6 7 8 9 10 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 3 4 5 6 7 Gräfener, G.; Hamann, W.-R. (2005). "Hydrodynamic model atmospheres for WR stars. Self-consistent modeling of a WC star wind". Astronomy and Astrophysics. 432 (2): 633. arXiv: astro-ph/0410697 . Bibcode:2005A&A...432..633G. doi:10.1051/0004-6361:20041732. S2CID   18972175.
  8. ↑ Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1): 190–200. arXiv: 1007.4883 . Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. S2CID   118629873.
  9. ↑ Pickering, Edward C. (1880). "Novel Celestial Object". Nature. 22 (569): 483. Bibcode:1880Natur..22..483P. doi: 10.1038/022483c0 . S2CID   4137312.
  10. ↑ Campbell, W. W. (1894). "The Wolf-Rayet stars". Astronomy and Astro-Physics. 13: 448. Bibcode:1894AstAp..13..448C.
  11. ↑ Merrill, P. W.; Humason, M. L.; Burwell, C. G. (1925). "Discovery and Observations of Stars of Class Be". Astrophysical Journal. 61: 389. Bibcode:1925ApJ....61..389M. doi: 10.1086/142899 .
  12. ↑ Payne, Cecilia H. (1927). "Spectroscopic Energy Diagrams for Five Stars of Class O". Harvard College Observatory Bulletin. 844: 17. Bibcode:1927BHarO.844...17P.
  13. ↑ Beals, C. S. (1940). "On the Physical Characteristics of the Wolf Rayet Stars and their Relation to Other Objects of Early Type (with Plates VIII, IX)". Journal of the Royal Astronomical Society of Canada. 34: 169. Bibcode:1940JRASC..34..169B.
  14. ↑ Smith, Lindsey F. (1968). "A revised spectral classification system and a new catalogue for galactic Wolf-Rayet stars". Monthly Notices of the Royal Astronomical Society. 138: 109–121. Bibcode:1968MNRAS.138..109S. doi: 10.1093/mnras/138.1.109 .
  15. ↑ Van Der Hucht, K. A.; Conti, P. S.; Lundstrom, I.; Stenholm, B. (1981). "The Sixth Catalogue of galactic Wolf-Rayet stars, their past and present". Space Science Reviews. 28 (3): 227. Bibcode:1981SSRv...28..227V. doi:10.1007/BF00173260. S2CID   121477300.
  16. ↑ 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.
  17. ↑ Kharchenko, N. V.; Piskunov, A. E.; Schilbach, E.; Röser, S.; Scholz, R.-D. (2013). "Global survey of star clusters in the Milky Way. II. The catalogue of basic parameters". Astronomy & Astrophysics. 558: A53. arXiv: 1308.5822 . Bibcode:2013A&A...558A..53K. doi:10.1051/0004-6361/201322302. S2CID   118548517.
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