Zobrazeno 1 - 10
of 73
pro vyhledávání: '"Allan J. Willis"'
Autor:
Paul A. Crowther, Derck Massa, Ken Brownsberger, Alex W. Fullerton, George Sonneborn, Nolan R. Walborn, J. B. Hutchings, Allan J. Willis
Publikováno v:
The Astrophysical Journal Supplement Series. 154:651-672
We present an atlas of far-ultraviolet spectra of 21 Wolf-Rayet (WR) stars in the Galaxy and Large and Small Magellanic Clouds, secured with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. The data cover the wavelength range of 912-1190
Autor:
Alex W. Fullerton, Luciana Bianchi, Anne Pellerin, Paul A. Crowther, Nolan R. Walborn, George Sonneborn, J. B. Hutchings, Allan J. Willis
Publikováno v:
The Astrophysical Journal Supplement Series. 141:443-468
An atlas of the 900-1200 A region in the spectra of 47 OB stars in the Large and Small Magellanic Clouds, observed at high resolution by the Far Ultraviolet Spectroscopic Explorer (FUSE), is presented and discussed. The systematic trends in the numer
Autor:
Paul A. Crowther, Linda J. Smith, Nicole St-Louis, Sébastien Lépine, Anthony F. J. Moffat, Gaghik H. Tovmassian, Matthew J. Dalton, Sergey V. Marchenko, Igor I. Antokhin, Allan J. Willis
Publikováno v:
The Astronomical Journal. 120:3201-3217
We present the most intensive, high-quality spectroscopic monitoring of optical Wolf-Rayet emission lines ever obtained. The Wolf-Rayet star HD 192103 (\WR 135; subtype WC8) was observed in the 5650¨5840 regime alternately from both the William Hers
Autor:
Donald C. Morton, Raymond G. Ohl, Alex W. Fullerton, Luciana Bianchi, Allan J. Willis, George Sonneborn, J. B. Hutchings, K. R. Brownsberger, Derck Massa
Publikováno v:
The Astrophysical Journal. 538:L57-L60
We present an analysis of wind line profiles from Far Ultraviolet Spectroscopic Explorer (FUSE) spectra of two O7 supergiants in the Large and Small Magellanic Clouds (Sk -67°111 and AV 232, respectively). Model fits yield the column densities of S
Autor:
Allan J. Willis
Publikováno v:
Symposium - International Astronomical Union. 193:1-12
This review outlines the impact of observations across the spectrum (X-rays to radio) on our understanding of the basic physical, chemical, wind and mass loss properties of Wolf-Rayet stars. Optical spectropolarimetry indicates that ∼ 15% of the WR
Autor:
Allan J. Willis, Luc Dessart, Peter S. Conti, Patrick W. Morris, André Maeder, K. A. van der Hucht, Paul A. Crowther
Publikováno v:
Monthly Notices of the Royal Astronomical Society. 290:371-379
Autor:
Allan J. Willis
Publikováno v:
Astrophysics and Space Science. 237:145-168
Autor:
Allan J. Willis, T. W. Hartquist
Publikováno v:
Astrophysics and Space Science. 237:3-9
On 1 October 1994, Sir Robert Wilson FRS, CBE became Professor Emeritus in University College London. To commemorate this occasion we decided, with the kind cooperation of Professor J E Dyson in his role as editor of Astrophysics and Space Science, t
Publikováno v:
Symposium - International Astronomical Union. 163:476-480
Our ROSAT observations of γ Velorum obtained over several binary cycles reveal substantial, and repeatable phase-dependent X-ray (0.1—2.5 keV) variations. The derived X-ray light-curve shows a 4 x increase in flux at phase ∼ 0.5, which is shown
Autor:
Linda J. Smith, Allan J. Willis
Publikováno v:
Astrophysics and Space Science. 221:189-196
The WN5 star HD 50896 is a well known variable star but the cause of the variations is uncertain. As part of an extensive observing campaign on HD 50896, 68 spectra were obtained with the AAT and UCL echelle spectrograph over three nights in January