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IUE ultraviolet spectroscopy of stars in the Magellanic Clouds.

Hutchings, J. B.

Low dispersion IUE spectra of seven hot supergiants in the Large Magellanic Cloud and one in the Small Magellanic Cloud are presented. Stellar winds are present in all the stars, but the resonance lines have weak or no emission and probably have lower terminal velocities than galactic counterparts. Spectral energy distributions are used to derive …

IUE observations of RW Hya (gM2+pec).

Kafatos, M.; Michalitsianos, A. G.; Hobbs, R. W.

Analysis of the intense UV continuum observed between 1100 and 2000 A suggested that observations of the late type star RW Hya is a binary system in which the secondary is the central star of a planetary nebula. The UV spectrum is characterized by semiforbidden and allowed transition lines, of which the C IV doublet is particularly strong. Tidal i…

Interstellar C IV and SI IV column densities toward early-type stars.

Kondo, Y.; McCluskey, G. E.; Bruhweiler, F. C.

Equivalent widths and deduced column densities of Si IV and C IV are examined for 18 early-type close binaries, and physical processes responsible for the origin of these ions in the interstellar medium are investigated. The available C IV/Si IV column density ratios typically lie within a narrow range from 0.8 to 4.5, and there is evidence that t…

An absorption line in the ultraviolet spectrum of 40 ERI B.

Greenstein, J. L.

Two excellent low-resolution spectra show an absorption line of equivalent width 3 A, near 1391 A, in the typical DA (hydrogen atmosphere) white dwarf 40 Eri B. The line is confirmed by a high-resolution spectrum and is the first seen in any DA star. Ultraviolet fluxes and the profile of Lyman-alpha confirm an effective temperature near 17,000 K. …

IUE spectra of the jet and the nucleus of M 87.

Tarenghi, M.; Perola, G. C.

IUE spectra from 1300 to 3000 A of the jet and the nucleus of M87 are presented. The flux detected with the 10 x 20 arcsec aperture positioned on the jet is consistent with the extrapolation of the optical power law spectrum of the bright complex of knots A plus J plus B, plus a contribution of diffuse light from M87. The spectrum of the nucleus d…

X-ray and ultraviolet spectroscopy of CYG X-1 = HDE 226868.

White, N. E.; Kondo, Y.; McCluskey, G. E. +5 more

Observations of Cygnus X-1 with the solid-state spectrometer on the Einstein Observatory are presented. The X-ray spectra of two intensity dips viewed near superior conjunction did not exhibit increased photoelectric absorption. Rather, the data support a model in which an increase in the electron-scattering optical depth modifies both the observe…

Observations of the quiescent corona, transition region, and chromosphere in the dMe flare star Proxima Centauri.

Linsky, J. L.; Haisch, B. M.

IUE low-dispersion spectra of four luminous stars in symmetric nebulae.

Johnson, H. M.

The stars and nebulae are HD 56925 in NGC 2359, + 60 deg 2522 in NGC 7635, AG Car in its nebula, and 209 BAC in M1-67. A discussion of known properties of these systems precedes the IUE data, which are tabulated with types and identifications of significant line features and velocities of ultraviolet-displaced absorption features. Weaver et al.'s …

Ultraviolet spectrum synthesis of the helium white dwarf Ross 640.

Cottrell, P. L.; Greenstein, J. L.

The UV spectrum of the He-rich white dwarf Ross 640 was used to derive Mg, Si, and Fe abundances by a spectrum synthesis technique. The values obtained were: Mg/He = 6.8 x 10 to the -8th; Si/He = 3.2 x 10 to the -8th; Ca/He = 7.6 x 10 to the -10th; and Fe/He = 2.0 x 10 to the -9th. The abundances indicate the operation of diffusion processes withi…

Ultraviolet spectroscopic observations of VV Cep.

Dupree, A. K.; Holm, A. V.; Black, J. H. +1 more

Observations with the International Ultraviolet Explorer satellite (IUE) of the recent egress of the eclipsing binary VV Cep(M2Iabep + B) are presented. Egress in the ultraviolet lagged behind the visible egress by 2 to 3 months, as a result of higher opacity of the M star atmosphere in the ultraviolet. Shortly after visible egress, the low-disper…