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The Detection of Photospheric X-Ray Pulsations from PG 1159-035 with EXOSAT
Winget, D. E.; Barstow, M. A.; Holberg, J. B. +1 more
The detection of soft X-ray pulsations from the hot, helium-rich, degenerate object, PG 1159-035 is reported. These observations, obtained with the Low Energy experiment on EXOSAT, show the presence of large-amplitude soft X-ray (44-150 A) pulsations analogous to several of the low-amplitude, nonradial, g-mode pulsations which are observed in the …
Ultraviolet Spectrophotometry of Three LINERs
Keel, W. C.; Goodrich, R. W.
Three galaxies known to be LINERs were observed spectroscopically in the ultraviolet in an attempt to detect the presumed nonthermal continuum source thought to be the source of photoionization in the nuclei. NGC 4501 was found to be too faint for study with the IUE spectrographs, while NGC 5005 had an extended ultraviolet light profile. Compariso…
Ultraviolet Observations of V471 Tauri: Evidence for a Nova-like Outburst?
Bruhweiler, F. C.; Sion, E. M.
A search for accretion of wind-flare material onto the white dwarf in V471 Tauri has unexpected by revealed what appears to be shortward-shifted absorption, centered on two distinct velocities, near heliocentric velocities of -300 and -590 km/s in the line of sight toward V471 Tauri. The possibility that these features are due to instrumental effe…
The Strong UV Source in the Active E Galaxy NGC 4552
Thuan, T. X.; Puschell, J. J.; Oconnell, R. W.
1200-3200 A IUE spectra of the nucleus of NGC 4552 (M89) were obtained in order to investigate the nature of the strong 10 micron source in this Galaxy. There is a strong, extended UV source in NGC 4552 which has a spatial distribution nearly identical with that at optical wavelengths and is undoubedly stellar in origin. Its properties are consist…
Far-Ultraviolet Fluorescence of Carbon Monoxide in the Red Giant Arcturus. II. Analysis of High-Dispersion IUE Spectra
Ayres, T. R.
Faint, diffuse emissions near 1380 A in deeply exposed IUE spectrograms of the red giant Arcturus very likely are associated with bands of the A-X fourth-positive system of carbon monoxide, fluoresced by multiplet UV2 of neutral oxygen near 1305 A. Numerical simulations indicate that the strength of the CO bands is exceedingly sensitive, in the be…
X-ray spectrum of the 2A 0335+096 cluster of galaxies.
Singh, K. P.; Westergaard, N. J.; Schnopper, H. W.
The paper presents the X-ray spectrum of a poor cluster of galaxies 2A 0335 + 096 obtained with the medium energy and the gas scintillation proportional counter experiments on board Exosat. The observed spectrum is best explained by a thermal bremsstrahlung emission process from a hot intracluster gas with a temperature of about 3.4 x 10 to the 7t…
The Cepheid Mass Problem and Cepheid Binaries
Bohm-Vitense, E.
Existing mass determinations for Cepheids with different periods are examined. Wesselink masses are independent of the adopted distance scale. For short periods (less than 6 days) they follow the sequence of evolutionary masses. For periods longer than 10 days they are lower by up to a factor of 2. The lower mass branch joins up with the bump mass…
Ultraviolet, Optical, Infrared, and Microwave Observations of HR 5110
Linsky, J. L.; Simon, Theodore; Ayres, T. R. +5 more
HR 5110 is a close binary system (P = 2d.6) with the characteristics of an Algol system. Because the primary star is relatively cool (F2 IV) and there is no apparent emission from an accretion disk, the authors were able to detect in IUE spectra the emission of an active chromosphere and transition region of the cooler (K0 IV) secondary…
Spectrum and Chemical Analysis of the Double-Ring Planetary Nebula IC 1297
Feibelman, Walter A.; Aller, Lawrence H.; Keyes, Charles D.
The double-ring planetary nebula IC 1297 resembles NGC 7662 in appearance, although it is of much lower surface brightness. What is remarkable is the great strength of the dielectronic recombination O V line. Although this line is seen as a P Cygni feature in a number of planetary nebulae, it is in those instances accompanied by a strong continuum…
New X-Ray and Optical Observations of the X-Ray Discovered QSO-Galaxy Pair 1E 0104.2+3153
Stocke, J. T.; Giommi, P.; Maccacaro, T. +2 more
New X-ray and optical observations are presented of the QSO-galaxy pair 1E 0104.2 + 3153, originally discovered as a serendipitous source in the Einstein Observatory Medium Sensitivity Survey (Gioia et al., 1984). Results from an extremely deep Exosat observation are used to suggest that the QSO rather than the compact group of galaxies is the opt…