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Globular Clusters Photometry With the Hubble Space Telescope. III. Blue Stragglers and Variable Stars in the Core of M3
Schneider, D. P.; Yanny, B.; Guhathakurta, P. +1 more
This paper describes Hubble Space Telescope (HST)/Planetary Camera-I images of the core of the dense globular cluster M3 (NGC 5272). Stellar photometry in the F555W (V) and F785LP (I) bands, with a 1-sigma photometric accuracy of about 0.1 mag, has been used to construct color-magnitude diagrams of about 4700 stars above the main-sequence turnoff …
Multi-site continuous spectroscopy. II. Spectrophotometry and energy budget of exceptional white-light flares on HR1099 from the MUSICOS 89 campaign.
Zhang, X.; de La Reza, R.; Keskin, V. +48 more
We report results from the December 89 multi-site continuous observing campaign (MUSICOS 89) dedicated to the study of surface active structures and flares on the RS CVn-type system HR1099 (=V711 Tau). This system has been observed by up to 17 telescopes around the globe during this campaign. We obtained complete phase coverage for Doppler imaging…
Remarkable Long-Term Changes in the Small Magellanic Cloud Wolf-Rayet System HD 5980
Koenigsberger, G.; Auer, L. H.; Moffat, A. F. J. +3 more
In this paper we report the remarkable changes which occurred in the Small Magellanic Cloud W-R system HD5980 = AB5 between 1978 and 1991. Within this timescale, there has been a systematic enhancement (by factors of 2-10 depending on the line) in the equivalent widths of all emission lines, and a change in the relative strengths of N III, N IV, a…
Eclipse Mapping of the Accreting Magnetic White Dwarf in DP Leonis with HST
Holberg, J. B.; Liebert, James; Schmidt, Gary D. +1 more
We present time-resolved ultraviolet spectrophotometry of the AM Her system DP Leo (E1114+182), obtained with the Faint Object Spectrograph on the Hubble Space Telescope (HST) in 1991 October. During this period, the binary was in a low-activity state. Complementary optical spectrophotometry and spectopolarimetry were obtained in 1991 October and …
The IMF and the extinction law in M 101: HST FOS spectra of extragalactic HII regions.
Benvenuti, P.; Rosa, M. R.
We present medium resolution HST FOS spectra of the ionizing star clusters in four giant HII regions in the spiral galaxy M101, spanning a range in [O/H] from 8.2 to 8.9. The observed energy distributions in the wavelength range 1150A to 8200A are compared to population synthesis models of extremely young star clusters, taking into account the att…
Interplanetary type III radio bursts that approach the plasma frequency: ULYSSES observations.
Hoang, S.; Leblanc, Y.; Dulk, G. A.
We study a set of solar type III radio bursts where the emission is visible from the high-frequency limit of the radio astronomy receiver of the Ulysses Unified Radio and Plasma wave (URAP) experiment down to low frequencies, sometimes near the plasma frequency, and where Langmuir wave spikes are recorded by the radio and/or plasma receivers. For …
Ultraviolet Interstellar Polarization Observed with the Hubble Space Telescope
Martin, P. G.; Walsh, J. R.; Nandy, K. +9 more
We have used the Faint Object Spectrograph of the Hubble Space Telescope to observe interstellar linear polarization from 1300 to 3300 A in two stars with well-studied interstellar polarization at visible wavelenths. The wavelength dependence of linear polarization declines smoothly with decreasing wavelength and is devoid of structure associated …
HST observations of globular clusters in M 31 I. Surface photometry of 13 objects.
Cacciari, C.; Federici, L.; Ferraro, F. R. +8 more
We present the initial results of a study of globular clusters in M 31, using the Faint Object Camera (FOC) on the Hubble Space Telescope (HST). The sample of objects consists of 13 clusters spanning a range of properties. Three independent image deconvolution techniques were used in order to compensate for the optical problems of the HST, leading…
Disk-Resolved Imaging of Io with the Hubble Space Telescope
McGrath, Melissa A.; Paresce, Francesco; Sartoretti, Paola
The first disk-resolved image of Io's trailing hemisphere in the ultraviolet, as well as a visible image of the same hemisphere, has been obtained with the Faint Object Camera (FOC) of the Hubble Space Telescope on March 15, 1992, at a resolution of 210 km. Io shows no large-scale changes in the visible over the 13 years elapsed since the last dis…
Solar and Heliospheric Processes from Solar Wind Composition Measurements
Geiss, J.; Gloeckler, G.; von Steiger, R.
Composition measurements in the solar wind provide important information for solar system science and astrophysics. We show in this report how ion composition data are used to investigate chromospheric and coronal processes. Isotopic abundances in the Sun can best be derived from solar wind measurements. 3He/4He is an isotopi…