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An Analysis of the Shapes of Ultraviolet Extinction Curves. III. an Atlas of Ultraviolet Extinction Curves
Fitzpatrick, Edward L.; Massa, Derck
The basic data needed to produce UV extinction curves for a sample of 78 stars, including spectral types, visual photometry, parameters used to produce fits to the UV extinction curves, distances to the program stars, and line-of-sight H I column densities, are presented. The observational and numerical techniques used to obtain the results are di…
The Ultraviolet Calibration of the Hubble Space Telescope. IV. Absolute IUE Fluxes of Hubble Space Telescope Standard Stars
Bohlin, Ralph C.; Gry, Cecile; Holm, Albert V. +1 more
UV fluxes are presented for 37 stars selected as calibration standards for the Hubble Space Telescope (HST). In order to provide data of maximum precision, new absolute calibrations have been derived for the IUE SWP and LWR cameras for point sources in the large apertures, while the sensitivities of the trail and small aperture observing modes rel…
Color Excesses, Intrinsic Colors, and Absolute Magnitudes of Galactic and Large Magellanic Cloud Wolf-Rayet Stars
Vacca, William D.; Torres-Dodgen, Ana V.
Using IUE archival data in the wavelength range 1200-3200 A, we have developed a new quantitative method of nulling the 2175 A interstellar absorption feature observed in stellar spectra and have used this method to determine the color excesses and UV spectral indices for 44 Galactic and 32 Large Magellanic Cloud (LMC) Wolf-Rayet stars. In order t…
A Multiwavelength Study of the Carlson-Henize Sample of Early-Type Galactic Extreme Emission-Line Stars
Feldman, P. D.; Shore, Steven N.; Brown, Douglas N. +3 more
A UV, optical, and radio study of nine early spectral type extreme emission-line Galactic stars from the Carlson and Henize (1979) sample is presented. He 3-407 and He 3-1482 appear to be analogs of the massive evolved B(e) and luminous blue variable stars of the Magellanic Clouds. The sample appears to be confined to a narrow range in spectral ty…
The Problem of the HIPPARCOS Reference Frame
Lattanzi, M. G.; Bucciarelli, B.; Bernacca, P. L.
The basic principles of the realization of a fundamental optical reference frame by using space platforms are outlined in the light of the first of such astrometry projects, i.e., the HIPPARCOS mission of the European Space Agency. The available adaptations of these principles, expected to lead to a HIPPARCOS catalog of more than 100,000 star posi…
Multifrequency Observations of the Optically Active Radio-quiet Quasar GQ Comae. I. Ultraviolet Continuum and Line Variability
Sitko, Michael L.
This paper summarizes the data and preliminary results of a 3 year project to monitor the continuum variability of GQ Com in the satellite ultraviolet and the associated variability of the Lyα and C IV lines. Simultaneous and nearly simultaneous ground-based optical and infrared data were also obtained, but these will be discussed more fully in a …