Search Publications
On the origin and distribution of C IV and SI IV ions in the neighboring interstellar medium.
York, D. G.; Cowie, L. L.; Taylor, W.
IUE spectrometer observational data are reported on the C IV, Si IV, and N V absorption lines in 46 distant stars at FWHM resolution of 30 km/sec. A simple analytic theory is given for these contributions, including the effects of ionization by a soft X-ray background. While for some of the most distant field stars a photoionized contribution may …
Water production models for comet Bradfield /1979 X/
Feldman, P. D.; A'Hearn, M. F.; Weaver, H. A. +1 more
Whipple (1950, 1951) has proposed that water might be the dominant volatile constituent of the cometary nucleus. The considered investigation is concerned with the clues which observations of the cometary coma provide regarding the parents of the dominant observed coma species. In the early part of 1980, comet Bradfield (1979 X) was observed with …
Ultraviolet emission of the VELA supernova remnant and the Cygnus Loop
Raymond, J. C.; Dupree, A. K.; Black, J. H. +1 more
Ultraviolet emission spectra of several filaments in the Vela supernova remnant and the Cygnus Loop are compared with theoretical models of radiative shocks. Shock velocities range from 85 to 130 km/s. Little or no grain depletion is apparent. Several of the observed filaments deviate from the steady-flow models in the sense that much of the photo…
Ultraviolet and coordinated; ground-based observations of A And.
Altamore, A.; Baratta, G. B.; Friedjung, M. +4 more
High- and low-resolution UV spectrograms of the symbiotic star Z Andromedae were made during 1978-79 with the International Ultraviolet Explorer (IUE) and coordinated with ground-based observations. The spectrograms extend from 1200 to 3341 A and show a rich emission line spectrum with a wide range of ionization energy, from O I, Mg I and II and F…
IUE observations of pre-main-sequence stars. I. MG II and CA II resonance line fluxes for T Tau stars.
Calvet, N.; Giampapa, M. S.; Imhoff, C. L. +1 more
IUE satellite and Lick 3 m reflector image tube scanner measurements of the Mg II and Ca II resonance lines in a sample of T Tauri stars are the basis of a discussion of the Mg II h and k line emission and the Ca II H and K line emission, within the context of stellar chromospheres. Corroborative evidence is presented for the chromospheric origin …
The ultraviolet spectrum of Herbig-Haro object 1.
Brugel, E. W.; Bohm-Vitense, E.; Boehm, K. H.
Continuum and emission line fluxes for HH 1 in the range of 1200-1300 A have been determined using IUE spectra, and it is found that the luminosity of HH 1 in this wavelength interval is slightly larger than 1 solar luminosity, or 20 times greater than for the wavelength range 3200-11,000 A. If averaged over intervals of 100 A, it is shown that th…
Simultaneous X-ray, ultraviolet, optical, and radio observations of the flare star Proxima Centauri
Quinn, P. J.; Linsky, J. L.; Haisch, B. M. +7 more
Results of coordinated program of observations in the X-ray, UV, optical and radio regions of the dM5e flare star Proxima Centauri are presented. Simultaneous observations of the star were obtained on March 6 and March 7, 1979, by the Einstein Observatory IPC, the IUE SWP and LWR cameras at low dispersion, three ground-based optical telescopes in …
A comparison of quasar absorption line systems with absorption by thegalactic halo.
Savage, B. D.; Jeske, N. A.
Milky Way halo and quasar absorption spectra contain a number of remarkable similarities which include mixed ion absorption, a general absence of excited fine structure levels with the possible exception of excited C II, similar column densities, and similar multicomponent line profiles. The extreme sensitivity of UV lines to small amounts of gas …
Interstellar absorption in the MgII resonance line K2 and H2 emissions.
Boehm-Vitense, E.
High-resolution (0.2 A) IUE spectra for the long wavelength range (1800-3000 A) have been studied. It is shown that narrow interstellar Mg II lines are seen in the center of the k2 and h2 emissions from nearby stars with large rotational velocities. For all observed stars, the radial velocity of the central k3 absorption component in the rest syst…
Spectral energy distributions of hot stars with circumstellar dust.
Sitko, M. L.
Combined spectral energy distribution curves of six Ae/Be stars (BD+61 deg 154, AB Aur, V380 Ori, HD 259431, ZCMa, and BD+40 deg 4124), five peculiar shell stars (HD 31648, HD 45677, HD 50138, HD 163296, and HD 190073), and the peculiar central object in the Red Rectangle nebula (HD 44179), obtained with the IUE and a variety of ground-based optic…