Search Publications
An X-Ray Excited Wind in Centaurus X-3
Stevens, Ian R.; Day, C. S. R.
We propose a new interpretation of the behavior of the notable X-ray binary source Centaurus X-3. Based on both theoretical and observational arguments (using EXOSAT data), we suggest that an X-ray excited wind emanating from the O star is present in this system. Further, we suggest that this wind is responsible for the mass transfer in the system…
An Occultation by Saturn's Rings on 1991 October 2-3 Observed With The Hubble Space Telescope
Bosh, A. S.; Dolan, J. F.; Nelson, M. J. +7 more
An occultation of the star GSC 6323-01396 (V = 11.9) by Saturn's rings was observed with the High-Speed Photometer on the Hubble Space Telescope (HST) on 1991 October 2-3. This occultation occurred when Saturn was near a stationary point, so the apparent motion of Saturn relative to the star was dominated by the HST orbital motion (8 km/s). Data w…
Variable C IV Absorption in the Seyfert Galaxy NGC 5548: A Connection to Broad Absorption Line Quasi-stellar Objects?
Shull, J. Michael; Sachs, Elise R.
This is the second in a series of papers examining variable absorption components in the broad emission lines of Seyfert 1 galaxies. In an IUE survey of a complete sample of CfA Seyfert galaxies, we find that at least 12% and perhaps as many as 27% of the objects show evidence of intrinsic absorption in C IV 1549. In this paper, we use data from a…
The beta Pictoris circumstellar disk. XV. Highly ionized species near beta Pictoris.
Deleuil, M.; Feldman, P. D.; Moos, H. W. +7 more
Temporal variations of the Fe II, Mg II, and Al III circumstellar lines towards Beta Pictoris have been detected and monitored since 1985. However, the unusual presence of Al III ions is still puzzling, since the UV stellar flux from an A5V star such as Beta Pic is insufficient to produce such an ion. In order to better define the origin of such a…
The Boron Abundance of Procyon
Lambert, David L.; Edvardsson, Bengt; Lemke, Michael
The B I 2496.8 A resonance line and HST/GHRS echelle spectra are used with model atmospheres and synthetic spectra to derive the B abundance of the F dwarfs Procyon (alpha CMi), Theta UMa, and Iota Peg. The B abundance (log epsilon(B)~/=2.3) of Theta UMa and Iota Peg is similar to that derived by Boesgaard and Heacox from the B II resonance line i…
Hubble Space Telescope Imaging of Herbig-Haro Object No. 2
Schultz, A. S. B.; Raymond, John C.; Dopita, Michael A. +6 more
Images of Herbig-Haro Object No. 2 obtained with the Planetary Camera of the Hubble Space Telescope are presented and discussed. The images, obtained in the emission lines of H-alpha, forbidden S II, and forbidden O III at a scale of 0.044 arcsec/pixel, have been registered to within 11 milliarcsec, and the spherically aberrated images have been r…
Source characteristics of Jovian hectometric radio emissions
Stone, R. G.; Fainberg, J.; Reiner, M. J.
Direct confirmation that low-frequency Jovian hectometric (HOM) radio emissions centered near 0° central meridian longitude consist of distinct, oppositely polarized northern and southern beams has been achieved using data from the Unified Radio and Plasma Wave (URAP) experiment on the Ulysses spacecraft during the Ulysses-Jupiter encounter in ear…
Field-aligned currents in the Jovian magnetosphere during the Ulysses flyby
Dougherty, M. K.; Balogh, A.; Smith, E. J. +1 more
The data recorded by the dual vector helium/ fluxgate magnetometer flown onboard the Ulysses spacecraft during the flyby of Jupiter in February 1992 are analysed with the aim of identifying the presence of field-aligned current signatures. Field-aligned current flow is expected wherever stress is being transmitted electromagnetically along the mag…
A far UV investigation of luminous hot stars in the SMC cluster NGC 330.
Caloi, V.; Castellani, V.; Cassatella, A. +1 more
IUE observations of luminous blue stars in the SMC young cluster NGC 330 have been used to determine the reddening and the effective temperatures of the program objects. The reddening is estimated to be E(B - V) = 0.09 +/- 0.02, intermediate between old (~0.02) and recent (~0.12) evaluations. Stars with no recognized atmospheric anomaly show a goo…
Jovian electron propagation in three dimensions of the heliosphere: The Ulysses investigations
Balogh, A.; Smith, D. A.; Simpson, J. A. +1 more
We report investigations of Jovian relativistic electrons in the interplanetary medium that provide new insights into both the physical processes by which the Jovian magnetosphere releases its trapped relativistic electrons into the interplanetary medium, and the modes of their interplanetary propagation. These studies were dependent on the unique…