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New Perspectives on AX Monocerotis
Wilson, R. E.; Güdel, Manuel; Guinan, Edward F. +6 more
AX Moncerotis is a 232d, noneclipsing, interacting binary star that consists of a K giant, a Be-like giant, and large amounts of circumstellar material. The K star is almost certainly a synchronous rotator and is probably in contact with its critical lobe. The Be star was believed to be a rapid rotator based on extremely wide absorption…
Cosmic ray latitudinal effects predicted by a three-dimensional drift model
Potgieter, M. S.; Burger, R. A.; Hattingh, M. +1 more
The Ulysses spacecraft measured surprisingly small latitudinal gradients during its first passage through the polar regions of the heliosphere. This is in contrast to predictions made with two-dimensional drift models for A > 0 magnetic polarity epochs during solar minimum modulation conditions. Several modifications to drift models have been i…
Simultaneous Hubble Space Telescope and ASCA Observations of LMC X-4: X-Ray Ionization Effects on a Stellar Wind
McCray, R.; Cheng, F. H.; Boroson, B. +2 more
We present first results from simultaneous ultraviolet (HST/GHRS) and X-ray (ASCA) observations of the 13.5 s pulsar LMC X-4, taken in 1996 May. The ASCA observations covered 1.12 binary orbits (1.58 days), and the Hubble Space Telescope observations were centered on this for roughly 0.4 orbital phase coverage (0.56 days). The Goddard High Resolut…
The ultraviolet to X-ray spectrum of the Seyfert 1 galaxy E 1615+061: accretion disk and reflection models.
Piro, L.; Perola, G. C.; Fiore, F. +4 more
The Seyfert 1 galaxy E 1615+061 is a candidate for the strongest variability in soft X-rays, changing from a very steep high state ({GAMMA}=~4), as implied by HEAO1 observations performed in 1977, to a two orders of magnitude dimmer state with a flatter spectrum ({GAMMA}=~2), as observed by EXOSAT in 1985. In this paper we present the results of a…
The mass-loss history of the symbiotic nova RR Telescopii.
Nussbaumer, H.; Dumm, T.
Mass loss in symbiotic novae is of interest to the theory of nova-like events as well as to the question whether symbiotic novae could be precursors of type Ia supernovae. RR Tel began its outburst in 1944. It spent five years in an extended state with no mass-loss before slowly shrinking and increasing its effective temperature. This transition w…
An Investigation into Sulfur Isotopes in the Galactic Cosmic Rays
Thayer, M. R.
Measurements made by the Ulysses High Energy Telescope (HET) have made it possible for the first time to resolve the individual isotopes of sulfur 32S, 33S, and 34S. The measured ratio of Galactic cosmic-ray 34S/32S in the heliosphere is 24.2% +/- 2.7%. Based on this value, the Galactic source…
The Directivity of Solar Kilometric Type III Bursts: Ulysses-Artemis Observations in and Out of the Ecliptic Plane
Bougeret, J. -L.; Hoang, S.; Poquérusse, M.
Comparing the records of the radio spectrographs ARTEMIS (100-500 MHz) on the ground and URAP (1-1000 kHz) on the Ulysses spacecraft, we find that most type III bursts extend from the corona to the solar wind. Using the positions of the associated flares, and assuming an average intensity ratio between these two frequency ranges, we derive for the…
The discovery of UV oscillations in WZ SGE
Sion, Edward M.; Wood, Janet H.; Cheng, F. H. +2 more
We report the discovery of ~28-s ultraviolet oscillations in the cataclysmic variable WZ Sge. The strength of the oscillations is strongly wavelength-dependent: the oscillation amplitude decreases rapidly from lambda~1500 to ~1250 A. We interpret this decrease as an indication that the spectrum of the oscillations contains a broad Lyalpha absorpti…
The 1978-1995 variability of the symbiotic star AG Pegasi in the ultraviolet.
Altamore, A.; Cassatella, A.
In this paper we study in detail the variability of the symbiotic nova AG Peg in the IUE range during the period 1978-1995. We find that the luminosity of the hot component decreased steadily from about 1850Lsun_ in 1978 to 430Lsun_ in 1995 while its effective temperature remained nearly constant, 86500+/-1300K. At the same t…
Luminosity and related parameters of δ Scuti stars from HIPPARCOS parallaxes. General properties of luminosity.
Mantegazza, L.; Antonello, E.
The absolute magnitudes of δ Scuti stars derived from parallaxes measured by the Hipparcos astrometric satellite are discussed and compared with the previous estimates based on photometric uvbyβ indices. There are significant differences which are related to photometric effects of metallicity and rotational velocity, but the possible effect of a c…