WR 1

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WR 1
V863CasLightCurve.png
A visual band light curve for V863 Cassiopeiae, adapted from Chené et al. (2008). [1] The data were taken from November 2003 to February 2004, and different cycles are shown with different colors.
Observation data
Epoch J2000       Equinox J2000
Constellation Cassiopeia
Right ascension 00h 43m 28.39717s [2]
Declination +64° 45′ 35.3847″ [2]
Apparent magnitude  (V)10.54 [3]
Characteristics
Evolutionary stage Wolf-Rayet
Spectral type WN4-s [4]
U−B color index −0.24 [5]
B−V color index +0.37 [5]
Variable type WR [3]
Astrometry
Proper motion (μ)RA: −2.878 [2]   mas/yr
Dec.: −0.702 [2]   mas/yr
Parallax (π)0.3092 ± 0.0139  mas [2]
Distance 10,500 ± 500  ly
(3,200 ± 100  pc)
Absolute magnitude  (MV)−4.9 [6]
Details
Mass 27 [4]   M☉
Radius 2.26 [4]   R☉
Luminosity 760,000 [4]   L☉
Temperature 112,200 [4]   K
Rotational velocity (v sin i)6.5 [7]  km/s
Other designations
V863 Cas, BD+63°83, HD  4004, HIP  3415
Database references
SIMBAD data

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.

Although WR 1 has been recognised as a Wolf-Rayet star since the 19th century, [8] the WR 1 designation does not indicate that it was the first to be discovered. Ordered by right ascension, WR 1 is the first star in the Seventh Catalogue of galactic Wolf-Rayet stars. [9]

WR 1 is a member of the nitrogen sequence of WR stars and has a spectrum with HeII lines much stronger than HeI lines, and NV emission more than twice the strength of NIII, leading to the assignment of a WN4 spectral type. The spectrum has particularly wide HeII, leading to the equivalent classifications of WN4-b (for broad) or WN4-s (for strong). The spectrum also includes CIV and NIV, but no hydrogen lines at all, [10] [11] indicating that WR 1 has already expelled all of its hydrogen through its powerful solar winds.

WR 1 is slightly variable and given the variable star designation V863 Cassiopeiae. The total amplitude of the variations is only 0.09 magnitudes at visual wavelengths. The variations are well-defined with a period of 16.9 days, but the light curve is not sinusoidal and its shape may vary. [12] The variations have been ascribed to a dense asymmetric stellar wind and co-rotating interacting regions in ejected material. [7]

It has been suggested that the variability and an infrared excess could be due to a cool companion, but WR 1 is now considered to be a single star. [11] The WN-b subclass of Wolf-Rayet star are generally thought to be all single, in contrast with the WN-A subclass which have narrow emission on a stronger continuum and are thought to be binary systems with a more conventional hot luminous star. [10]

WR 1 is a possible member of the Cassiopeia OB7 association [9] at a distance of around 1,800  pc , [4] although its Gaia parallax suggests it is more distant. [2] Interstellar extinction is calculated to be 2.1 magnitudes, and at 1,820 pc the bolometric luminosity would be 758,600 L☉. A temperature of 112,200  K is derived from fitting the spectrum, giving a radius of 2.26 R☉. [4]

Related Research Articles

<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 7</span> Star in the constellation Canis Major

WR 7 is a Wolf–Rayet star in the constellation of Canis Major. It lies at the centre of a complex bubble of gas which is shocked and partially ionised by the star's radiation and winds.

<span class="mw-page-title-main">WR 22</span> Eclipsing binary star system in the constellation Carina

WR 22, also known as V429 Carinae or HR 4188, is an eclipsing binary star system in the constellation Carina. The system contains a Wolf-Rayet (WR) star that is one of the most massive and most luminous stars known, and is also a bright X-ray source due to colliding winds with a less massive O class companion. Its eclipsing nature and apparent magnitude make it very useful for constraining the properties of luminous hydrogen-rich WR stars.

<span class="mw-page-title-main">WR 46</span> Star in the constellation Crux

WR 46 is a Wolf-Rayet star in the constellation of the Southern Cross of apparent magnitude +10.8. It is located at 55 arcmin north of Theta2 Crucis. The star is a member of the distant stellar association OB4 Cru, and is around 2,900 parsecs or 9,300 light years from the Solar System.

<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.

<span class="mw-page-title-main">WR 42e</span> Star in the constellation Carina

WR 42e is a Wolf–Rayet star in the massive H II region NGC 3603 in the constellation of the Carina. It is around 25,000 light-years or 7,600 parsec from the Sun. WR 42e is one of the most massive and most luminous stars known.

<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 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.

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.

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">HD 151932</span> Star in the constellation of Scorpius

HD 151932, also known as WR 78, is a Wolf-Rayet star located in the constellation Scorpius, close to the galactic plane. Its distance is around 1,300 parsecs away from the Earth. Despite being a blue-colored Wolf-Rayet star, it is extremely reddened by interstellar extinction, so its apparent magnitude is brighter for longer-wavelength passbands. HD 151932 lies about 22′ west of the open cluster NGC 6231, the center of the OB association Scorpius OB1; it is not clear whether it is a part of the association or not. With an apparent magnitude of about 6.5, it is one of the few Wolf-Rayet stars that can be seen with the naked eye.

