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Jovian electron jets in interplanetary space
Ferrando, P.; Raviart, A.; Ducros, R. +1 more
The COSPIN/KET experiment onboard Ulysses has been monitoring the flux of ∼ 3-20 MeV electrons in interplanetary space since the launch of Ulysses in October 1990. The origin of these electrons has been known for a long time to be the Jovian magnetosphere. Propagation models assuming interplanetary diffusion of these electrons in the ideal Parker …
Solar wind composition measurements by the Ulysses SWICS experiment during transient solar wind flows
Geiss, J.; Galvin, A. B.; Ipavich, F. M. +3 more
For the March/April 1991 time period, the alpha/proton abundance ratio, the proton kinetic temperature and speed distributions, and the relative abundance of O+7 to O+6 is determined over each 13-minute duty cycle of the Solar Wind Ion Composition Spectrometer (SWICS) experiment on Ulysses. The ratio (as a relative measure of ionization temperatur…
Colliding Wind Binary Systems: Monte Carlo Simulations of Line-Profile Variability
Stevens, Ian R.
We investigate the line-profile variability observed in colliding wind binary systems. In these systems the ultraviolet P Cygni line profiles show marked orbital variability; the nature of which differs between individual lines and binaries. We present results of three-dimensional Monte Carlo simulations of the radiative transfer and line formatio…
30 Doradus: Ultraviolet and Optical Stellar Photometry
Cheng, Kwang-Ping; O'Connell, Robert W.; Bohlin, Ralph C. +7 more
Stellar photometry is presented for 314 stars in a 9.7' x 9.7' field in the 30 Dor nebula centered on R136. Magnitudes are computed from Ultraviolet Imaging Telescope images in up to 4 bands with effective wave-lengths from 1615 to 2558 A, and from a ground-based CCD image in the B band. Spectral types and extinctions are estimated using a least- …
ROSAT/IUE discovery of a white dwarf companion to HD 33959C.
Barstow, M. A.; Hodgkin, S. T.; Pye, J. P. +2 more
We report the discovery, from the ROSAT EUV and X-ray all-sky surveys, and from IUE spectra, of a white dwarf (WD) companion to HD 33959C. RE 0515 + 324 is among the 10 brightest EUV sources in the sky in the 100-200 A band. It is also a strong soft X-ray source. IUE observations of candidate objects have revealed a previously uncataloged hot DA W…
Measurements of the interstellar gas
Lallement, R.
Two types of interstellar gas observations are considered; namely those made in the local interstellar medium on paths to nearby stars, and those obtained from the study of solar system gas. Optical measurements, and in particular Hubble Space Telescope spectra of the star Capella, have recently confirmed detection of the Local Interstellar Cloud …
Extremely Active Long-Period RS CVn Binary HD 12545
Fekel, Francis C.; Aufdenberg, Jason P.; Bopp, Bernard W. +2 more
The active-chromosphere giant HD 12545 is noteworthy for its remarkable 1990 photmetric amplitude of 0.6 mag in V, which implies that nearly half the visible hemisphere of the star was covered by cool spots. We report the results of a spectroscopic study of HD 12545, showing it to be an active-chromosphere binary with an orbital period of 23.97 da…
Indications for common origin and gravitational interaction in three binary LMC clusters.
Kontizas, M.; Kontizas, E.; Michalitsianos, A.
Three close pair clusters of the LMC, NGC 2006/SL 538, NGC 2011a/b and NGC 2042a/b, have been studied in order to establish their binarity. The stellar content in the outer region of each cluster has been investigated by means of low resolution objective UK Schmidt prism spectra, the cores of the clusters have been examined using low resolution in…
Determination of field distortion by a plate-overlap method.
Abad, C.
An automated reduction method for determining field distortion common to all plates based on a black-adjustment method proposed by Stock (1981) is demonstrated on the Paris Zone of the Astrographic Catalog. It is shown that the FK5 is suitable as the only reference source for zone catalogs.
The chemical compositions of Algol systems - V. Confirmation of carbon deficiencies in the primaries of eight systems.
Lambert, D. L.; Lemke, M.; Tomkin, J.
We use low-noise CCD spectra of 4267-Å C II line in the spectra of eight Algol-type eclipsing binaries to measure the C abundances of their primaries. A differential LTE analysis of the Algol binaries with respect to single standard stars of the same spectral type shows marginal to moderate deficiencies of C in the primaries of the binaries. We fi…