WR 121-16
| Observation data EpochJ2000.0EquinoxJ2000.0 | |
|---|---|
| Constellation | Scutum |
| Right ascension | 18h51m39.7102s[1] |
| Declination | −05° 34′ 51.066″[1] |
| Apparent magnitude(V) | 14.02 (13.95 - 14.14)[2] |
| Characteristics | |
| Spectral type | WN7o/WC[2] |
| Apparent magnitude(J) | 11.369[3] |
| Apparent magnitude(K) | 10.609[3] |
| Astrometry | |
| Proper motion(μ) | RA:−2.450[1]mas/yr Dec.:−6.943[1]mas/yr |
| Parallax(π) | 0.0776 ± 0.0156mas[1] |
| Distance | 23,190[2]ly (7,110pc) |
| Absolute magnitude(MV) | −3.955[2] |
| Details[2] | |
| Mass | 7.1+1.7 −1.1M☉ |
| Radius | 4.14+1.4 −1.3R☉ |
| Luminosity | 75,900+36,300 −22,200L☉ |
| Temperature | 47,000+9,000 −5,000K |
| Other designations | |
2MASSJ18513970-0534510 | |
| Database references | |
| SIMBAD | data |
WR 121-16is a transitionalWolf-Rayet starin the constellation ofScutum,near theWild Duck Cluster(M11). It is located in theFar 3 kpc Armof theMilky Way.It is very dim from Earth, having anapparent magnitudeof about 14,[2]from being so reddened by interstellar extinction, and its distance of over 23,000 light years.[4]It is one of the dimmest known conventional Wolf-Rayet stars, with a luminosity of less than 76,000 times that of theSun.WR 121-16 varies irregularly between magnitudes 13.95 and 14.14.[2]
WR 121-16 is a recent addition to theWolf-Rayet Star Catalogue,being the 667th star added. It was discovered in August 2020.
Discovery
[edit]WR 121-16 was originally discovered as a ‘by-product’ of the LAMOST testing observations during the full moon nights, when the telescope was pointing to the open clusterM11,with WR 121-16 being about 42′ 24 apart from the centre of M11.[2]
Features
[edit]WR 121-16 is one of a few transitional Wolf-Rayet stars, which display both carbon and nitrogen emission, with aspectral typeof WN7o/WC. Modelling thespectrumshows that WR 121-16 is not very luminous at all, with aluminosityof just 75,900L☉,much less than most Wolf-Rayet stars. WR 121-16 has just over 7solar masses,nearly all of which is helium. 1.5% of the star is composed of nitrogen, and 0.2% of it is composed of carbon.[2]
Strongstellar winds,typical of Wolf-Rayet stars, with aterminal velocityof 1,000 kilometers per second are causing WR 121-16 to lose 10−4.97M☉/year,[2]much more than the Sun's (2-3) x 10−14solar masses per year. The winds are so dense that thephotosphereof the star is not visible. Its radius is defined for consistency with other Wolf-Rayet stars as being at anoptical depthof 20, at about 4R☉.A "transformed" radius at an optical depth of 2/3, more comparable to other types of star, is at about 6R☉.[2]
References
[edit]- ^abcdeBrown, A. G. A.;et al. (Gaia collaboration) (2021)."GaiaEarly 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.S2CID227254300.(Erratum:doi:10.1051/0004-6361/202039657e).Gaia EDR3 record for this sourceatVizieR.
- ^abcdefghijkZhang, Wei; Todt, Helge; Wu, Hong; Shi, Jianrong; Hsia, Chih-Hao; Wu, Yuzhong; Wu, Chao gian; Zhao, Yongheng; Zhang, Tianmeng; Hou, Yonghui (2020-10-12)."A New Transition Wolf-Rayet WN/C Star in the Milky Way".The Astrophysical Journal.902(1): 62.arXiv:2008.08205.Bibcode:2020ApJ...902...62Z.doi:10.3847/1538-4357/abb0e7.ISSN1538-4357.S2CID221172973.
- ^abCutri, 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.
- ^"Wolf-Rayet Star Catalogue".pacrowther.staff.shef.ac.uk.Retrieved2021-03-24.
