Search Publications
On the presence of OI lambda 1302 emission in Be stars.
Oegerle, W. R.; Peters, G. J.; Polidan, R. S.
The absence of UV O I emission from Be stars is investigated in terms of a model for a circumstellar disk. Observations of the O I 8446 A transition are shown to produce the UV O I triplet 1302.17, 1304.86, and 1306.02 A, which has not been seen. It is demonstrated that the total scattering optical depth in the circumstellar gas is sufficient to e…
Ultraviolet observations of AR Lacertae.
Kiziloglu, U.; Ogelman, H.; Derman, E. +1 more
Short-wavelength (1150-1950 Å) low-resolution and long-wavelength (2000-3000 Å) high-resolution ultraviolet spectra of the RS CVn type binary system AR Lac obtained by IUE are examined. The surface fluxes of short-wavelength chromospheric and transition region lines show average enhancements of 20-200 times to that of the quiet Sun, respectively. …
Astrophysical properties of a luminous Wolf-rayet type object in the core of the extragalactic HII region IC 132 from an analysis of its lambda lambda 1200-6000 A spectrum.
Benvenuti, P.; Dodorico, S.
We discuss the λλ1200-6000 Å spectrum of the ionizing source of the extragalactic H II region IC 132 in M33. The optical spectrum shows a broad λ4686 Å emission: the UV data from lUE show emission lines of N V, N IV, N III, C IV and He II. The WR features suggest an early WN classification with equivalent widths about a factor of 2 weaker than in …
IUE spectrophotometry of X Persei (4U 0352+30).
Bianchi, L.; Perryman, M. A. C.; Bernacca, P. L. +1 more
Seven low-resolution ultraviolet spectra of X Per obtained with the IUE satellite between March 20 - 29, 1980 are analysed. If the star is a member of the Per OB 2 association, with an assumed distance d = 340 ± 20 pc, it follows that the absolute visual magnitude is Mv = -2.3 ± 0.2, the radius R = (4.1 ± 0.6) R_sun; and the mass is M =…
The interstellar 2200 A band : a second catalogue of equivalent widths and preliminary staistical analysis.
Dorschner, J.; Guertler, J.; Friedemann, C. +1 more
A second catalogue of equivalent widths of the interstellar 2200-A band is presented. It is based on spectrophotometric data obtained with the TD-I satellite and supplements the catalogue of Guertler et al. (1982). Both catalogues list a total of 779 stars. The reliability of the derived parameters is analyzed. There is a satisfying agreement with…
Superionization in the AOV star HD 119921.
Franco, M.; Molaro, P.; Morossi, C. +1 more
The IUE high-resolution spectrum of the A0 V star HD 119921 is studied. The anomalous presence of superionized elements (C IV, Si IV) is reported. The authors' analysis excludes classification errors or the presence of a hot companion as the source of the C IV and Si IV lines.
The strength of the C IV 1550 A resonance lines in planetary nebulae.
Wehrse, R.; Koeppen, J.
The strengths of the C IV resonance lines (1548/51 A) in NGC 6210, NGC 7009,. NGC 3242 and IC 2003 obtained from IUE spectra are compared with the predictions of ionization models constructed with standard assumptions. The ratios of observed to computed fluxes range from 0.4 to 0.034. In order to understand these discrepancies, detailed transfer c…
Molecules in celestial objects. IV. IUE observation of CO lines towards Be stars with low reddening.
Tarafdar, S. P.
IUE spectra of two Be stars with small colour excess are presented to show the presence of a number of absorption lines due to A-X transition of 12CO and 13CO. The column densities of 12CO and 13CO towards these two stars and upper limits for these molecules towards three other Be stars and towards plane…
The evidence for shell formation in V1016 Cygni.
Nussbaumer, H.; Deuel, W.
V1016 Cyg is a candidate for being one of the youngest planetary nebulae ever observed. Its evolution is therefore followed with particular attention. The authors have investigated the claim of Feibelman that, early in 1982, a splitting developed in the C IV λ1551 line, indicating shell formation. Careful scrutiny of the spectra shows that claim t…
Detection of a late B star companion of the bright cluster giant C PUP = HD 63032.
Reimers, D.; Groote, D.
IUE observations show that c Pup, the central bright K giant in the open cluster NGC 2451, has a blue companion. A fit of theoretical line blanketed model atmosphere fluxes to the observed energy distribution yields reddening E(B-V) = 0.15 (from λ2200 Å feature), an effective temperature Te = 10,200K, and an angular diameter θ = 0.060. …