Search Publications
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…
Intense molecular emission from the Lagoon nebula, M8.
White, G. J.; McCaughrean, M. J.; Tothill, N. F. H. +3 more
The discovery is reported of the second strongest source of mm and submm wavelength CO line emission, towards M8, the Lagoon Nebula in Sagittarius. The ~31Msun_ molecular core has dimensions ~0.2x0.3pc and is centred on the O7V star Herschel 36 (H36), near the Hourglass Nebula in the core of M8. Emission from the CO line wings extends t…
Trapped energetic ions in Jupiter's inner magnetosphere
Anglin, J. D.; Burrows, J. R.; Mu, J. L. +1 more
Ion measurements made with the high-flux telescope at ~1MeV/nucleon during the passage of the Ulysses spacecraft through Jupiter's inner magnetosphere are presented. Stable pancake-shaped pitch angle distributions were observed for protons inside ~17RJ. They are fitted by a time-independent model in which an assumed directional flux at …
An Unusual Brightening of the Eclipsing Binary Star AKO 9 in the Globular Cluster 47 Tucanae Observed with the Hubble Space Telescope
Minniti, Dante; Pryor, Carlton; Tinney, Christopher G. +3 more
Fifteen sequential images of the core of the globular cluster 47 Tucanae taken in ultraviolet light with the Hubble Space Telescope have revealed one star that increased in brightness by more than 2 mag in less than an hour. By the end of our observations, this star was the brightest object in the core of the cluster in our bandpass. Aurière et al…
The barium stars in the Hertzsprung-Russel diagram.
Bergeat, J.; Knapik, A.
We present absolute magnitudes for a sample of 52 barium stars observed by the HIPPARCOS satellite, and their location in the HR diagram. Our plot (Fig. 1) is restricted to stars with parallax accuracies better than 22%. The luminosity classes range from Ib supergiants down to V dwarfs on the main sequence, as expected from spectral classificaiton…
Three-Dimensional Orbits of Metal-poor Halo Stars and the Formation of the Galaxy
Yoshii, Yuzuru; Chiba, Masashi
We present the three-dimensional orbital motions of metal-poor stars in conjunction with their metal abundances, for the purpose of getting insight into the formation process of the Galaxy. Our sample stars, which include metal-deficient red giants and RR Lyrae variables observed by the HIPPARCOS satellite, are least affected by known systematics,…