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Some recent results for the roAp stars

Kurtz, D. W.

Three topics are discussed: 1) Photometric observations of the rapidly oscillating Ap stars have shown that the pulsation amplitude drops dramatically as a function of wavelength from the blue to the red. A theoretical derivation, plus modelling, indicates that this is because the vertical wavelength of the pulsation mode is short compared to the …

Spectroscopy and Spectral Energy Distribution of the Peculiar Supergiant IRAS 04296+3429

Szczerba, R.; Klochkova, V. G.; Panchuk, V. E.

An IUE Spectroscopic Study of the Ultra-Short-Period Dwarf Nova T Leonis in Outburst

Sion, E. M.; Huang, M.; Fabian, D. +2 more

The IUE archive contains numerous low-resolution spectra of dwarf novae in outburst but relatively little synthetic spectral analyses of them using realistic accretion disk models with spectral lines. We have examined a series of previously unstudied archival IUE low-resolution short-wavelength prime spectra of the SU UMa-type ultra-short-period d…

Omega, Age, and H_0 Implications of Recent Hubble Space Telescope Data in the Coma Cluster

Baum, William A.

This paper presents a way of finding mutually consistent values of Omega_M, t_0, and H_0. This approach is illustrated using recent Coma Cluster distance data, together with recent Hipparcos data for RR Lyrae stars. The age of the universe is derived by two completely independent methods, both linked to the RR Lyrae stars. The two methods can be m…

The Imaging Neutral Camera for the Cassini Mission to Saturn and Titan

Krimigis, S. M.; Mitchell, D. G.; Roelof, E. C. +8 more

The INCA sensor is the first Energetic Neutral Atom (ENA) imager funded for flight by NASA. It is a part of the Cassini mission to Saturn, where it will be well suited to monitoring the global dynamics of the Saturn-Titan magnetospheric system throughout the orbital tour. The investigative requirement is to perform remote sensing of the magnetosph…

Age variation of helium abundance in He-rich stars.

Glagolevskij, Yu. V.

Investigations of the He abundance variation depending on the age of He-rich stars have been continued. A comparison of the Hipparcos satellite absolute magnitudes and lg g with data obtained previously from the β parameters of multicolour photometry has shown good agreement (Gomez et al., 1998). A critical revision of all previous data, using the…

ISO Observations of Symbiotic Stars

Clavel, J.; Metcalfe, L.; Schulz, B. +8 more

A number of symbiotic stars have been observed with ISO. In addition to a number of emission lines, SWS observations of the symbiotic novae RR Tel and V1016 Cyg reveal prominent, broad 10 & 18 µm silicate dust features. The 10 µm features are similar to the crystalline silicate profiles seen in classical novae. There is some evidence that the …

Chemical Abundances of Planetary Nebulae: A UV to Far-IR Case Study of NGC 6153

Liu, X. -W.

The evolutionary state and fundamental parameters of metallic A-F giants

North, P.; Kunzli, M.; Erspamer, D.

Using Hipparcos parallaxes, we show that the metallic A-F giants found by Hauck on the basis of their high Delta m(2) index in Geneva photometry are on average more evolved than their non-metallic counterparts. Their mass distribution, rate of binaries and v sin i are shown to be incompatible with those of Am stars, so that they cannot be descenda…

First Results from ISO Spectra of Supernova Remnants Heavily Interacting with the ISM

Lutz, D.; Sturm, E.; Oliva, E. +2 more

ISO spectra of the supernova remnant RCW103 are presented. This object is the prototype of a SNR shock heavily interacting with dense ISM (probably a molecular cloud). The spectra are dominated by prominent lines and show very little continuum at λ < 40 µm suggesting that the 12 and 25 µm IRAS emission from these types of remnant could be domin…