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Optical, IUE, and ROSAT Observations of the Eclipsing Nova-like Variable V347 Puppis (LB 1800)
Raymond, John C.; Buckley, David A. H.; Mauche, Christopher W. +5 more
Using time-resolved optical spectroscopy and UBVRI and high-speed photometry obtained at Mount Stromlo Observatory, Mount John University Observatory, and the South African Astronomical Observatory; International Ultraviolet Explorer (IUE) ultraviolet spectroscopy; and Roentgen Satellite (ROSAT) survey X-ray fluxes, we present a study of the accre…
Interstellar and Intergalactic Magnesium and Sodium Absorption toward SN 1993J
Bowen, David V.; Meyer, David M.; Roth, Katherine C. +1 more
We present echelle-resolution (FWHM ~ 5 km s^-1^) HST observations of Mg II, Mg I, and ground-based observations of Na I absorption toward SN 1993J which exploded in M81. We detect individual absorption components spanning a total velocity range of -163 < ν_sun_ < +225 km s^-1^. The components are grouped into three subcomplexes, representin…
GHRS Spectroscopy of Individual Stars in R136a
Hubeny, Ivan; Heap, Sara R.; Malumuth, Eliot M. +3 more
The installation of the Corrective Optics Space Telescope Axial Replacement (COSTAR) Instrument on the Hubble Space Telescope (HST) makes it possible to observe stars in very crowded regions with high spatial and spectral purity. To demonstrate this capability, we have used the Goddard High Resolution Spectrograph (GHRS) to obtain spectra of two s…
ROSAT Observations of Cataclysmic Variables: A Search for the Boundary Layer Emission
Raymond, J. C.; Vrtilek, S. D.; Patterson, J. +1 more
Many cataclysmic variables (CVs) and low-mass X-ray binaries show He II line emission at wavelength 1640 and wavelength 4686. As recombination lines of an ion requiring 55 eV for ionization, these lines cannot be attributed to gravitational heating in the disk but could be due to reprocessed 55-280 eV X-rays which may be produced in a boundary lay…
Classical Cepheids with Terminal Age Main-Sequence Companions: Constraints on Evolution
Evans, Nancy Remage
Eight binaries containing a Cepheid and a hot companion evolved beyond the ZAMS are studied using IUE spectra. The spectral types of these TAMS (terminal age main-sequence) companions are determined from the spectra and absolute magnitudes are determined from the magnitude difference between the two stars and the absolute magnitude of the Cepheid.…
A Thermal Pulse in Progress in the Nucleus of the Large Magellanic Cloud Planetary Nebula N66
Pena, M.; Torres-Peimbert, S.; Ruiz, M. T. +2 more
Optical and UV spectrophotometric data, gathered in the 1987-1994 interval, are presented for the planetary nebula N66 (WS 35 or SMP 83) in the Large Magellanic Cloud. These data show that the central star has suffered dramatic changes. Before 1987 it showed a featureless continuum while its present spectrum shows intense W-R features and P-Cygni …
A Spectrum Synthesis Program for Binary Stars
Linnell, Albert P.; Hubeny, Ivan
A new program produces synthetic spectra of binary stars at arbitrary values of orbital longitude, including longitudes of partial or complete eclipse. The stellar components may be distorted, either tidally or rotationally, or both. Either or both components may be rotating nonsynchronously. We illustrate the program performance with two cases: E…
The X-Ray Selected Cataclysmic Variables H0459+246 and H0857-242
Buckley, D. A. H.; Schwartz, D. A.; Tuohy, I. R. +5 more
We report the discovery of two cataclysmic variables located with the assistance of X-ray positions from the HEAO 1 Modulation Collimator and the Large-Area Sky Survey. Each case is distinguished by evidence of two periodic modulations that appear to represent the orbital period and the spin period of the white dwarf, respectively. The first case,…
Spectroscopy of Chromospheric Lines of Giants in the Globular Cluster NGC 6752
Smith, Graeme H.; Dupree, A. K.; Hartmann, Lee +3 more
Spectroscopic observations of chromospheric transitions (Mg II, H-alpha, and Ca II K) from two red giants (A31 and A59) in the globular cluster NGC 6572 were made with the Goddard High Resolution Spectrograph on the Hubble Space Telescope and the coude spectrograph of the 1.9 m telescope at the Mount Stromlo Observatory. These measurements give ev…
Stellar Photometry Including Saturated Images: Results on M67 with WFPC2
Gilliland, Ronald L.
The Wide Field and Planetary Camera 2 (WFPC2) on Hubble Space Telescope (HST) is providing unsurpassed imaging capabilities and supporting accurate stellar photometry over large fields of view at high angular resolution. I discuss a feature of the WFPC2 CCD systems that nominally limits the dynamic range attainable with single exposures: a 12 bit …