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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.
Is the Galactic Halo Planetary Nebula PN G243-37.1 an ``O VI Sequence'' Variable Object?
Feibelman, Walter A.
Archival IUE spectra of the Galactic halo planetary nebula PN G243-37.1 have been reprocessed by the NEWSIPS routine. The new results show a much richer emission-line spectrum than has previously been reported. Several C iii, C iv, O v, and possibly O vi features were detected. P Cygni line profiles could not be identified with certainty. The He i…
Spectroscopy of the Cataclysmic Variable UU Aquarii: s-Waves and Bright Spots
Schlegel, Eric M.; Kaitchuck, Ronald H.; White, James C., II +1 more
This paper reports the results of UV and optical spectroscopy of the nova-like variable UU Aqr. There is a decrease in the light flux of both the optical and UV emission lines at phase ~0.95. This appears to be due to an occultation of an asymmetric accretion disk. The emission-line profiles seem to show the first half of the rotational disturbanc…
Analysis of the waves associated with the unusual interplanetary shock observed on day 109, 1992
Balogh, A.; Lucek, E. A.
On day 109 of 1992 Ulysses observed an extraordinary interplanetary shock at a time of extremely unusual interplanetary magnetic field conditions. The field was closely aligned with the radial direction for nearly a day ahead of the shock, suggesting that it was most likely to be a quasi-parallel shock. Unlike most interplanetary shocks, this shoc…
High-Excitation Emission Lines in the Far-Ultraviolet Spectrum of the Late A Star α Cephei
Ayres, Thomas R.; Simon, Theodore
The A7 V star α Cephei lies in a region of the Hertzsprung-Russell diagram that is generally thought to be devoid of solar-like magnetic activity. The far-ultraviolet spectrum of this star was observed with the Berkeley spectrograph during the 1996 ORFEUS-SPAS II mission. We detected emission lines of Si III, C III, and O VI in the 900-1200 Å inte…
Reprocessed UV pulses from the binary companions of X-ray pulsars
Dolan, J. F.; Boyd, P. T.; Percival, J. W. +3 more
A search for reprocessed X-rays causing UV pulsations in the companion stars to X-ray pulsars was carried out in a 200 Angstroms wide bandpass centered at 1450 Angstroms using the High Speed Photometer on the Hubble Space Telescope. We observed the systems A0535+26 = HD245770, 4U0900-40 (Vela XR-1) = HD77581, A1118-61 = He3-640, and 4U1145-619 = H…
Mid-infrared spectroscopy of obscured IRAS galaxies
Taniguchi, Yoshiaki; Sato, Yasunori; Kawara, Kimiaki +1 more
Spectra from 6 to 12 mu m are presented for the infrared galaxies NGC 1266, Arp 148, and IRAS 1713+53. Though they are not markedly luminous (<= 10(12) L_⊙), their IRAS colors are close to the colors of ultraluminous infrared galaxies, and thus indicative of heavy obscuration. The 6-12 mu m spectra are dominated by emission features of polycycl…