Astronomy:WR 16
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Carina[1] |
| Right ascension | 09h 54m 52.9034s[2] |
| Declination | +57° 43′ 38.2746″[2] |
| Apparent magnitude (V) | 8.36[3] |
| Characteristics | |
| Evolutionary stage | Wolf-Rayet[4] |
| Spectral type | WN8h[4] |
| Variable type | WR[5], ellipsoidal[6] |
| Astrometry | |
| Proper motion (μ) | RA: −9.458[2] mas/yr Dec.: +5.054[2] mas/yr |
| Parallax (π) | 0.438 ± 0.0168[2] mas |
| Distance | 7,400 ± 300 ly (2,280 ± 90 pc) |
| Absolute magnitude (MV) | −5.6[7] |
| Details | |
| Mass | 19[8] M☉ |
| Radius | 11.56[8] R☉ |
| Luminosity | 525,000[8] L☉ |
| Temperature | 44,700[8] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
WR 16 (HD 86161) is a Wolf-Rayet star located in the constellation Carina. It is a massive, luminous, and evolved star in a late stage of evolution, surrounded by a complex nebula formed by its strong stellar winds and past mass ejections. WR 16 is classified as a runaway star due to its high velocity through the interstellar medium.[4]
Physical characteristics
WR 16 is classified as a WN8h star,[4] indicating a hydrogen-rich Wolf-Rayet star dominated by nitrogen emission lines.[11] Its effective temperature of over 40,000 K[8] is hotter than the Sun's typical value of 5,772 K,[12] but cooler than many other WR stars.[8]
WR 16 is a rotating ellipsoidal variable, meaning its brightness and shape change slightly due to rotation.[6]
Runaway status
Motion measurements from the Gaia satellite show that WR 16 moves at about 61 km/s relative to its local interstellar medium, qualifying it as a runaway star. This rapid motion influences the shape of its surrounding nebula.[4]
Nebular structure
WR 16 is surrounded by a bubble-like nebula formed by material ejected in previous evolutionary stages and shaped by its strong stellar winds. Observations reveal a round, bubble-shaped nebula visible in optical and infrared wavelengths. Multiple rings surround the star, likely from episodic mass ejections during its earlier Luminous Blue Variable (LBV) phase. Ionized hydrogen (H II regions) and nitrogen-enriched gas are present, indicating processed stellar material.[4]
Bow shock
Due to its high velocity, WR 16 creates a bow shock—a curved front where its stellar wind collides with the interstellar medium, compressing gas and dust. Radio and infrared imaging confirms the bow shock’s presence.[13][4]
References
- ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific 99 (617): 695. doi:10.1086/132034. Bibcode: 1987PASP...99..695R Constellation record for this object at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ Zacharias, N.; Finch, C. T.; Girard, T. M.; Henden, A.; Bartlett, J. L.; Monet, D. G.; Zacharias, M. I. (2012). "VizieR Online Data Catalog: UCAC4 Catalogue (Zacharias+, 2012)". Vizier Online Data Catalog. Bibcode: 2012yCat.1322....0Z.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 Cichowolski, S; Duronea, N U; Suad, L A et al. (June 2020). "The ISM local to the runaway star WR16". Monthly Notices of the Royal Astronomical Society 495 (1): 417–427. doi:10.1093/mnras/staa1153. Bibcode: 2020MNRAS.495..417C.
- ↑ Samus', N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports 61 (1): 80. doi:10.1134/S1063772917010085. Bibcode: 2017ARep...61...80S.
- ↑ 6.0 6.1 "V0396 Car". AAVSO. https://vsx.aavso.org/index.php?view=detail.top&oid=6149.
- ↑ Rate, Gemma; Crowther, Paul A. (2020). "Unlocking Galactic Wolf-Rayet stars with Gaia DR2 - I. Distances and absolute magnitudes". Monthly Notices of the Royal Astronomical Society 493 (1): 1512. doi:10.1093/mnras/stz3614. Bibcode: 2020MNRAS.493.1512R.
- ↑ 8.0 8.1 8.2 8.3 8.4 8.5 Hamann, W. -R.; Gräfener, G.; Liermann, A.; Hainich, R.; Sander, A. A. C.; Shenar, T.; Ramachandran, V.; Todt, H. et al. (2019). "The Galactic WN stars revisited. Impact of Gaia distances on fundamental stellar parameters". Astronomy and Astrophysics 625. doi:10.1051/0004-6361/201834850. Bibcode: 2019A&A...625A..57H.
- ↑ "WR 16". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=WR+16.
- ↑ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html.
- ↑ Niemela, V.; Gamen, R.; Morrell, N. (2001). "Long term optical spectroscopy of HD 86161 (WR 16)". Eta Carinae and Other Mysterious Stars: The Hidden Opportunities of Emission Spectroscopy 242: 199. Bibcode: 2001ASPC..242..199N.
- ↑ Prša, Andrej; Harmanec, Petr; Torres, Guillermo; Mamajek, Eric; Asplund, Martin; Capitaine, Nicole; Christensen-Dalsgaard, Jørgen; Depagne, Éric et al. (2016). "Nominal Values for Selected Solar and Planetary Quantities: IAU 2015 Resolution B3". The Astronomical Journal 152 (2): 41. doi:10.3847/0004-6256/152/2/41. Bibcode: 2016AJ....152...41P.
- ↑ Duronea, N. U.; Arnal, E. M.; Bronfman, L. (2013). "Carbon monoxide in the environs of the star WR 16". Astronomy and Astrophysics 551: A71. doi:10.1051/0004-6361/201219816. Bibcode: 2013A&A...551A..71D.
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