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Observations of Uranus, Neptune, and Titan by the International Ultraviolet Explorer

Owen, T.; Caldwell, J.; Butterworth, P. S. +3 more

The ultraviolet spectra of Uranus, Neptune, and Titan do not reveal absorption features at 7-A resolution from 2100 to 3200 A. Upper limits of from 1 to 3 A are set for the equivalent widths of narrow absorptions, which corresponds to a CO/H2 mixing ratio less than 2 x 10 to the -4th in the case of Uranus. The slopes of the continuum reflectivitie…

A classification system for O - B2 stars based on the Si IV and C IV resonance lines.

Wray, J. D.; Parsons, S. B.; Henize, K. G.

Low-dispersion ultraviolet spectra from Skylab Experiment S-019 are used to explore the variations of Si IV and C IV line strengths with temperature and luminosity. These considerations lead to a classification system in which the Si/C ratio is used to discriminate luminosity among the O stars and temperature among the O9-B2 stars of lower luminos…

A remarkable H-alpha outburst in the RS CVn binary SZ PISCIUM - A transient mass-transfer event

Bopp, B. W.

The very unusual spectroscopic behavior of the RS CVn binary SZ Psc (K1IV + F8V; P = 3.97 days) is described. For much of the time the Ha line in the K star appears as a weak absorption feature, presumably partially filled by chromospheric emission. The Hα equivalent width ordinarily shows small variations that may be adequately explained by stell…

Molecular hydrogen ion (H2+) absorption in planetary nebulae.

Feibelman, W. A.; Hobbs, R. W.; Boggess, A. +1 more

Several IUE spectra of planetary nebulae show an absorption feature shortward of 1500 A which is believed to be due to H2(+). The nebulae are excited by stars of spectral type O3-O7 or continuum, and all but one have double-shell structure.

Interstellar abundances derived from IUE data. I. Silicon depletions toward reddened stars.

Joseph, C. L.; Snow, T. P., Jr.

Surveys of abundances for species well suited to IUE's wavelength coverage and spectral resolution are undertaken to acquire interstellar line data for a large number of stars and column densities greater than those of previous instruments. A complex set of interactive computer programs has been developed for the efficient analysis of the IUE data…