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Upper limits to Jovian hard X radiation from the Ulysses gamma ray burst experiment
Hurley, K.; Sommer, M.; Waite, J. H.
We describe the first in situ search for Jovian X radiation with a dedicated X ray instrument. Upper limits to Jupiter's X ray power in the 27-48 keV range are presented using data taken by the gamma ray burst experiment on the inbound Ulysses trajectory, at distances between 163 and 110 RJ. The data were analyzed using three methods fo…
A development of double star astronomy after Hipparcos
Lampens, P.; Dommanget, J.
Now that the HIPPARCOS satellite safely revolves on his 'degraded' orbit - after the exploit of the ESA technicians to rescue it from the faulty ignition of its apogeum boost motor - and regularly provides the information needed for reaching the initial aim of the project, one may turn to examine the possible applications of the finalHipparcos Cat…
The low-frequency interplanetary radiation
Kurth, W. S.
Observations of the low-frequency interplanetary radiation have continued, although no major activity has begun since mid-1991. Theoretical work has been completed which suggests that the long-speculated source at the termination shock is feasible and could at least qualitatively account for several aspects of the observations, although some diffi…
Initial results from the solar flare X-ray observations with ulysses
Hurley, K.; Sommer, M.; Kane, S. R. +1 more
The Solar X-Ray/Cosmic Gamma-Ray Burst Experiment aboard the Ulysses spacecraft measures hard X-ray spectra in the nominal energy range 15-150 keV, which can be changed by ground command. Since the experiment turn-on on 11 November 1990, it has recorded hard X-ray emission from ~100 solar flares of GOES soft X-ray class > M and several hundred …
The COS-B X-ray observations of X-ray binaries.
van der Klis, M.
The observational information on X-ray binaries that was collected with the 80 sq cm auxiliary X-ray detector onboard the COS-B gamma-ray satellite is reviewed. The results illustrate that in the study of X-ray binaries observations of long duration are extremely effective, even when using a small instrument.
Activity in late-type stars. IX. The weakest chromosphere M dwarf yet discovered : GL 105B.
Byrne, P. B.
We present an estimate of chromospheric radiative losses from the dM(e) star, Gl 105B, based on a measurement of the MgII h&k emission line flux, which indicates that this star has the weakest chromospheric heating rate yet found in any M dwarf and that it lies well below the 'basal' heating rate of derived by Schrijver (1987).
Radio emission from Jupiter observed by ULYSSES before and after encounter
Lecacheux, A.; Barrow, C. H.
The polarization and the occurrence probability of the radio emission from Jupiter at 940 and 52 kHz are compared before and after encounter. It is found that, after encounter, the right-hand polarized Main Component of the broad-band kilometric emission (bKOM) is not present while the left-hand polarized Intermittent Component is considerably enh…
Possible in situ detection of K2+ in the Jovian magnetosphere
McNutt, Ralph L., Jr.
During the Voyager 1 and 2 encounters with Jupiter in 1979 the positive ion composition of the cold thermal plasma in the Jovian plasma sheet and cold Io torus could be obtained when the plasma Mach number in the spacecraft rest frame was sufficiently large. Clear indication of an ionic species with a mass-to-charge ratio between 16 (O+…
A BBXRT Observation of the High-Luminosity Quasar H1821+643
Yaqoob, T.; Mushotzky, R. F.; Weaver, K. A. +3 more
We present the results of an observation of the high-luminosity quasar H1821+643 with the Broad-Band X-Ray Telescope (BBXRT) performed in 1990 December. The 2-10 keV flux and power-law spectral index are found to be consistent with previous values obtained by EXOSAT and Ginga which indicates that the medium-energy continuum has remained steady for…
Recent Results from the Hubble Space Telescope
Maran, Stephen P.; Kinney, Anne L.
A selection of recent findings from the Hubble Space Telescope (HST) are presented as a supplement to the earlier review by Kinney & Maran (1991). In stellar astrophysics, noteowrthy results include the first ultraviolet science from the High Speed Photometer, as well as spectroscopic studies of black hole and neutron star binaries and a flare…