NLTE analysis of the Wolf-Rayet star HD193077 (WN5+abs)

2006 ◽  
pp. 143-144
Author(s):  
W. Schmutz ◽  
W. -R. Hamann ◽  
U. Wessolowski
Keyword(s):  
Rayet Star

scholarly journals GRB 021004: A Possible Shell Nebula around a Wolf‐Rayet Star Gamma‐Ray Burst Progenitor

2003 ◽  
Vol 595 (2) ◽  
pp. 935-949 ◽  
Author(s):  
N. Mirabal ◽  
J. P. Halpern ◽  
Ryan Chornock ◽  
Alexei V. Filippenko ◽  
D. M. Terndrup ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Burst ◽  
Rayet Star

Spectrum of a Dust-embedded Wolf-Rayet Star in Cygnus OB2

1973 ◽  
Vol 241 (106) ◽  
pp. 30-31
Author(s):  
G. E. BROMAGE ◽  
K. NANDY
Keyword(s):  
Rayet Star

scholarly journals Infrared helium emission lines from Cygnus X-3 suggesting a Wolf-Rayet star companion

Nature ◽  
1992 ◽  
Vol 355 (6362) ◽  
pp. 703-705 ◽  
Author(s):  
M. H. van Kerkwijk ◽  
P. A. Charles ◽  
T. R. Geballe ◽  
D. L. King ◽  
G. K. Miley ◽  
...  
Keyword(s):  
Emission Lines ◽  
Rayet Star ◽  
Helium Emission

scholarly journals Molecular gas around the Wolf-Rayet star WR 18 (WN4)

2003 ◽  
Vol 212 ◽  
pp. 732-733
Author(s):  
Anthony P. Marston
Keyword(s):  
Mass Loss ◽  
Optical Emission ◽  
Emission Lines ◽  
Molecular Gas ◽  
Evolved Stars ◽  
Ring Nebula ◽  
History Of ◽  
Optical Ring ◽  
Ring Nebulae ◽  
Rayet Star

Optically observed ring nebulae and H i cavities around Wolf-Rayet stars have enabled us to obtain information on the history of mass-loss associated with these massive evolved stars. However, such studies have left a number of unanswered questions regarding the amount of mass-loss and the conditions of the stars during a sequence of mass-loss phases. Here we discuss the molecular gas environments of the WR star WR 18, which has an associated optical ring nebula NGC 3199. Our observations show that significant amounts of molecular gas appear close to and associated with the star. Mapping of molecular CO near the star shows that molecular materials appear to substantially avoid areas of optical emission and, instead, form a distorted clumpy shell interior to NGC 3199. Molecular emission lines are broader than lines seen in the interstellar medium and suggest the shell is composed of ejecta. This is further corroborated by the enhanced abundances of molecules containing C, N and O. Implications of the observations for the evolution of WR 18 are discussed.

scholarly journals The First Detection of Wolf-Rayet Stars in M31

1982 ◽  
Vol 99 ◽  
pp. 531-537
Author(s):  
Michael M. Shara ◽  
Anthony F. J. Moffat
Keyword(s):  
Star Formation ◽  
Narrow Band ◽  
Massive Stars ◽  
Weak Line ◽  
Band Filter ◽  
Narrow Band Filter ◽  
Rayet Star

A search to continuum magnitude B ∼ 21.5 (MB∼ −3) using a narrow band filter at λ4670å and a wide B-band filter has revealed 21 Wolf-Rayet star candidates in about half the giant Sb galaxy M31. Some weak-line WR stars, particularly WN subtypes, may have escaped detection. These numbers are compatible with the total number of luminous (i.e. massive) stars in M31. Eighteen of twenty confirmed candidate stars in M31 lie in the direction of 0B associations in the ring of prominent star formation 5–16 kpc from the center.

scholarly journals Search for HI Bubbles Around WR Stars: WR 149

1996 ◽  
Vol 169 ◽  
pp. 619-620
Author(s):  
C. Cappa de Nicolau ◽  
V.S. Niemela ◽  
U. Herbstmeier ◽  
B. Koribalski
Keyword(s):  
Interstellar Medium ◽  
Neutral Hydrogen ◽  
Gas Bubbles ◽  
Stellar Winds ◽  
Hydrogen Distribution ◽  
Neutral Gas ◽  
Rayet Star

The interaction of strong stellar winds with the interstellar medium creates large cavities or interstellar bubbles surrounded by expanding outer shells. 21-cm line (HI) observations have revealed the presence of such neutral gas bubbles around several WR stars (e.g. Niemela & Cappa de Nicolau 1991 and references therein; Dubner et al. 1992).Continuing our search for HI bubbles around WR stars, we have analyzed the neutral hydrogen distribution in the vicinity of the Wolf-Rayet star WR149, a highly reddened WN6-7 star located at 6.5 kpc in the direction (l,b) = (89.°53,+0.°65).

scholarly journals A new and unusual LBV-like outburst from a Wolf–Rayet star in the outskirts of M33

2020 ◽  
Vol 492 (4) ◽  
pp. 5897-5915 ◽  
Author(s):  
Nathan Smith ◽  
Jennifer E Andrews ◽  
Maxwell Moe ◽  
Peter Milne ◽  
Christopher Bilinski ◽  
...  
Keyword(s):  
Wind Speed ◽  
Light Curve ◽  
Spectral Type ◽  
Fold Increase ◽  
Small Magellanic Cloud ◽  
Bolometric Luminosity ◽  
Type Spectrum ◽  
Low Metallicity ◽  
Rayet Star ◽  
Luminous Blue Variable

ABSTRACT MCA-1B (also called UIT003) is a luminous hot star in the western outskirts of M33, classified over 20 yr ago with a spectral type of Ofpe/WN9 and identified then as a candidate luminous blue variable (LBV). Palomar Transient Factory data reveal that this star brightened in 2010, with a light curve resembling that of the classic LBV star AF And in M31. Other Ofpe/WN9 stars have erupted as LBVs, but MCA-1B was unusual because it remained hot. It showed a WN-type spectrum throughout its eruption, whereas LBVs usually get much cooler. MCA-1B showed an almost four-fold increase in bolometric luminosity and a doubling of its radius, but its temperature stayed ≳29 kK. As it faded, it shifted to even hotter temperatures, exhibiting a WN7/WN8-type spectrum, and doubling its wind speed. MCA-1B is reminiscent of some supernova impostors, and its location resembles the isolated environment of SN 2009ip. It is most similar to HD 5980 (in the Small Magellanic Cloud) and GR 290 (also in M33). Whereas these two LBVs exhibited B-type spectra in eruption, MCA-1B is the first clear case where a Wolf–Rayet (WR) spectrum persisted at all times. Together, MCA-1B, HD 5980, and GR 290 constitute a class of WN-type LBVs, distinct from S Doradus LBVs. They are most interesting in the context of LBVs at low metallicity, a possible post-LBV/WR transition in binaries, and as likely Type Ibn supernova progenitors.

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