Search Publications
A spectrophotometric study of the emission lines in the quiescent dwarf nova Z Chamaeleontis.
Horne, Keith; Marsh, T. R.; Shipman, H. L.
The main goal of the present time-resolved spectrophotometric study of Z Cha is to examine the behaviour of the emission lines during the eclipse of the disc by the secondary star. The observations and data reduction techniques are presented first. Then, the white dwarf spectrum is examined, which produces broad absorption wings around the Balmer …
Nova Aquilae 1982.
Snijders, M. A. J.; Seaton, M. J.; Blades, J. C. +4 more
Observations of Nova Aquilae obtained from the IUE, the Anglo-Australian Telescope, and the Westerbork Synthesis Radio Telescope are discussed. Light curves for B, V, and continuum fluxes at 2800 and 1300 A are presented. Velocities obtained from line profiles indicate the presence of three main gaseous components: a high velocity gas (HVG) compon…
Multiwavelength monitoring of the dwarf nova VW Hydri. I. Overview.
van Paradijs, J.; Heise, J.; Verbunt, F. +7 more
Observations from different wavelength regions are used to investigate outburst mechanisms in VW Hydri. Previous observational data on VW Hydri and the present theoretical understanding of dwarf novae are first reviewed. Observational data from the current data set on ordinary outbursts are found to be self-consistently interpreted both by assumin…
Multiwavelength monitoring of the dwarf nova VW Hydri. III. IUE observations.
Verbunt, F.; Pringle, J. E.; Hassall, B. J. M. +2 more
IUE observations of VW Hyi were obtained between September and November 1984 during three ordinary outbursts, one superoutburst, and quiescence. Progressive fall in UV fluxes is noted during quiescence, and the UV flux lags behind the optical flux during the rise to outburst peak. Initially in the superoutburst, the fluxes rise to the level of an …
The carbon-poor halo planetary nebula DDDM-1.
Clegg, R. E. S.; Torres-Peimbert, S.; Peimbert, M.
The authors have analysed ultraviolet and optical spectra of DDDM-1, a planetary nebula in the galactic halo. Abundances of N, O, S, Ne and Ar are all about a factor 6 lower than solar, while Fe and Mg are deficient by a further factor of 3. No carbon lines were seen in any spectra, and the authors obtain the upper limit C/H < 1.4×10-5
An activity-rotation relationship in F-M dwarfs from MG II H and K flux.
Doyle, J. G.
Mg II h and k fluxes are given for late-type dwarfs whose rotation periods are known. A good correlation between an activity parameter Rhk (represented by the ratio of Mg II h and k luminosity to bolometric luminosity) versus the Rossby-number is found for main-sequence stars F to late M. Both single and binary stars are found to follow…
Radio detection of the Be star psi Persei.
Waters, L. B. F. M.; Lamers, H. J. G. L. M.; Taylor, A. R. +2 more
The authors present the results of a VLA survey for radio emission from a sample of Be stars having strong excess emission in the IRAS bands. Radio emission was detected from one star, ψ Persei. The radio flux density, together with nearly simultaneous ultraviolet and near-infrared observations, argue strongly against a spherically symmetric model…
Delta Andromedae (K3III) : an IRAS source with an unusual ultraviolet spectrum.
Judge, P. G.; Jordan, C.; Rowan-Robinson, M.
The IRAS survey has revealed anomalous cool infrared emission from a number of otherwise apparently normal K stars. IUE spectra of the brightest of these stars, Delta And, which is a spectroscopic binary and optical standard K3 III star, is obtained. The IUE spectra show the unexpected presence of C IV in emission, implying hot material (about 100…
Non-radial pulsations in the extreme helium star HD 160641.
Jeffery, C. S.; Kilkenny, D.; Lynas-Gray, A. E. +1 more
Mean periods of 0.35±0.01, 0.71±0.05, 1.12±0.13 and 1.77±0.34 day are identified from separately analysed photometric observations (obtained in 1979 and 1982) of the extreme helium star HD 160641. Radial velocities were obtained simultaneously with photometry on three nights in 1982. Optical variations are not accompanied by detectable colour chan…
The stellar winds of early-type stars in the Small Magellanic Cloud.
Prinja, Raman K.
Low-resolution IUE spectra are used to investigate stellar winds of early-type stars in the Small Magellanic Cloud (SMC). Model profiles are used to fit well developed P Cygni doublets noted in 25 main-sequence, giant, and supergiant stars. Terminal velocities in the SMC are found to be, generally, up to a factor of 2 lower relative to galactic O …