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The eclipse of epsilon Aurigae in the ultraviolet.
Ferluga, S.; Hack, M.; Boehm, C.
Ultraviolet low-resolution spectra of Epsilon Aurigae (F0Ia +) have been taken with IUE during the partial and total phase of the present eclipse; they are compared with a set of corresponding pre-eclipse spectra. The following conclusions are derived. A hot component, dominant in far UV, is associated with the extended body that eclipses the prim…
Spectroscopic analysis of the suspected AM star 15 Vulpeculae.
Takeda, Y. -I.
The suspected Am star 15 Vul is characterized using the ATLAS-6 model-atmosphere program of Kurucz (1979) and spectrograms (resolution 10 and 4 A/mm) obtained with the coudespectrograph of the 1.88-m reflector at Okayama Astrophysical Observatory during September and October 1981; comparison stars are 28 And and 9 Aur. The data and calculated abun…
Ultraviolet and visible flare observations of EQ Pegasi B.
Raymond, J. C.; Baliunas, S. L.
EQ Peg AB (dM43+dM5.5e) was monitored in the visible at the Whipple Observatory and ultraviolet with IUE on September 2, 1981. In the visible spectrophotometry of EQ Peg B the H-beta emission strengthened by a factor of 2 relative to the nearby stellar continuum within a few minutes and decayed over an hour. This flare in EQ Peg B was coincident w…
IUE observations of the X-ray binary A0538-66 : spectroscopic study of a strange stellar system.
Howarth, I. D.; Willis, A. J.; Prinja, R. K. +1 more
The results of extensive IUE monitoring of the optical counterpart of the recurrent periodic LMC X-ray transient A0538-66 are presented. Even when the system is not in outburst dramatic spectral variations occur, accompanied by changes in the temperature and surface area of the continuum emitting region. It is shown that, in spite of these variati…
The UV spectrum of the Seyfert 1 galaxy NGC 7469.
Westin, B. A. M.
Results from an investigation of thirty-two IUE spectra of the Seyfert 1 galaxy NGC 7469 are presented. During the observation period, from June 1978 to December 1982, the continuum at 1500 Å (observed wavelength) has been found to vary by a factor of about two. The strong emission lines are broad (FWZI 10,000 - 25,000 km s-1) and asymm…
Ultraviolet interstellar absorption toward stars in the Small Magellanic cloud. II. SK 159.
Fitzpatrick, E. L.
On the basis of a study of high-dispersion spectra of stars in the Large and Small Magellanic Clouds (LMC and SMC) obtained with the International Ultraviolet Explorer (IUE) satellite, Savage and de Boer (1979, 1981) have detected the Milky Way halo gas. The existence of gaseous coronae around both the LMC and SMC was also suggested. The evidence …
The far-ultraviolet energy distribution of Sirius B from Voyager 2.
Wesemael, F.; Holberg, J. B.; Hubeny, I.
Observations of Sirius obtained with the Voyager 2 ultraviolet spectrometer clearly reveal the presence of flux from the white dwarf Sirius B at wavelengths between 950 and 1100 A. These observations are in good agreement with all previous ultraviolet observations of Sirius B, and in particular with the IUE observations of Boehm-Vitense, Dettmann,…
SI III emission line strengths in low density plasmas.
Dufton, P. L.; Keenan, F. P.; Kingston, A. E.
Theoretical emissivity ratios appropriate to homogeneous optically thin plasmas are presented for the Si III lines at 1883 and 1892 Å. These lines are a useful density diagnostic for Ne ≥ 104cm-3, their use being illustrated for the planetary nebulae NGC 7662 and V1016 Cygni.
The presence of Si3+ and C3+ in the wind of AB Aur.
Talavera, A.; Catala, C.
The Herbig Ae variable AB Aur (spectral type A0) exhibits a line spectrum characteristic of a stellar wind. IUE observations of the Si IV and C IV resonance lines in AB Aur are reported. These lines are strong and in absorption. Two models can explain the presence of Si3+ and C3+ in the wind of AB Aur: a "remote chromosphere"…
Accretion of mass in Algol.
Molaro, P.; Cugier, H.
Several high resolution IUE spectra of Algol taken in 1978 and 1979 are analysed. Variable additional absorption components for the ultraviolet resonance lines of Mg II, Al III, and Si IV are detected. The additional components show eclipsing effects indicating that they originate in a region near the primary star, Algol A. Moreover, their behavio…