Search Publications
An alternative procedure for extracting IUE low resolution spectra.
Morossi, C.; Crivellari, L.
This paper presents an alternative procedure which extracts spectra from IUE low resolution images. The -by-line image is scanned perpendicularly to the direction of dispersion . The resulting cross-cuts are then fitted with a known-form analytical function, which consists of a linear base-line describing the background plus as many bands as there…
IUE observations of globular clusters and blue horizontal branch stars
Code, A. D.
This paper presents a review of ultraviolet photometry and spectroscopy of globular clusters and blue horizontal branch stars. Current observations with IUE are placed within the framework of earlier photometric studies carried out by OAO and ANS. In order to provide basic information on the nature of the horizontal branch star, whose light domina…
The UV spectrum of the symbiotic binary AR Pav during eclipse egress.
Hutchings, J. B.; Cowley, A. P.
UV observations intended to study the structure of the compact hot object believed to represent the accreting component of the symbiotic binary AR Pavonis as it emerges from eclipse are presented. Measurements in the spectral region 1200-3200 A were made over a period spanning 11 days of the 20-day egress period by the IUE satellite. Light curves …
Low-resolution MG II H and K observations of solar type stars.
Barry, D. C.; Schoolman, S. A.
Observations with the International Ultraviolet Explorer (IUE) have made possible a comparison between chromospheric radiative loss rates in the Mg II h and k lines and the Ca II H and K lines. Observations made by Stencel et al. (1980) confirm the findings of Linsky et al. (1979) that the chromospheric radiative loss rates in h and k and H and K …
An interactive procedure to solve the background subtraction problems in IUE high resolution spectra: application to the image SWP 4616.
Morossi, C.; Ramella, M.; Santin, P. +1 more
The standard BKG subtraction and blaze efficiency correction in IUE High Resolution Images are unsatisfactory. We have developed an interactive procedure to eliminate these well-known inadequacies. A background statistically constant and a constant point spread function perpendicular to the direction of the dispersion have been assumed. The validi…
IUE observations of supernova remnants
Raymond, J. C.
Ultraviolet spectra of supernova remnants obtained with the IUE satellite provide unique information concerning the shock conditions and elemental abundances in the optically bright filaments. High temperature species such as N V provide diagnostics for shock velocities above 100 km s-1, and strong lines of carbon and silicon in the IUE…
The outer atmosphere structure of three late type stars.
Rego, M.; Fernandez-Figueroa, M. J.; de Castro, E.
Far ultraviolet emission lines of three late type stars, two dwarfs (chi Her and beta Com) and one subgiant (Iota Vir), have been analysed to determine the structure of their outer atmospheres. Emission line fluxes are used to find the emission measure distributions. Using three boundary values of the electron pressure, calculated in a previous pa…
On the ionization and velocity structure of expanding circumstellar envelopes.
Drechsel, H.; Rahe, J.
It is shown that the envelope line profiles formed by the scattering of stellar continuum flux in expanding atmospheres of luminous, early-type and Wolf-Rayet stars are sensitive to the variation of (1) the optical depth in the line, and (2) the velocity gradient of the stellar wind, as a function of radial distance from the star. A theoretical pr…
The IUE spectrum of BD +39 4926.
Saha, A.; Oke, J. B.
IUE spectra of the A- or F-type supergiant BD + 39 deg 4926 have been combined with existing optical data. Comparison with model atmospheres yields an effective temperature of 7750 K, gravity log g of 0.5, and a reddening corresponding to E(B-V) of 0.15. The Mg II wavelength 2800 feature was used to estimate the abundance of Mg(+), and the value o…
The far-UV spectrum of the low-excitation planetary nebula HD 138403.
Surdej, J.; Heck, A.
Two high-resolution far-UV spectra of the low-excitation planetary nebula HD 138403 are analyzed which were obtained with the IUE satellite over the wavelength range from 1170 to 2070 A. It is shown that the nebula's far-UV spectrum comprises a stellar continuum on which are superimposed a few emission lines, numerous interstellar absorption lines…