Search Publications
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 …
A discussion on the nature of the Herbig-Haro object No 1 from its far UV spectrum.
Ortolani, S.; Dodorico, S.
The first far UV observation of an Herbig-Haro object as shown a strong continuum and emission lines of C IV and C II. The intensities of the UV emission lines are not easily interpreted in the framework of the shock wave models which have been proposed for HH objects. The continuum increases toward the high frequencies and is not consistent with …
Ultraviolet spectroscopy with the IUE of OB stars with stellar winds.
Hutchings, J. B.; von Rudloff, I. R.
Spectroscopic observations at high and low resolution (about 2 x 10 to the 4th power, 2 x 10 to the 2nd power) in the 1200-3000 A range are presented for a sample of 21 high-luminosity OB stars. Mass-loss characteristics seen in the strongest line features are examined and discussed. Correlations and comparisons are made with ground-based data and…
IUE observations of circumstellar emission from the late type variable R AQR (M7+pec).
Kafatos, M.; Michalitsianos, A. G.; Hobbs, R. W.
IUE observations of R Aquarii (M7 + pec) have been obtained in low dispersion in order to study its circumstellar emission. Strong permitted, semiforbidden, and forbidden emission lines are identified that are superposed on a bright ultraviolet continuum. From the analysis it is deduced that the strong emission-line spectrum that involves semiforb…
Lyman alpha fluxes of Seyfert galaxies and low-redshift quasars.
Gull, T. R.; Boggess, A.; Wu, C. -C.
The International Ultraviolet Explorer (IUE) was used to measure Ly-alpha fluxes for 13 type 1 Seyferts, one type 2 Seyfert, and one low-redshift quasar. The observed Ly-alpha/H-beta ratio is typically 5 for the type 1 Seyfert galaxies but is 20 for the single type 2 Seyfert. In the Ly-alpha/H-beta versus H-alpha/H-beta diagram, the observations d…
Physical conditions and abundances of CNO elements in NGC 7027.
Panagia, N.; Perinotto, M.; Benvenuti, P.
Spectroscopic observations of NGC 7027 have been obtained with the IUE satellite. The data have been used to investigate the nature of the extinction toward the object, recognizing the existence of three components due to: (1) interstellar, (2) local, and (3) internal dust. The physical conditions in the O III zone have been determined by analyzin…
IUE observations of the Be stars HD 102567 (4U 1145-61), X Per and GAM Cas.
Hammerschlag-Hensberge, G.; Willis, A. J.; Wilson, R. +10 more
The first analysis of ultraviolet spectroscopic observation obtained with the IUE satellite of the Be stars HD 102567, X Per, and Gamma Cas, which all are associated with X-ray sources, is presented. The ultraviolet data for HD 102567 (4U 1145-61) consist of low-resolution spectra covering the wavelength range 1150-3200 A. The ultraviolet fluxes a…
Outer atmospheres of cool stars. VI. Models for EPS ERI based on IUE spectra of C II, MG II, SI II, and SI III.
Linsky, J. L.; Simon, T.; Kelch, W. L.
Observations of the ultraviolet line spectrum of the active chromosphere star, Epsilon Eridani, obtained with the IUE satellite have been analyzed. The coupled statistical equilibrium and radiative transfer equations for the prominent transitions of C II, Mg II, Si II, and Si III. A satisfactory fit to all of the line strengths can be achieved wit…
Ultraviolet, X-ray, and infrared observations of HDE 226868 = Cygnus X-1.
Tanzi, E. G.; Tarenghi, M.; Chiappetti, L. +14 more
During April, May, and July of 1978, HDE 226868, the optical counterpart of Cygnus X-1, was repeatedly observed in the ultraviolet with the IUE satellite. Some X-ray and infrared observations have been made during the same period. The general shape of the spectrum is that expected from a late O supergiant. Strong absorption features are apparent i…
The ultraviolet spectrum of the T Tau star RW Aur.
Giampapa, M. S.; Imhoff, C. L.
Ultraviolet spectra of the T Tauri star RW Aurigae have been obtained with the International Ultraviolet Explorer. Emission lines include Mg II, Fe II, Cr II, Si I, Si II, Si III, Si IV, C II, C IV, and L alpha. The spectrum roughly resembles the solar chromospheric spectrum, but the surface fluxes are 200 times greater. N V and He II appear to be…