Search Publications
Hubble Deep Field guide star photometry
Zwintz, K.; Kuschnig, R.; Weiss, W. W. +2 more
Since the advent of asteroseismology as a promising innovative tool for investigating internal stellar structure, numerous attempts to detect solar type oscillations in distant stars have been conducted. The three Fine Guidance Sensors of the Hubble Space Telescope can contribute to asteroseismology, but only after the data have been corrected for…
The Eclipsing Cataclysmic Variable V347 Puppis Revisited
Hubeny, Ivan; Diaz, Marcos P.
An observational study of the nova-like cataclysmic binary V347 Pup (LB 1800) is presented. An analysis of optical and UV spectroscopy is made with the aim of defining the physical properties of the binary system and of the accretion disk. The study of the line profile behavior and the determination of the primary radial velocity are pursued using…
On the gradients of ACR oxygen at intermediate heliocentric distances: Ulysses/Soho results
Torsti, J.; Sanderson, T. R.; Marsden, R. G. +3 more
During 1997 and up to the present time, the heliocentric position of the Ulysses spacecraft has changed only slowly in distance and latitude, being close to the equator at a distance of ~5 AU. This period provides an excellent opportunity to observe the evolution of the Anomalous Cosmic Ray (ACR) spectrum at a location intermediate between 1 AU an…
The density-wave nature of the Cygnus-Orion arm
Sitnik, T. G.; Mel'Nik, A. M.
Radial velocities and Hipparcos proper motions are used to construct the residual space velocity field for the OB associations in the Cygnus-Orion arm. We detected systematic motions typical of density-wave arms in Cyg OB1, OB3, OB7, OB8, OB9, Sco OB2, Cep OB2 and OB3 and those typical of the interarm space within the corotation radius in Per OB2,…
Serendipitous Discovery of a Cataclysmic Variable in the Globular Cluster NGC 6624
Anderson, Scott F.; Margon, Bruce; Deutsch, Eric W. +1 more
Despite indications that classical cataclysmic variable (CV) stars are rare in globular clusters in general, and in the cluster NGC 6624 in particular, we have serendipitously discovered such a star ~6" from the cluster center. A Hubble Space Telescope spectrum of the m~22 object shows strong, broad emission lines typical of numerous field CVs, an…
High Energetic Electrons Accelerated by a Coronal Shock Wave
Mann, G.; Kunow, H.; Motschmann, U. +2 more
Combined SOHO (Solar and Helisopheric Observatory) and ground based radio observations show evidently signatures of electrons accelerated by a shock wave during the event on July 9, 1996. A solar type II radio burst has been received as a signature of a coronal shock wave at 300 MHz on 9:10:54 UT. It was accompanied with electron beams appearing a…
The eclipse of the symbiotic star SY MUSCAE
Pereira, C. B.; Ortega, V. G.; Monte-Lima, I.
We present ultra-violet observations of the symbiotic star SY Mus obtained with IUE in 1996. The observations were timed to cover ingress and egress. We observe phase dependent intensity variations of the continuum and of the emission lines. These variations are caused by a wavelength dependent opacity with the characteristics of Rayleigh scatteri…
New observations of 53 Persei
De Ridder, J.; Aerts, C.; Gordon, K. D. +1 more
We gathered 37 new spectra of the B star 53 Persei spread over approximately 2 years. On these data, we performed a frequency and a mode analysis. We determined the physical parameters of 53 Persei and placed the star in the theoretical SPB instability strip. We also analysed the 110 photometric observations of the Hipparcos satellite. Our results…
Clustering Properties of Low-Redshift QSO Absorption Systems Toward the Galactic Poles
York, Donald G.; Blades, J. Chris; Lauroesch, James T. +8 more
NO>1Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.
Coronal magnetic field topology and source of fast solar wind
McComas, D.; Guhathakurta, M.; Thompson, B. +2 more
We have developed a steady state, 2D semi-empirical MHD model of the solar corona and the solar wind with many surprising results. This model for the first time shows, that the boundary between the fast and the slow solar wind as observed by Ulysses beyond 1 AU, is established in the low corona. The fastest wind observed by Ulysses (680-780 km/s) …