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Dust Around Solar Mass Stars
Chary, R.; Zuckerman, B.; Becklin, E. E. +4 more
The DEBRIS project is a search for infrared excess around Sun-like main sequence stars, and other types of stellar targets, using the Infrared Space Observatory. Some results, calibration issues, and changes to our original program are presented. Future platforms for advancing this project after the conclusion of the ISO mission are indicated.
Polar plumes and fine-scale coronal structures - On the interpretation of coronal radio sounding data
Pätzold, M.; Bird, M. K.
Variations in total electron content at high heliographic latitudes, observed during the 1995 solar conjunction of the Ulysses spacecraft when the radio ray path was embedded in the southern coronal hole, were interpreted by Woo and Habbal [1997b] as polar plume structures extending to at least 30 solar radii from the Sun. Somewhat surprisingly, w…
Two spacecraft observations of transient shocks and ejecta in the interplanetary medium
González-Esparza, J. Américo; Bravo, Silvia
We compare Ulysses observations of 22 forward transient shocks (FTSs) and 11 ejecta during the first 19 months of its mission, with observations near Earth by IMP, in order to infer some properties of the propagation of these transient events in the interplanetary medium. We found that 13 of the 22 FTSs detected by Ulysses were also detected by IM…
Imaging Saturns dust rings using energetic neutral atoms
Krimigis, S. M.; Mitchell, D. G.; Roelof, E. C. +3 more
The intense populations of magnetically trap- ped, energetic charged particles that constitute the radiation belts of Saturn's inner magnetosphere are slowly transported towards the planet by radial diffusion processes. Many of these energetic particles interact with the rings of Saturn and ultimately are lost to the magnetospheric system. Energet…
The Red Horizontal-Branch Star HD 17072
Lee, Jae-Woo; Carney, Bruce W.; Habgood, Michael J.
We summarize the results of a spectroscopic analysis of HD 17072, finding it to be a metal-poor ([Fe/H] = -1.17) red horizontal-branch star with T_eff = 5375 K and log g = 2.4. We also derive a radial velocity of 62.8 km s^-1. It has the best determined Hipparcos trigonometric parallax among the metal-poor field horizontal-branch stars and support…
First Results from the ISO-IRAS Faint Galaxy Survey
Neugebauer, Gerry; Soifer, B. T.; Elbaz, David +16 more
We present the first results from the ISO-IRAS Faint Galaxy Survey (IIFGS), a program designed to obtain ISO observations of the most distant and luminous galaxies in the IRAS Faint Source Survey by filling short gaps in the ISO observing schedule with pairs of 12 µm ISOCAM and 90 µm ISOPHOT observations. As of 1997 October, over 500 s…
Optical positions of compact extragalactic radio sources with respect to the HIPPARCOS Catalogue
Costa, E.; Loyola, P.
Optical positions relative to the Hipparcos Catalogue, and therefore within the International Celestial Reference System (ICRS), have been obtained for the optical counterparts of 25 compact extragalactic radio sources (CERS) south of delta ~ +10degr . Most of these sources are being monitored as Benchmark objects for the establishment of a unifie…
AGN watch continuum monitoring of radio-quiet and radio-loud AGN
O'Brien, Paul T.; Leighly, Karen M.
The International AGN Watch has monitored a number of radio-quiet and radio-loud Active Galactic Nuclei - the most luminous objects in the universe. We present a review of the main observational results from the continuum monitoring campaigns, concentrating on those which aim to quantify the simultaneous ultraviolet to X-ray variability characteri…
A Recalibration of the Diffraction Efficiency of the Transmission Grating Spectrometers on EXOSAT
Kahn, Steven M.; Paerels, Frits; Wolkovitch, Debra N.
We describe a recalibration of the diffraction efficiency of the transmission gratings on EXOSAT. This recalibration is required in order to quantitatively interpret the soft X-ray spectra obtained with these instruments on Sco X-1. Because this source is extremely bright, the spectra are sensitive enough to reveal residual systematic effects in t…
STIS Signal-to-Noise Capabilities in the Ultraviolet
Kaiser, Mary Elizabeth; Kimble, Randy A.; Gilliland, Ronald L. +3 more
The Space Telescope Imaging Spectrograph (STIS) was designed as a versatile spectrograph for the Hubble Space Telescope (HST) capable of maintaining or exceeding the spectroscopic capabilities of both the Goddard High Resolution Spectrograph (GHRS) and the Faint Object Spectrograph (FOS) over the broad bandpass extending from the ultraviolet (115 …