Search Publications
Mass-loss rates for 21 Wolf-rayet stars.
Willis, A. J.; Smith, L. J.; Barlow, M. J.
Mass-loss rates have been derived for 21 WR stars encompassing most subtypes in the WN and WC sequences, from measurements of their infrared free-free fluxes. The resultant mass-loss rates show a range of only a factor of 4. WC stars generally have larger mass-loss rates than WN stars, the mean rates being M(WC) = 4.1 x 10 to the -5th solar mass/y…
Interstellar extinction in the Large Magellanic Cloud.
Nandy, K.; Willis, A. J.; Wilson, R. +2 more
Interstellar extinction in the ultraviolet as a function of position in the Large Magellanic Cloud (LMC) is investigated using an enlarged sample of reddened and comparison stars. With the exception of SK-68-108, the extinction curves of the LMC stars do not show significant variation. The mean extinction curve increases towards 2200 A, with some …
Nova Cygni 1978 - I. The nebular phase.
Snijders, M. A. J.; Seaton, M. J.; Stickland, D. J. +2 more
UV observations of Nova Cygni 1978 have been obtained using IUE on 17 dates between 1978 September 12 and 1979 July 8 inclusive. The discussion includes the interpretation, during the nebular stage, of the UV observations together with optical and IR data from other observers. Analysis of the available data indicates that Nova Cygni 1978 was produ…
Detailed observations of NGC 4151 with the IUE. I. Low dispersion data up to 1979 january.
Tanzi, E. G.; Tarenghi, M.; Perola, G. C. +12 more
Low resolution ultraviolet spectroscopic monitoring of NGC 4151, the brightest Type 1 Seyfert galaxy, with the IUE from February, 1978 to January, 1979, is presented. Data acquisition and reduction are described. Observations were made at seven different epochs. Optimum exposure times, when the object is bright, were found to be 25-30 min and 50-6…
Ultraviolet spectra of planetary nebulae. III. Mass loss from the central star of NGC 6543.
Lutz, J. H.; Seaton, M. J.; Castor, J. I.
An ultraviolet spectrum of the central star of NGC 6543 has been obtained at low dispersion with the short wave camera of the IUE satellite, and the terminal velocity of the stellar wind has been estimated at 2150 km/s. By assuming the effective temperature to be the Zanstra temperature of 43,000 K and the luminosity to be that derived from the ev…
The 1979 outburst of U Scorpii.
Willis, A. J.; Barlow, M. J.; Watson, M. G. +8 more
Optical and ultraviolet observations are presented of the 1979 outburst of the recurrent nova U Sco. For the first time the evolution through outburst is documented photometrically and spectroscopically. Lines of the following ions are identified: H I, He II, C IV, N III, N IV, N V, O IV, O VI and Si IV. No forbidden lines were observed. Mg I was …
Observations and models of H 2252-035.
Jones, D. H. P.; Pringle, J. E.; Hassall, B. J. M. +7 more
The paper presents photometric, spectroscopic, and spectrophotometric observations of H2252-035 over the wavelength range 1200-22,000 A made in 1980. The continuum is well represented by a blackbody of 12,500 K over most of this range. The infrared points (JHK) show evidence for a slightly cooler contribution. There is a significant excess at wave…
Ultraviolet spectra of dwarf solar neighbourhood stars. I.
Doyle, J. G.; Butler, C. J.; Byrne, P. B. +1 more
Short-wavelength IUE spectra of three nearby M-type dwarfs are presented. Two of these stars, Gliese 867 A and AU Mic, are active UV Ceti flare stars and their UV spectra exhibit strong emission lines, characteristic of active chromospheres. The third star, Gliese 825, is a low-activity flare star and its spectrum reveals no chromospheric lines. A…
The chromosphere and corona of Procyon (Alf CMi,F5IV-V).
Jordan, C.; Brown, A.
Observations are reported of Procyon (alpha CMi), an F5 IV-V star, obtained with the IUE satellite at low and high spectral resolutions as part of a program to study the chromospheres and coronae in late-type stars. Methods for analyzing the fluxes and linewidths of alpha CMi and other near main sequence stars are presented, and applied to alpha C…
High-velocity gas associated with the supernova remnant S 147.
Gondhalekar, P. M.; Blades, J. C.; Phillips, A. P.
The star HD 36665 (Ble), which lies behind the old supernova remnant S147, has been observed with the IUE satellite. High-velocity interstellar absorption components of Fe II, Mg I, Mg II, Al II, C II and Si II were detected which originate in gas associated with the remnant. No such high-velocity lines were observed in the IUE spectrum of HD 4011…