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On the ultraviolet spectrum of AG Peg.
Penston, M. V.; Allen, D. A.
AG Peg has displayed the slowest known nova outburst. Since the system contains an M giant, it can be classified as symbiotic star. Presented are ultraviolet spectra of AG Peg taken with the IUE satellite. A variety of regimes having characteristically different spectral features is found. These include a high-velocity wind in which high-ionizatio…
Dwarf novae in outburst : monitoring WX Hydri with IUE.
Verbunt, F.; Pringle, J. E.; Hassall, B. J. M.
An account is given of the monitoring of WX Hydri with the International Ultraviolet Explorer (IUE) satellite. The data obtained at the beginning of an outburst show that the rise of the optical precedes that of the ultraviolet flux. Observations during quiescence, together with archival data, indicate that the ultraviolet continuum and line fluxe…
EXOSAT MEDA observations of Cygnus X-3.
King, A. R.; Pounds, K. A.; Willingale, R.
Results of a continuous 30.6-hr X-ray observation of Cygnus X-3 with a large area detector are presented. These show the well known, roughly sinusoidal light curve at the 4.8-hr period, with a phase-dependent variability at short time-scales, and associated spectral behavior. The sinusoidal modulation is interpreted as due to electron scattering i…
A superoutburst of the dwarf nova EK Trianguli Australis.
Hassall, B. J. M.
Simultaneous UV and optical spectrophotometry were obtained during several stages of a superoutburst of EK TrA. The observed spectra are compared with steady disc models, built both of blackbodies or Kurucz stellar atmospheres and with optically thin contributions. Atmosphere models predict much lower mass transfer rates than blackbody models. Ass…
Simultaneous X-ray and optical observations of the X-ray dip source X1755-338.
Parmar, A. N.; White, N. E.; Mason, K. O.
Simultaneous X-ray and optical observations have been made of the 'dipping' X-ray source X1755-338 which has a dip recurrence period of 4.4 hr. A sinusoidal modulation of amplitude 0.4 mag is found in the V-band light of the 18 mag optical counterpart of the X-ray source. The period of the optical modulation is consistent with the X-ray dip recurr…
Condensation of dust around the WC7 star HD 192641 (WR 137).
Telesco, C. M.; van der Hucht, K. A.; Longmore, A. J. +4 more
The WC7+ absorption class Wolf-Rayet star WR 137 (=HD 192641) is shown to have brightened significantly in the infrared since 1978, most rapidly between 1983 and mid-1984. This is ascribed to an increase in the mass loss rate and the condensation of dust grains in the stellar wind. At maximum, the dust mass was about 10-8 Msun
The MG II emission in W UMa-type binaries.
Rucinski, S. M.
Low-resolution IUE spectra of the Mg II emission line in eight contact binaries are presented. They are discussed together with the available observations in both resolution modes for other binaries, 15 systems altogether. The relative flux R(Mg II) = f(Mg II)/f(bol), which is known to be independent of the orbital phase, is used as a measure of c…
Abundances of O, Mg, S, Cr, Mn, Ti, NI and Zn from absorption lines of neutral gas in the Large Magellanic Cloud in front of R 136.
Savage, B. D.; de Boer, K. S.; Fitzpatrick, E. L.
The authors have searched six high-dispersion IUE spectra of R136 for weak absorption lines of C I, O I, Mg I, Mg II, Si I, Si II, P I, Cl I, Cr II, Mn II, Fe I, Ni II, Zn II, CO and C2. The absorption detected is from neutral gas in front of the 30 Doradus H II region. For the first time abundances of Mg, Cr, Mn, Ti, Ni, and Zn are det…
Dwarf novae in outburst : simultaneous ultraviolet and optical observations of VW Hydri.
Verbunt, F.; Schwarzenberg-Czerny, A.; Ward, M. +4 more
The authors present simultaneous spectrophotometry of the dwarf nova VW Hydri in the range 1200 - 7000 Å. The main set of observations cover one complete outburst, including the rise and the decline. Comparing these data with data from other outbursts of VW Hyi it is found that all the data can be interleaved. This underlines the similarity in the…
Optical spectroscopy and photometry of the periodic X-ray transient AO 538-66 ( X 0535-668) during an outburst and an OFF state.
Parmar, A. N.; Branduardi-Raymont, G.; Mason, K. O. +2 more
Optical spectroscopy and photometry of the periodic X-ray transient A0538 - 66 are presented. Extensive spectroscopy performed in March 1982 follows the evolution of the multi-component line profiles through an outburst. Particularly distinctive are the broad, asymmetric emission lines which are interpreted as arising in an extensive stellar wind.…