WR 3

Last updated
WR 3
Observation data
Epoch J2000       Equinox J2000
Constellation Cassiopeia [1]
Right ascension 01h 38m 55.62741s [2]
Declination +58° 09′ 22.6738″ [2]
Apparent magnitude  (V)10.69 [3]
Characteristics
Evolutionary stage Wolf-Rayet [4]
Spectral type WN3-hw [5]
U−B color index −0.86 [3]
B−V color index +0.02 [3]
Astrometry
Radial velocity (Rv)100.00 [6] km/s
Proper motion (μ)RA: −4.200±0.013 [2] mas/yr
Dec.: −1.550±0.012 [2] mas/yr
Parallax (π)0.4376±0.0184  mas [2]
Distance 2,900+520
−390 [4]   pc
Absolute magnitude  (MV)−3.13 [5]
Details
Mass 15 [5]   M☉
Radius 2.48 [5]   R☉
Luminosity 363,000 [5]   L☉
Temperature 89,100 [5]   K
Other designations
HD  9974, WR  3, HIP  7681, 2MASS  J01385562+5809227
Database references
SIMBAD data

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

WR 3 is a member of the nitrogen sequence of WR stars and has a spectrum with strong HeII and NV lines, but weak NIV. HeI lines are very weak or missing, but there are lines of OVI. Unusually, there are lines of hydrogen and absorption components in many lines creating P Cygni profiles. The emission is weaker overall than stars of similar spectral type, and it has often been suggested that WR 3 has a type O binary companion. However, there are no other signs of a companion and it is thought to be a single star with a spectral type of WN3-hw. The "h" and "w" indicate that hydrogen is present and the emission is relatively weak for its class. [7] [8]

Ordered by right ascension, WR 3 was the third star in the Sixth Catalogue of galactic Wolf-Rayet stars. WR 1 and WR 2 are also both early WN stars in Cassiopeiae. [9]

WR 3 is a massive and luminous star. The presence of hydrogen in its spectrum suggests that it is younger than hydrogen-free WR stars and may still be in the process of ejecting the remainder of its hydrogen. The emission lines of heavy elements in its spectrum are produced by strong convection and powerful stellar winds rather than complete loss of the outer layers of the star. [10] The wind has been measured at 2,700 km/s leading to mass being lost at four millionths  M☉ per year. [5]

References

  1. ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific . 99 (617): 695. Bibcode:1987PASP...99..695R. doi: 10.1086/132034 . Constellation record for this object at VizieR.
  2. 1 2 3 4 5 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  3. 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. Bibcode:2002yCat.2237....0D.
  4. 1 2 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.
  5. 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.
  6. ↑ Kharchenko, N. V.; Scholz, R.-D.; Piskunov, A. E.; Röser, S.; Schilbach, E. (2007). "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ˜55000 stars and mean radial velocities of 516 Galactic open clusters and associations". Astronomische Nachrichten. 328 (9): 889. arXiv: 0705.0878 . Bibcode:2007AN....328..889K. doi:10.1002/asna.200710776. S2CID   119323941.
  7. ↑ Hiltner, W. A.; Schild, R. E. (1966). "Spectral Classification of Wolf-Rayet Stars". Astrophysical Journal. 143: 770. Bibcode:1966ApJ...143..770H. doi:10.1086/148556.
  8. ↑ Marchenko, S. V.; Moffat, A. F. J.; Crowther, P. A.; Chené, A.-N.; De Serres, M.; Eenens, P. R. J.; Hill, G. M.; Moran, J.; Morel, T. (2004). "Hydrogen in the atmosphere of the evolved WN3 Wolf-Rayet star WR 3: Defying an evolutionary paradigm?" (PDF). Monthly Notices of the Royal Astronomical Society. 353 (1): 153–161. Bibcode:2004MNRAS.353..153M. doi: 10.1111/j.1365-2966.2004.08058.x .
  9. ↑ 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. ↑ Smith, Nathan; Conti, Peter S. (2008). "On the Role of the WNH Phase in the Evolution of Very Massive Stars: Enabling the LBV Instability with Feedback". The Astrophysical Journal. 679 (2): 1467–1477. arXiv: 0802.1742 . Bibcode:2008ApJ...679.1467S. doi:10.1086/586885. S2CID   15529810.
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