Search Publications
Time and space variations of the Galactic cosmic ray electron spectrum in the 3-D heliosphere explored by Ulysses.
Sierks, H.; Kunow, H.; Wibberenz, G. +7 more
The Ulysses spacecraft, launched in Oct. 90 after solar maximum of solar cycle 22, has explored the heliographic latitudes above 70degS in summer 94, and has then made a rapid latitude scan down to the heliographic equator reached in March 95, in a period close to solar minimum. We present hereafter the Galactic electron spectra, with energies abo…
Analysis of Jovian Auroral H Ly-α Emission (1981-1991)
Ballester, Gilda E.; McGrath, Melissa A.; Clarke, John T. +1 more
We present a new analysis of jovian auroral IUE spectra covering the period from 1981 to 1991. To extract integrated auroral H Ly-α emission from these spectra we have developed a new extraction method that bins signal with wavelength while preserving the spatial information provided by the IUE imaging spectrograph. This separates auroral emission…
The Intermediate Stellar Mass Population in the M31 OB Association NGC 206
Lynds, Roger; O'Neil, Earl J., Jr.; Baum, William A. +1 more
As part of our effort to determine what affects the star formation process by looking at the products of that process, we have obtained broadband Hubble Space Telescope images of the large OB association NGC 206 in the nearby spiral galaxy M31. Our images cover approximately the southern half of the association. We have detected stars down to an F…
A search for hot post-AGB stars in the IRAS Point Source Catalog.
Oudmaijer, R. D.
In this paper a first step is made to search for hot post-AGB stars in the IRAS Point Source Catalog. In order to find objects that evolved off the AGB a longer time ago than post-AGB objects discussed in the literature, objects that were not detected at 12 µm by IRAS were selected, The selection yielded 15 objects, of which 12 have spectral…
Observations of a sky Lyman α groove related to enhanced solar wind mass flux in the neutral sheet
Bertaux, Jean-Loup; Lallement, Rosine; Quémerais, Eric
We report several observations of the Lα interplanetary emission recorded by a photometer flown in 1977 on board the soviet spacecraft Prognoz-5. The Prognoz scans sampled emission in a plane perpendicular to the sun-spacecraft line and also traversed the Lα maximum emission region (MER), a region centered a few AU from the Sun on the upstream int…
Ultraviolet Spectroscopy of the DBV White Dwarf Star GD 358
Provencal, J. L.; Shipman, H. L.; Thejll, P. +2 more
We report on analysis of UV spectra of the DBV GD 358 obtained with the Goddard High Resolution Spectrograph (GHRS) aboard the Hubble Space Telescope (HST). We confirm the detection of He II (1640 Å) and C II (1335 Å) reported by Sion et al. in 1988. The He II feature indicates a temperature of 27000±1000 K, somewhat higher than previous estimates…
The beta Pictoris Phenomenon in A-Shell Stars: Detection of Accreting Gas
Talavera, A.; England, M. N.; McCollum, B. +4 more
We present the results of an expanded survey of A-shell stars using IUE high-dispersion spectra and find accreting, circumstellar gas in the line of sight to nine stars, in addition to the previously identified beta Pic, HR 10, and 131 Tau, which can be followed to between +70 and 100 km s-1 relative to the star. Two of the program stars, HD 88195…
Goddard High Resolution Spectrograph Observations of Variability in the RS Canum Venaticorum System V711 Tauri (HR 1099)
Brown, Alexander; Neff, James E.; Linsky, Jeffrey L. +4 more
Goddard High Resolution Spectrograph (GHRS) observations of the RS CVn-type binary V711 Tau (K1 IV + G5 IV) were obtained at several phases over two consecutive stellar orbital cycles in order to study ultraviolet emission-line profile and flux variability. Spectra cover the Mg II h and k lines, C IV doublet, and Si IV region, as well as the densi…
The Evolution of Red Galaxies in Clusters T z=0.5
Hoessel, John G.; Gunn, James E.; Oke, J. B.
A program was carried out at Palomar Observatory to study seven clusters of galaxies all at redshifts near 0.5. Observations consisted of g, r, i, and z broadband Gunn photometry using 4-shooter, and ultraviolet u and violet v photometry using a CCD photometer at the prime focus of the Hale 5 m telescope. The u and v filters reach rest wavelengths…
Modelling of the Interstellar Hydrogen Distribution in the Heliosphere
Bzowski, M.; Ruciński, D.
The detailed knowledge of the distribution of neutral interstellar hydrogen in the interplanetary space is necessary for a reliable interpretation of optical and H+ pickup ions observations. In the paper, we review the status of the modelling efforts with the emphasis on recent improvements in that field. We discuss in particular the ro…