Spectrophotometric study of the emission lines ? 4686, 5411 of He II in the eclipsing binary wolf-rayet star V 444 CYG=HD 193576

Astrophysics ◽  
1968 ◽  
Vol 2 (3) ◽  
pp. 167-174
Author(s):  
A. A. Guseinzade
Keyword(s):  
Spectrophotometric Study ◽  
Emission Lines ◽  
Eclipsing Binary ◽  
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.

Detection of polarization structure across the emission lines of the Wolf-Rayet star HD 50896

1979 ◽  
Vol 231 ◽  
pp. L141 ◽  
Author(s):  
I. S. McLean ◽  
G. V. Coyne ◽  
S. J. J. E. Frecker ◽  
K. Serkowski
Keyword(s):  
Emission Lines ◽  
Polarization Structure ◽  
Rayet Star

scholarly journals Recent Photometry of AR Lacertae

1983 ◽  
Vol 71 ◽  
pp. 401-402
Author(s):  
Young Woon Kang ◽  
Frank Bradshaw Wood
Keyword(s):  
Light Curve ◽  
Recent Work ◽  
Emission Lines ◽  
Intrinsic Variability ◽  
Eclipsing Binary

AR Lac is an eclipsing binary of the RS CVn type. The intrinsic variability of one of the components was first announced by Wood (1946) and the presence of sharp H and K emission lines was noted by Wyse (1934). More recent work by Nha and Kang (1982) shows clearly that the light curve varies from year to year. The period is variable.

scholarly journals Call H and K Emission in the Secondary Component of U Cephei

1988 ◽  
Vol 108 ◽  
pp. 219-220
Author(s):  
Akira Okazaki ◽  
Yasuhisa Nakamura ◽  
Jun-Ichi Katahira
Keyword(s):  
Emission Lines ◽  
Secondary Component ◽  
Eclipsing Binary ◽  
Image Tube ◽  
X Ray ◽  
Spectroscopic Observations ◽  
The Third ◽  
Total Eclipse ◽  
Hot Corona ◽  
Made In

U Cephei (V = 6.8–9.0, P = 2.493 d) is an eclipsing binary consisting of a B7V primary and a G8III-IV secondary component. This binary is one of the semidetached Algol systems showing soft X-ray emission which is probably associated with a hot corona surrounding the secondary component (White and Marshall 1983).We made spectroscopic observations of U Cep with the coudé image-tube spectrograph of the 1.9-m telescope at Okayama Astrophysical Observatory on October 14, 1986. We obtained four spectrograms with a dispersion of 16 Å mm-1 covering λ λ3700—4300 Å during the primary eclipse. The first two exposures were made in a total eclipse, while the last two were slightly after the third contact. The CaII H and K emission lines appear clearly in all the spectrograms. Figure 1 represents an intensity tracing of one of these spectrograms.

scholarly journals A New Search for Nebulae Surrounding Wolf-Rayet Stars

1982 ◽  
Vol 99 ◽  
pp. 463-468
Author(s):  
Joy N. Heckathorn ◽  
Frederick C. Bruhweiler ◽  
Theodore R. Gull
Keyword(s):  
Milky Way ◽  
Narrow Band ◽  
Interference Filter ◽  
Emission Lines ◽  
List Type ◽  
Type Number ◽  
Filamentary Structure ◽  
Line Survey ◽  
Ring Nebulae ◽  
Rayet Star

We have used the plate data from An Emission Line Survey of the Milky Way by Parker, Gull and Kirschner(1979) to make a new search for ring nebulae around Wolf-Rayet stars. The Survey consists of narrow-band interference filter direct imagery centered on the emission lines of Hα + [N II] at λ6570, [O III] at λ5007, and [S II] at λ6730. We have discovered at least five new ring nebulae. of the fifteen ring nebulae we were able to detect on the Survey, including our new discoveries, eleven were brighter in the [O III] bandpass than in the Hα + [N II] bandpass, and were filamentary in [O III]. All of the nebulosities we were able to detect were rated on the basis of three criteria: 1)Sharp, filamentary structure present in any or all bandpasses.2)Wolf-Rayet star centered in projected nebulosity, or, if off-center, the segment of the ring nearest the star proportionally brighter than the rest of the ring.3)Absence of any O stars within the nebulosity, or O star in off-centered position not adjacent to the brightest or sharpest portion of the ring.

scholarly journals The changing spectrum and orbital motion of the SMC Wolf-Rayet binary HD 5980

1995 ◽  
Vol 163 ◽  
pp. 254-255
Author(s):  
R.H. Barbá ◽  
V.S. Niemela
Keyword(s):  
Line Width ◽  
Spectral Type ◽  
Orbital Motion ◽  
Emission Lines ◽  
Secondary Component ◽  
Published Data ◽  
Remarkable Change ◽  
Eclipsing Binary ◽  
Spectroscopic Observations ◽  
Type Spectrum

Optical spectroscopic observations of the eclipsing binary WR star HD 5980 in the SMC, obtained during different epochs, show a remarkable change of the WR type spectrum from spectral type WN3-4 to WN7-8. Radial velocities of the WR emission lines from spectra obtained in August 1992, indicate an orbital motion corresponding to the secondary component which is in front of the system during the primary eclipse. We compare the RV curves and phase-dependent line-width variations observed in 1992 with previously published data.

scholarly journals The Wolf-Rayet Eclipsing Binary HD 5980 in the Small Magellanic Cloud

1982 ◽  
Vol 99 ◽  
pp. 317-320
Author(s):  
Jacques Breysacher ◽  
Anthony F. J. Moffat ◽  
Virpi S. Niemelä
Keyword(s):  
Binary System ◽  
Light Curve ◽  
Orbital Period ◽  
Spectroscopic Data ◽  
Magellanic Cloud ◽  
Small Magellanic Cloud ◽  
Eccentric Orbit ◽  
Eclipsing Binary ◽  
Hii Region ◽  
Rayet Star

The Wolf-Rayet star HD 5980, which is probably associated with the bright HII region NGC 346 of the Small Magellanic Cloud, was found to be an eclipsing binary by Hoffmann, Stift and Moffat (1978). Breysacher and Perrier (1980) determined the orbital period, P=19.266±0.003d, of the system whose light curve reveals a strongly eccentric orbit (e=0.47 for i=80°). The behaviour of the light curve outside the eclipses shows that we are dealing with a rather complex binary system. An analysis of the spectroscopic data is presented here.

scholarly journals Ultraviolet Variability of AX Persei

1988 ◽  
Vol 103 ◽  
pp. 303-304
Author(s):  
Joanna Mikolajewska
Keyword(s):  
Optical Spectra ◽  
Radial Velocities ◽  
Roche Lobe ◽  
Emission Lines ◽  
Eclipsing Binary ◽  
Spectroscopic Observations ◽  
Photometric And Spectroscopic Observations ◽  
Red Giant

Recent photometric and spectroscopic observations suggest AX Per might be an eclipsing binary with a period of about 682 days (Kenyon 1986 and references therein). The analysis of optical spectra taken during 1979-1986 has shown periodic minima in all observed permitted lines and a lack of any periodicity in the forbidden lines (Mikolajewska 1987; Mikolajewska & lijima 1987). A comparison of the available radial velocities with these intensity variations shows that the behaviour of emission lines is consistent with the eclipse interpretation, however the minima (especially in HI and HeI) are too broad to be consistent with eclipses even by a Roche lobe filling red giant. In the following, the UV behaviour of AX Per is analysed using IUE spectra collected during the period 1979-1984.

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