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Blueshifted narrow absorption components in the ultraviolet spectrum of the binary V861 SCO (HD 152667).

Howarth, I. D.

Blueshifted narrow absorption lines have been studied in 14 high resolution IUE spectra of the B0 Ia+B2 V binary V861 Sco. The column densities of C II ions producing the λ1335 P Cygni feature and narrow absorptions have been estimated by profile fitting and velocities measured with respect to interstellar lines. The narrow absorption lines have a…

Optical photometry and UV spectroscopy of the flare star GL 735 (=V1285 Aql).

Doyle, J. G.; Butler, C. J.; Byrne, P. B. +1 more

The authors present optical photometry of flares and possible spot variations on the star Gl 735. Consideration of the energetics of the optical flares suggests that the star may be underactive when compared to other flare stars of the same spectral type. This conclusion is not supported however by an estimate of the radiative loss rate from the l…

An analysis of V861 SCO - II. The stellar wind.

Howarth, I. D.

V861 Sco (= HD 152667) is a close binary with an early-type primary at one time suspected of having a compact (black hole) companion. It is now known that the system comprises a lobe-filling B0Ia star with a B2V secondary. It is pointed out that mass loss from the primary via its stellar wind is of considerable interest, since few close binaries h…

Erratum - Detailed Observations of NGC4151 with IUE - Part Three - Variability of the Strong Emission Lines from 1978FEB to 1980MAY

Tanzi, E. G.; Tarenghi, M.; Perola, G. C. +8 more

IUE observations of two extremes among contact binaries : AW Ursae Majoris and SW Lacertae.

Pringle, J. E.; Vilhu, O.; Rucinski, S. M. +1 more

The authors present IUE observations of AW UMa and SW Lac. These stars are the most extreme representatives of the A- and W-types of W UMa stars and might therefore be expected to differ most in their properties. The authors find that the stars are similar in their transition region emission (N V, C IV, Si IV) but differ markedly in their chromosp…

RZ Gru - a UX UMa 'disc star'.

Stickland, D. J.; Kilkenny, D.; Kelly, B. D. +4 more

The star RZ Gruis is confirmed as a cataclysmic variable. Its ultraviolet spectrum suggests that it belongs to the UX UMa subclass in which an optically thick disc is maintained at outburst state; coordinated optical and UV photometry show changes of about one magnitude on a time-scale of months in addition to smaller variations on a scale of minu…

Variable ultraviolet emission in SY Muscae.

Kafatos, M.; Michalitsianos, A. G.

The results of continued IUE monitoring of the symbiotic variable SY Muscae, following an earlier report of a radical enhancement in UV emission from the star, are reported. Over the course of one year, the prominent emission lines of N V, O V, C IV, and He II appear to be gradually decreasing in absolute intensity. This appears to coincide with a…

IUE observations of RS CVn-like binary sigma Corona Borealis.

Tarafdar, S. P.; Agrawal, P. C.

High and low resolution IUE observations of the triple system sigma CrB are presented. The spectra show the presencee of chromospheric (O I, Si II, Mg II) and transition region lines (He II, C II, C IV) in emission. The surface fluxes of these lines are orders of magnitude higher than those observed in the sun but are comparable to their values in…

The C/O abundance ratio in the planetary nebula IC 2501.

Adams, S.; Goharji, A.

The detection of a silicon carbide feature in the infrared spectrum of the planetary nebula IC 2501 suggests that the nebular envelope is carbon rich (Aitken and Roche 1982). The authors have observed IC 2501 with the IUE satellite and have combined these observations with optical measurements in order to analyse the physical conditions and abunda…

Spectrophotometry of early type supergiants in the Large Magellanic Cloud.

Nandy, K.; Houziaux, L.; Thompson, G. I. +1 more

A sample of LMC supergiants ranging in type from O5 to A1 has been subjected to equivalent width measurements of major stellar features in the visible and UV spectral regions, using methods that are entirely numerical and to the greatest possible degree free from subjective estimates. LMC member results are compared with those obtained for their g…