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Periodicities of Jovian broad-band kilometric radiation observed by Ulysses
Rabl, G. K. F.
Observations of the Unified Radio and Plasma Wave (URAP) instrument onboard the Ulysses spacecraft have been used to analyze periods inherent in the Jovian broad-banded kilometric radio emission (bKOM) between 29 and 47 kHz. It is demonstrated, by using power spectrum analysis and linear prediction time filtering that the long-term fluctuations of…
Focus History of the Hubble Space Telescope - Launch to May 1993
Burrows, C. J.; Hasan, H.; Schroeder, D. J.
Since the launch of the Hubble Space Telescope (HST) the secondary mirror of the telescope has been moved several times in order to collimate the telescope and also to define a position of best focus. In addition to these moves the focus position changes over time because of water desorption by the graphite epoxy in the metering truss. We report h…
Resolved Structure in M33 Supernova Remnants
Blair, William P.; Davidsen, Arthur F.
We present WF/PC narrow band [S II] lambda-6725 images of two M33 supernova remnants obtained with the Wide Field/Planetary Camera on the Hubble Space Telescope. Comparison of these images with ground-based CCD data indicates that HST has resolved the nebular structures into shells or partial shells, permitting improved measurements of the diamete…
Temperatures of Zodiacal dust
Divine, Neil; Grün, Eberhard; Staubach, Peter
Temperatures of interplanetary dust particles have been determined by calculating the termal emission from dust concentrations according to the "Five Populations of Interplanetary Meteroids" model by Divine ( J. geophys. Res., in press, 1993) and matching it with the observed zodiacal thermal emission. Properties of the meteoroid populations are d…
Internal Ultraviolet Explorer Observations of the white Dwarf Nucleus of the Very Old, Diffuse Planetary Nebula, IW-2
Bruhweiler, F. C.; Feibelman, Walter A.
UV low-dispersion spectra of the central star of the faint planetary nebula, IW-2, were obtained with the IUE. The apparent large diameter of the very diffuse nebula, about half that of the moon, as seen on the Palomar Sky Survey plates by Ishida and Weinberger (1987), indicates this object to be potentially quite evolved, and nearby. The IUE spec…
The radial velocity and binarity of HD 153919 (4U 177A T The radial velocity and binarity of HD 153919 (4U 1700-37).
Stickland, D. J.; Lloyd, C.
New measurements of radial velocities from high-resolution lUE spectra of the massive X-ray binary HD 153919 give a velocity amplitude that is markedly smaller than that found in earlier studies, namely 5 km s-1, compared with previous values of around 20 km s-1. If such measurements relate to orbital motion, then the inferre…
BB Virginis: an RR Lyrae in a binary system?
Fernley, J. A.
On Mode Identification in delta Scuti
Cugier, H.; Monier, R.
UV light amplitudes and phase shifts obtained from the IUE observations are discussed for pulsating star delta Scuti. The published ground-based photometric and radial velocity data are also included in the analysis. The observations are compared with model calculations which take into account temperature and pressure changes during pulsation cycl…
The Hyades distance and white dwarf constraints.
Weidemann, V.
It is demonstrated how recent determinations of surface gravity and gravitational red shifts for the Hyades white dwarfs constrain the distance of the cluster for which very discrepant values between trigonometric and kinematic results are presently discussed. If the surface gravity data are correct, the Hyades modulus must be close to m - M = 3.3…
Massive star distribution in external galaxies and starburst regions
Conti, Peter S.
Counts of hot and luminous stars in a number of associations in the Galaxy and Magellanic Clouds enable one to directly investigate the numbers and types of massive stars. There seems to be little, if any, dependence of the slope of the Intial Mass Function, or theM upper on the initial composition of the stars. Indirect estimates of n…