Search Publications
Missions
Journals
Publication Years
A survey of vacuum-ultraviolet extinction curves based on International Ultraviolet Explorer spectra
Patriarchi, P.; Megier, A.; Aiello, S. +1 more
This paper presents the interstellar extinction curves derived from the International Ultraviolet Explorer (IUE) spectra with the aid of the already published `artificial standards'. The variety of possible shapes of the curves, demonstrated earlier on spectra from the TD/1 satellite, is fully confirmed.
Ulysses observations of short-period (≤30 Days) modulation of the galactic cosmic rays
Keppler, E.; Kunow, H.; Heber, B. +3 more
A frequency analysis of the short-period modulation of the GCR as seen by instruments aboard Ulysses shows interesting temporal variations. In particular, during an approximate five-month period from December 1993 to May 1994, the modulation was not the usual 26 days but more than 29 days. The CIR-associated MeV ions did not exhibit this period sh…
The heliospheric magnetic field at solar minimum as observed by ULYSSES
Balogh, A.; Horbury, T. S.; Smith, E. J. +1 more
Since February 1992 the Ulysses spacecraft has been in a polar orbit round the Sun, reaching 80 deg heliolatitude over the south pole in September 1994 and over the north pole in July 1995. During this time solar activity has been gradually declining towards its present minimum in mid-1996. We discuss how the large scale configuration of the helio…
The Latitudinal Structure of the Solar Wind in the Vicinity of the Solar Equator near Solar Minimum: 1986 and Predictions for 1997
Gazis, P. R.
In situ observations by different spacecraft have shown that the heliospheric current sheet (HCS) is associated with a narrow band of low speed high density solar wind. The inclination of the HCS and the three-dimensional structure of solar wind streams is related to the inclination of the coronal neutral line. Observations from the Ulysses spacec…
First Observations of Coronal Hole Structure and Evolution Using Soho-Cds
Harrison, R. A.; Moore, V.; Insley, J. E.
We report on initial observations of coronal holestructure and evolution by the Coronal Diagnostic Spectrometer (CDS) instrument on board the Solar and Heliospheric Observatory (SOHO). The data show that there is coronal activity on time scales of tens of minutes, manifested as brightenings at chromospheric network cell junctions in extreme ultrav…
Ultraviolet Color-Magnitude Diagram Studies of Intermediate Age Large Magellanic Cloud Star Clusters.I.NGC 1783
Cole, Andrew A.; Freedman, Wendy L.; Gallagher, John S., III +1 more
We have imaged the billion-year-old Large Magellanic Cloud star cluster NGC 1783 with the Wide Field/Planetary Camera 2 (WFPC2) in order to obtain broadband photometry at 1600 and 3300 Angstroms. We have identified for the first time the individual stars responsible for the unexpectedly strong ultraviolet light of intermediate-age stellar systems.…
Parallaxes and Proper Motions of Prototypes of Astrophysically Interesting Classes of Stars. I. R Coronae Borealis Variables
Kundu, Arunav; Trimble, V.
Hipparcos data were obtained under the 1982 announcement of opportunity for the seven brightest R CrB stars then known. None of the parallax measurements is different from zero in a statistically significant way, though most of the proper motions are. The body of the data nevertheless suggest that the stars belong to two rather different populatio…
Ulysses observations of energetic H3+ ions in Jupiter's magnetosphere
Krupp, N.; Woch, J.; Keppler, E. +3 more
Ulysses was the fifth spacecraft to visit Jupiter. In this paper measurements of energetic H_3^+-ions in the Jovian magnetosphere made by the EPAC (Energetic Particle Composition) instrument onboard Ulysses are presented and compared with formerly published findings from the HI-SCALE instrument also onboard Ulysses.
Probing Galactic Center Black Hole Candidates with Far-Infrared Spectroscopy
Hollenbach, David J.; Colgan, Sean W. J.; Maloney, Philip R.
The narrow positron annihilation line source in the Galactic center has been identified with the X-ray source 1E 1740.7-2942, which is coincident in projection with a Galactic center molecular cloud and exhibits synchrotron jets in the radio spectrum. It has been suggested that the source is powered by Bondi-Hoyle accretion from the cloud onto a c…
Anomalous Cosmic-Ray Helium, Nitrogen and Oxygen in 1996 - Measurements of the ERNE Instrument on-board SOHO
Vainio, R.; Valtonen, E.; Riihonen, E. +4 more
The energy spectra of the anomalous components of helium, nitrogen and oxygen have been measured by the ERNE experiment on board the SOHO spacecraft. During February 28-April 30, 1996, the maximum intensity of anomalous helium was found to be 3.8 × 10-5 cm-2 sr-1 s-1 (MeV nucl-1)-1 …