Search Publications
Recombination spectrum and reddening in NGC 1068.
Persson, S. E.; Matthews, K.; Soifer, B. T. +8 more
Measurements of the emission-line intensities of NGC 1068 have been made over the wavelength range extending from rest wavelengths equal to 1216 A to 1.875 micron. The data, plus other available emission-line data, can be explained in terms of a simple model where the emission lines are formed in an H II region, and the line ratios are consistent …
Mass loss from O-type stars.
Conti, P. S.; Garmany, C. D.
We determine mass loss rates for six O-type stars from the violet-shifted absorption profile of the resonance C IV and N V lines, using the IUE satellite and the high-resolution camera. The values are substantially below those of Of stars (which have optical emission lines) of similar luminosity.
International Ultraviolet Explorer observations of M 87.
Capaccioli, M.; Holm, A. V.; Oke, J. B. +1 more
A spectrum of M87 obtained in the 1150-2000 A spectral range by the IUE is discussed. The visual and UV energy distribution of the nucleus of M87 reveals an essentially continuous curve from 1300 to 10,500 A, and a turnup in flux below 2200 A. It is shown that this turnup is not a consequence of scattered light in the instrument, while a plot of t…
IUE ultraviolet spectra and chromospheric models of HR 1099 and UX Ari.
Linsky, J. L.; Simon, T.
IUE spectra in the region 1150-3200 A of the RS CVn-type variables HR 1099 and UX Arietis are presented and analyzed in terms of chromospheric models. Measurements of Mg h and k lines and Ca II H-K and H alpha spectra are indicated which are found not to be correlated with orbital phase or radio flares and which suggest that the strong emission ar…
Ultraviolet absorption by interstellar gas near 30 Doradus
Savage, B. D.; de Boer, K. S.; Koornneef, J.
The IUE was used to obtain high-resolution far-UV spectra (1150-2070 A) of two stars in the 30 Dor H II region in the LMC. Interstellar absorption components are distinguished at +20, +220, +250, and +290 km/s. The +20 km/s component is produced by matter in the Galaxy; the high-velocity components are produced by absorbing gas near or in the LMC.…
Ultraviolet observations of the Cygnus Loop
Raymond, J. C.; Dupree, A. K.; Black, J. H. +2 more
The analysis of IUE observations of a filament on the western edge of the Cygnus Loop yields a shock velocity of about 130 km/sec, significantly higher than the velocity estimated from the optical spectrum. This velocity together with the high forbidden O III/H-beta ratio reported by Miller (1974) indicates that much of the hydrogen recombination …
Highly-ionized species in the interstellar medium.
Raymond, J. C.; Dupree, A. K.; Hartmann, L. W. +1 more
Interstellar absorption lines have been observed toward 25 stars with the International Ultraviolet Explorer satellite. Results are presented for observations of interstellar lines of C III, C IV, N V, Si III, and Si IV. Strong lines of Si IV or C IV are seen toward 11 stars. The strengths of these lines are inconsistent with their formation in th…
The boundary line in the H-R diagram for stellar chromospheres and the theory of convection.
Boehm-Vitense, E.; Dettmann, T.
Ultraviolet emission-line spectra of A, F, and early G stars have been observed with the International Ultraviolet Explorer. For supergiants, classical chromospheric and transition-layer emission is seen only on the red side of the Cepheid instability strip. For luminosity classes III-V, chromospheric emission can be detected for spectral types F2…
Far-ultraviolet spectrophotometry of supernova remnants - Observations and astrophysical interpretation
Benvenuti, P.; Dopita, M.; Dodorico, S.
Far UV spectra obtained with IUE in the supernova remnants Cygnus Loop in the galaxy and N49 and N63 in the LMC have been interpreted using the radiating shock-wave models. Some elemental depletion and a range of shock velocities (approximately 80-130 km/s) are needed to give an adequate description of the observed spectra. Carbon is anomalous, a …
An anomalous ultraviolet extinction curve in the Taurus dark cloud.
Snow, T. P., Jr.; Seab, C. G.
Data from IUE have been used to derive an ultraviolet extinction curve for HD 29647, a B star embedded in the Taurus dark cloud complex. The curve appears normal, except that the 2200 A extinction bump is absent. Arguments are developed to show that this is most likely due to a modification of the grain optical properties through the accretion of …