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Episodic mass loss and narrow lines in Gamma Cassiopeiae and in otherearly-type stars.
Howarth, I. D.; Hammerschlag-Hensberge, G.; Barr, P. +1 more
High-resolution ultraviolet spectra obtained with the IUE of the B0.5 IVe star γ Cas have revealed conspicuous changes in the profiles of the resonance doublet lines of C IV, N V, and Si IV. In 18 out of the 28 available spectra, narrow absorption components of varying strengths are found at the blueshifted side of the rest wavelength. The central…
The ionization structure of planetary nebulae. III. NGC 7009.
Barker, T.
Barker has found (1980, 1982) that combined optical and ultraviolet observations in several different regions of one planetary nebula, NGC 6720, can be used both to estimate particularly reliable total elemental abundances and to learn more about the physical conditions in the nebula. It is important, however, that all the observations be made in …
Mass loss, levitation, accretion and the sharp-lined features in hot white dwarfs.
Kondo, Y.; Bruhweiler, F. C.
A study has been conducted of eight white dwarfs, including seven DA and one He-rich types. The study is based on high-resolution observations conducted with the aid of the International Ultraviolet Explorer. Four of the dwarfs show features related to heavy elements which are not interstellar in origin. It is tentatively suggested that, at least …
The ultraviolet spectrum of the Seyfert galaxies NGC 3516 and NGC 5548.
Ulrich, M. H.; Boisson, C.
The observation of the UV spectrum of Seyfert nuclei has made it possible to conduct a comparison of the UV spectra of active nuclei over a wide range of absolute luminosities. In a study of the two Seyfert galaxies NGC 3516 and NGC 5548 with the International Ultraviolet Explorer (IUE) satellite, Boggess et al. (1978) have found that remarkable v…
IUE observations of Markarian 3 and 6 : reddening and the nonstellar continuum.
Malkan, M. A.; Oke, J. B.
The authors have used IUE visual and infrared observations to study the spectra of the Seyfert 2 galaxies NGC 1068 and Markarian 3, and the Seyfert 1.5 galaxy Markarian 6. The starlight in these galaxies is reddened by 0.01, 0.18, and 0.06 mag in EB-V, respectively; the forbidden lines are reddened by 0.29, 0.27, and 0.27 mag, respectiv…
Rocket detection of ultraviolet emission from neutral oxygen and sulfur in the IO Torus
Durrance, S. T.; Feldman, P. D.; Weaver, H. A.
Ultraviolet spectra (1150-1750 Å) of the Io plasma torus were obtained using a rocket-borne telescope and spectrometer in 1981 May. The spectra show emissions of neutral oxygen and sulfur as well as the first three ionization states of sulfur. A comparison with IUE spectra indicates that these emissions may have different spatial distributions or …
High-velocity iron absorption lines in supernova remnant 1006.
Gull, T. R.; Sarazin, C. L.; Wu, C. -C. +1 more
The very strong, broad absorption lines of a sdOB star continuum shown in the International Ultraviolet Explorer spectrum of the Schweizer-Middleditch star projected near the center of supernova remnant SNR 1006 are investigated. It is found that strong Fe(+) resonance absorption lines are present whose centers show zero radial velocity while thei…
Absorption by halo gas in the direction of M 13.
Savage, B. D.; de Boer, K. S.
A high velocity cloud in the direction 1 = 59 degrees, b = 41 degrees is detected in absorption at approximately -80 km/s in high dispersion IUE spectra of the blue star Barnard 29 in the globular cluster M13. The cloud is also seen in the H I 21 cm emission data of Kerr and Knapp (1972). Its radial velocity agrees with Giovanelli's data (1980, 19…
Do all barium stars have a white dwarf companion ?
Lambert, D. L.; Dominy, J. F.
International Ultraviolet Explorer short-wavelength, low-dispersion spectra were analyzed for four barium, two mild barium, and one R-type carbon star in order to test the hypothesis that the barium and related giants are produced by mass transfer from a companion now present as a white dwarf. An earlier tentative identification of a white dwarf c…
Ultraviolet interstellar absorption toward HD 5980 in the Small Magellanic Cloud.
Savage, B. D.; Fitzpatrick, E. L.
Individual high-dispersion International Ultraviolet Explorer (IUE) spectra of extragalactic stars are noisy because of the long exposure times required and the inherent limitations of the IUE detectors. A program has, therefore, been undertaken to obtain multiple ultraviolet spectra of the brightest Magellanic Cloud stars in order to produce comp…