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C III observable with IUE.
Nussbaumer, H.; Schild, H.
Theoretical emissivity ratios are presented for the C III UV multiplets at 977, 1176, 1247, 1908, and 2297 A. Proton-ion collision rates for the relevant transitions are calculated by using the semiclassical impact-parameter method as developed by Sahal-Brechot (1969). IUE observations of these multiplets in the planetary nebula NGC 7027, the slow…
Ultraviolet Night Airglow of Venus
Barth, C. A.; Stewart, A. I.
The night airglow spectrum of Venus in the ultraviolet is dominated by the v' = 0 progressions of the gamma and delta bands of nitric oxide. The bands are produced by two-body radiative recombination of nitrogen and oxygen atoms. Since the source of these atoms is in the dayside thermosphere, the night airglow is a tracer of the day-to-night therm…
Chromospheres of the active dwarf binaries EQ Pegasi and xi Bootis.
Dupree, A. K.; Raymond, J.; Hartmann, L. +3 more
Ultraviolet spectroscopic measurements of the M dwarf binary EQ Peg and the G8 V star Xi Boo A have been made with the International Ultraviolet Explorer satellite. High-temperature emission lines (N V, C IV, Si IV) are present with similar strengths in both stars. The surface fluxes of chromospheric and transition-region lines are enhanced relati…
IUE and visual spectrophotometry of 3C 120 and Markarian 79.
Oke, J. B.; Zimmerman, B.
Low-resolution ultraviolet spectra have been obtained with IUE and combined with similar visual observations. The continua of both objects show an excess of flux in the neighborhood of 3000 A. In both objects there appears to be a depression near 2200 A, which is probably the ultraviolet interstellar absorption feature centered at 2175 A. The stre…
The far-UV spectrum of the T Tauri star RU Lupi.
Liseau, R.; Gahm, G. F.; Fredga, K. +1 more
The spectrum of the T Tauri star RU Lupi from 1150 to 3100 A has been observed from the IUE satellite. It is rich in emission lines, seen superimposed on a background continuum and traceable from Ly-alpha to 3100 A. The region from 2000 to 3100 A is dominated by metal line emission of the same nature as previously observed in the optical region. T…
Identification of the UV nightglow from Venus
Feldman, P. D.; Moos, H. W.; Clarke, J. T. +1 more
THE presence of atmospheric ultraviolet (UV) emission between 1,350 and 2,200 Å from the nightside of Venus was first detected by instruments on board the Mariner 5 flyby1. Recently this emission was observed by the UV spectrometer on Pioneer Venus Orbiter at 2,068 Å and identified by Stewart et al.2 as the (0, 0) Cameron ban…
On the high resolution ultraviolet spectrum of P Cygni.
Macchetto, F.; Lamers, H. J. G. L. M.; Cassatella, A. +7 more
The paper discusses ultraviolet spectra of P Cygni in the range of 1150-3200 A obtained at VILSPA from the IUE satellite during April-August, 1978. The spectrum is dominated by blue-shifted absorption lines of singly and doubly ionized metals like Fe, Mn, Ni, Cr, and Ti formed in the expanding envelope. The observations also suggest the presence o…
Ultraviolet spectrophotometry of degenerate stars.
Oke, J. B.; Greenstein, J. L.
Observations of one helium- and three hydrogen-atmosphere degenerates made with the International Ultraviolet Explorer are discussed. Fluxes in the UV give temperatures in good accordance with those determined from the ground and from the ANS satellite data. Profiles of the strong L-alpha absorption in two DA's fit predictions for the expected tem…
Ultraviolet spectroscopic measurements of globular clusters.
Davis, R. J.; Raymond, J. C.; Dupree, A. K. +4 more
Ultraviolet spectra of six globular clusters (M15, M92, NGC 1851, NGC 6624, 47 Tuc, and NGC 6752) have been taken with the International Ultraviolet Explorer satellite in order to investigate the surface brightness distributions in the central regions. The ultraviolet emission indicates composite stellar spectra. Short-wavelength emission (1200-19…
Evidence of SO2 on Io from UV observations
Bertaux, J. L.; Belton, M. J. S.
A quantitative analysis of the UV spectrum of Io obtained by the IUE earth-orbiting telescope in 1978 is performed for the cases of a surface reflectivity which does not exhibit the absorption dip of pure SO2 frost and for a surface reflectivity which reproduces it exactly. The geometric albedo of Io below 320 nm is derived from the observed UV sp…