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Time dependence of the UV resonance lines in the cataclysmic variables SU UMa, RX And and 0623+71.
Verbunt, Frank; Drew, Janet E.; Woods, A. John
IUE observations of the dwarf novae SU UMa and RX And, and of the nova-like variable 0623 + 71 are presented. At the time of observation, SU UMa and RX And were in outburst. All three systems show variability in the wind-formed UV resonance lines of N V 1240 A, Si IV 1397 A and C IV 1549 A on timescales of hours. The amplitude of variation is smal…
An Astrometric Catalogue of Radio Stars
Walter, H. G.; Hering, R.; de Vegt, Ch.
The first part is presented of a radio star catalog encompassing 186 objects whose selection was guided by the priority criteria of the Hipparchos Input Catalogue Consortium. Since these criteria are well suited to the need for linkage of ground-based optical systems to radio reference frames, this first selection is also considered a suitable bas…
Spectrophotometry of the shell around AG Carinae.
Dufour, Reginald J.; Mitra, P. Mila
Spatially-resolved long-slit spectrophotometry are presented for two regions of the shell nebula around the P-Cygni variable star AG Carinae. The spectra cover the 3700-6800 A wavelength range. Emission-line diagnostics are used to derive extinction, electron temperatures, and densities for various positions in the nebula. The chemical abundances …
The UV spectrum as a signature of the lambda Bootis character.
Gerbaldi, M.; Faraggiana, R.; Boehm, C.
The spectra of all the stars previously classified as Lambda Bootis stars and observed by the IUE satellite at low resolution, in the short wavelength range, are analyzed. The usefulness of this spectral range for classifying the Lambda Boo stars is shown; the UV criteria used to distinguish the Lambda Boo stars from other metal-deficient stars ar…
The Orbit and Companions of the Classical Cepheid FF AQL
Evans, Nancy Remage; Teays, Terry J.; Welch, Douglas L. +1 more
New radial velocities of the classical Cepheid FF Aql have been obtained and combined with previous observations to provide a revised orbit. A companion has been detected at 1800 A in IUE spectra with a spectral type of A9 V to F3 V. If the Cepheid has an evolutionary mass, then the mass ratio is M1/M2 = 3.8. A companion recently detected by speck…
A New Method to Determine the Interstellar Reddening toward WN Stars
Conti, Peter S.; Morris, Patrick W.
The emission lines in Wolf-Rayet stars may be utilized to determine the absorption properties of their line-of-sight interstellar medium. One can measure the line strengths both in terms of the equivalent widths (in units of the continuum) and fluxes. In general, in a comparison of two lines, the equivalent width ratio is extinction independent; i…
The Identification of H 3S + with the Ion of Mass per Charge (m/q) 35 Observed in the Coma of Comet Halley
Reme, H.; Korth, A.; Lin, R. P. +3 more
A sharp peak in the mass spectrum at 35 amu is observed by the heavy ion analyzer on board the Giotto spacecraft just inside the ionopause. This peak is identified with H3S(+) and it is argued that the dominant source of its likely parent molecule (H2S) is the observed distributed source of circumnuclear dust, rather than the central nucleus. In t…
IUE Observations of WX Ceti in Outburst
Downes, Ronald A.
IUE observations of the peculiar dwarf nova WX Ceti roughly two weeks into a rare outburst, the first since 1963, are obtained. The SWP and LWP observations are very similar to other erupting dwarf novae, both in the line and continuum spectrum. The C IV 1549 A doublet displays blueshifted absorption, indicating the presence of a wind which has a …
Ultraviolet and Infrared Monitoring of FG Sagittae during 1982--1989: Evolutionary Status
Fernandez-Castro, Telmo; Cassatella, Angelo; Eiroa, Carlos +3 more
Ultraviolet IUE spectra and infrared JHKL photometry of FG Sge obtained over the period 1982-1989 indicate that the cooling rate of the star observed until about 1980 seems to have stopped and that an increase of the effective temperature may have occurred, this being a significant change in the evolutionary path traced so far. The current spectra…
IUE Observations of PG 1115+080: The He i Gunn-Peterson Test and a Search for the Lensing Galaxy
Tripp, Todd M.; Green, Richard F.; Bechtold, Jill
We have obtained new IUE observations of PG 1115+080 (z_em_ = 1.722), the "triple quasar," in order to carry out the He I Gunn-Peterson test with greater sensitivity and to search for a Lyman-limit discontinuity which could reveal the redshift of the gravitational lens. We find that n_HE I_(z = 1.722) ~ 7x10^11^ h_100_ cm^-3^ at the 3 σ level. We …