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The nature of visual components in 82 multiple systems

Shatskii, N. I.

We performed photoelectric BVR observations of 198 visual components in 82 multiple systems. We used a special technique for the measurements with a classical photometer. In our study of close visual binaries, we employed a new instrument - an astrometric scanning photometer; its design is described. Based on our photometric data in combination wi…

ISOPHOT Mapping Observations of a Mira-Type AGB Star R Hya

Izumiura, H.; Hashimoto, O.

Far-infrared mapping observations of a Mira-type AGB star R Hya were carried out with the imaging photo-polarimeter ISOPHOT.

Dust Formation and Mass Loss in Evolved Stars

Winters, Jan Martin

The problem of dust formation in the circumstellar envelopes of Asymptotic Giant Branch stars is addressed. We summarize the basic thermodynamic prerequisites necessary to enable the formation and growth of solid particles from the gas phase and draw some conclusions on the evolution of the emergent dust component. In a circumstellar environment t…

HST observations of middle aged isolated neutron stars

Caraveo, P. A.; Bignami, G. F.; Mignani, R.

We report the results of recent HST observations of three Middle Aged Isolated Neutron Stars i.e. PSR1055-52, Geminga and PSR0656+14. For PSR1055-52, a probable optical counterpart has been identified with the FOC. For PSR0656+14, WFPC2 imaging provided a clear detection of the proposed optical counterpart and was used to obtain a tentative measur…

Model Atmospheres of AGB Stars: Dynamics, Molecules and Dust

Loidl, Rita; Höfner, Susanne; Jφrgensen, Uffe G.

The atmospheres and circumstellar envelopes of AGB stars are characterized by complex physical phenomena like shock waves caused by stellar pulsation or formation of molecules and dust which often lead to a heavy mass loss and have a strong influence on IR properties as observed by ISO. To allow a physical interpretation of various observations we…

Solar Radiometry with the Telescope and Vaccum-Ultraviolet Spectrometer Sumer on the Solar and Heliospheric Observatory (SOHO)

Curdt, W.; Dammasch, I. E.; Hollandt, J. +3 more

UV Rejection Design and Performance of the PEACE Electrostatic Analyzers

Alsop, C.; Scott, S.; Free, L.

The Plasma Electron and Current Experiment, PEACE, electrostatic analyzers are designed to measure electrons from 0.6 eV to 26,400 eV and will be directly exposed to sunlight in their operational environment. To minimize solar background counts, generated by direct interaction of the solar UV with the microchannel plate detectors or by the generat…

Are low-order resonances observed in Mira pulsation?

Barthes, D.; Mennessier, M. O.; Vidal, J. L. +1 more

The possibility of a low-order, two-mode resonance in the pulsation of LPVs is investigated by means of Fourier analysis of lightcurves, supplemented by spectral types and by kinematic population analysis based on HIPPARCOS astrometric data. The question might be positively answered. Based on data from the HIPPARCOS astrometry satellite.

Duplicity in Hubble Space Telescope Guide Stars: Fine Guidance Sensor Serendipitous Survey Results

Schneider, Glenn; Hershey, John L.; Wenz, Michael T.

Data from the Hubble Space Telescope (HST) Fine Guidance Sensor (FGS) interferometers, covering 22 months of guide-star acquisition operations, have been analyzed for evidence of stellar duplicity. The data comprise a survey of observed guide stars, all of which are taken from the HST Guide Star Catalog, ranging in magnitude from 9 to 14. The surv…

Molecules in Stellar Atmospheres

Gustafsson, B.

The effects of molecules on model stellar atmospheres are briefly reviewed. Molecular diagnostics of stellar fundamental parameters and of atmospheric structure are discussed, and the presently emerging "ISO picture" of the outer regions of stars is commented upon.