<span class="mw-page-title-main">HD 152408</span> Star in the constellation of Scorpius

HD 152408, also known as WR 79a, is a Wolf-Rayet star located in the constellation Scorpius, close to the galactic plane. Its distance is around 2,020 parsecs away from the Earth.

<span class="mw-page-title-main">WR 128</span> Wolf-Rayet star in the constellation Sagitta

WR 128 is a Wolf–Rayet star located about 9,500 light years away in the constellation of Sagitta. A member of the WN class, WR 128's spectrum resembles that of a WN4 star, but hydrogen is clearly present in the star, making it the only known hydrogen-rich WN4 star in the galaxy. However, similar H-rich very early WN stars can be found in the LMC and especially in the SMC, but the only other galactic examples of this are WR 3 and WR 152.

<span class="mw-page-title-main">WR 120</span> Binary star system in the constellation Scutum

WR 120 is a binary containing two Wolf-Rayet stars in the constellation of Scutum, around 10,000 light years away. The primary is a hydrogen-free weak-lined WN7 star, the secondary is a hydrogen-free WN3 or 4 star, and the system is a possible member of the cluster Dolidze 33. From our point of view, WR 120 is reddened by 4.82 magnitudes, and it has the variable designation of V462 Scuti.

<span class="mw-page-title-main">HD 326823</span> Binary star system in the constellation of Scorpius

HD 326823, also known as V1104 Scorpii, is a binary star containing a unique emission-line star, which is in the midst of transitioning to a nitrogen-rich Wolf-Rayet star, as well as being a candidate Luminous blue variable, located 4,142 light years away in the constellation of Scorpius. The primary is very evolved, because it is composed of almost entirely helium, and only 3% of it is still hydrogen, and it has lost most of its mass to the now-very-massive secondary. The underlying mechanisms and mass transfers in the system are comparable to other W Serpentis systems, such as Beta Lyrae and RY Scuti.

References

  1. ↑ Chené, André-Nicolas; St-Louis, N.; Moffat, A. F. J. (June 2008). "Large-Scale Wind Variability of WR1 (HD 4004); Towards the Rotation Rate of Wolf-Rayet Stars". Mass Loss from Stars and the Evolution of Stellar Clusters ASP Conference Series. 388: 157–158.
  2. 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia Collaboration) (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics . arXiv: 2208.00211 . doi: 10.1051/0004-6361/202243940 . Gaia DR3 record for this source at VizieR.
  3. 1 2 Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....102025S.
  4. 1 2 3 4 5 6 7 Sota, A.; Maíz Apellániz, J.; Morrell, N. I.; Barbá, R. H.; Walborn, N. R.; Gamen, R. C.; Arias, J. I.; Alfaro, E. J.; Oskinova, L. M. (2019). "The Galactic WN stars revisited. Impact of Gaia distances on fundamental stellar parameters". Astronomy & Astrophysics. A57: 625. arXiv: 1904.04687 . Bibcode:2019A&A...625A..57H. doi:10.1051/0004-6361/201834850. S2CID   104292503.
  5. 1 2 Pyper, Diane M. (1966). "The Effective Temperatures of Wolf-Rayet Stars as Derived from Their U BV Color Indices Corrected for Emission". Astrophysical Journal. 144: 13. Bibcode:1966ApJ...144...13P. doi:10.1086/148587.
  6. ↑ 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.
  7. 1 2 St-Louis, N. (2013). "Revealing the Asymmetry of the Wind of the Variable Wolf-Rayet Star WR1 (HD 4004) through Spectropolarization". The Astrophysical Journal. 777 (1): 9. arXiv: 1308.5914 . Bibcode:2013ApJ...777....9S. doi:10.1088/0004-637X/777/1/9. S2CID   118553289.
  8. ↑ Campbell, W. W. (1894). "The Wolf-Rayet stars". Astronomy and Astro-Physics. 13: 448. Bibcode:1894AstAp..13..448C.
  9. 1 2 Van Der Hucht, Karel A.; Conti, Peter S.; Lundström, Ingemar; Stenholm, Björn (1981). "The Sixth Catalogue of galactic Wolf-Rayet stars, their past and present". Space Science Reviews. 28 (3): 227–306. Bibcode:1981SSRv...28..227V. doi:10.1007/BF00173260. S2CID   121477300.
  10. 1 2 Smith, Lindsey F.; Shara, Michael M.; Moffat, Anthony F. J. (1996). "A three-dimensional classification for WN stars". Monthly Notices of the Royal Astronomical Society. 281 (1): 163–191. Bibcode:1996MNRAS.281..163S. doi: 10.1093/mnras/281.1.163 .
  11. 1 2 Niedzielski, Andrzej (1998). "The Optical Spectrum of HD 4004 (WN4b). Evidence of Variability". Acta Astronomica. 48: 729. Bibcode:1998AcA....48..729N.
  12. ↑ Chené, A.-N.; St-Louis, N. (2010). "Large-scale Periodic Variability of the Wind of the Wolf-Rayet Star WR 1 (HD 4004)". The Astrophysical Journal. 716 (2): 929. arXiv: 1004.4893 . Bibcode:2010ApJ...716..929C. doi:10.1088/0004-637X/716/2/929. S2CID   118870393.
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