Search Publications
EXOSAT observations of broad iron K line emission from Scorpius X-1.
White, N. E.; Taylor, B. G.; Peacock, A.
Using the Exosat Gas Scintillation Proportional Counter a broad iron K emission line is found to be present in the X-ray spectrum of Sco X-1. The line full width half-maximum (FWHM) is 0.7 keV, independent of the source intensity state. During flaring intervals the line intensity remains constant such that the equivalent width, decreases from 50 e…
IUE observations of beta Pictoris : an IRAS candidate for a proto-planetary system.
Kondo, Y.; Bruhweiler, F. C.
The authors have obtained new IUE observations of β Pic, which was identified from IRAS observations as one of the several candidate stars associated with proto-planetary systems (reported by Aumann and colleagues) and whose near-infrared imagery by Smith and Terrile showed an edge-on disk surrounding the star. New high-resolution spectra, when co…
Interstellar dust in the Large Magellanic Cloud.
Martin, P. G.; Clayton, G. C.
This paper presents extensive observations of the properties of interstellar dust in the Large Magellanic Cloud. Extinction and polarization analysis of 12 reddened stars spread across the LMC shows that in the optical and infrared the dust characteristics are remarkably similar to the Galaxy. The wavelength dependence of the polarization and the …
TT ARIETIS : the low state.
Szkody, P.; Shafter, A. W.; Bond, H. E. +3 more
A comprehensive photometric and spectroscopic study of the low state of the novalike variable TT Ari has been made with observations spanning the UV to IR spectral regions. The roughly 5 mag drop in the system's luminosity from the high state indicates that the mass-transfer rate decreased by more than two orders of magnitude. The drastic reductio…
The ultraviolet spectrum of the companion of Mira (omicron Ceti) : observational evidence for a disk formed by wind accretion.
Reimers, D.; Cassatella, A.
The authors present extensive IUE observations of the companion of Mira (ο Cet B). It is shown that the UV continuum observed with IUE is exclusively due to Mira B at Mira A minimum. The UV continuum appears to vary erratically with a total range of ±30% within days or weeks. The white dwarf companion of Mira A itself is not seen and must be coole…
Ultraviolet spectra of the central stars of large planetary nebulae.
Feibelman, W. A.; Kaler, J. B.
The authors have examined the ultraviolet spectra of 32 planetary nebula nuclei with the IUE. Almost all the nebulae are quite large, with radii greater than 0.2 pc, and all are hot, with Zanstra temperatures ≥70,000K. In most cases, the fluxes at 1500 Å are closely consistent with the visual magnitudes and the assumption of a hot blackbody. The a…
Stellar winds from hot stars in the Magellanic clouds.
Conti, P. S.; Garmany, C. D.
O and B stars in the LMC and SMC have been observed with the IUE in order to compare their winds and mass loss rates with those of their galactic counterparts. It is found that while the wind terminal velocities are generally about 20 percent lower than in galactic stars of the same spectral type, it is not clear that the mass loss rates are signi…
The optical spectrum of hydrogen at 160-350 million gauss in the white dwarf GRW +70 8247.
Liebert, J.; Stockman, H. S.; Angel, J. R. P.
Spectra from the magnetic white dwarf Grw +70 deg 8247 are compared with Roesner et al's. (1984) hydrogen spectrum up to 10 to the 9th G. It is noted that nearly all definite absorption features coincide with transitions whose energy is stationary or nearly stationary, with field strength in the 1.6 to 3.5 X 10 to the 8th G range. The complex spec…
Stellar activity in synchronized binaries. I. Dependence on rotation.
Walter, F. M.; Basri, G.; Laurent, R.
The authors have examined a large sample of late-type binaries with orbital periods from 1 to 100 days for relationships between stellar activity and rotation period, which is assumed to be synchronized with the stellar orbital period. Most of the systems are in the RS Canum Venaticorum class of close binaries. The activity diagnostics were observ…
The ultraviolet spectra of intermediate-redshift quasars.
Huggins, P. J.; Kinney, A. L.; Bregman, J. N. +1 more
In the present sample of 21 intermediate redshift quasars, for which IUE Lyman-alpha line flux and UV continuum observations have been conducted, an extrapolation of the continuum to the X-ray region is noted to fall at least 2-sigma above the measured X-ray flux, at 2 keV, for two-thirds of the sample. The strength of Lyman-alpha is well correlat…