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SAO 244567 : a post-AGB star which has turned into a planetarey nebula within the last 40 years.
Pottasch, S. R.; Clavel, J.; de Martino, D. +5 more
SAO 244567 (Hen 1357 = CPD -59 deg 6926 = IRAS 17119-5926) is an IRAS source with far infrared colors and flux distribution similar to those of planetary nebulae. The IUE ultraviolet spectra obtained in July 1988 and April 1992 show nebular emission lines, and also the changes in the spectra suggest the formation of the planetary nebula and the ra…
Lyman-alpha emission in spectra of Herbig AE stars. an indication of accretion ?
Talavera, A.; Blondel, P. F. C.; Djie, H. R. E. T. A.
Lyman-alpha emission lines have been detected in the IUE spectra of several Herbig Ae stars, but not in those of Herbig Be stars. The shapes and positions of these lines are not consistent with those expected from a chromosphere and transition region (TR), which may be the origin of the other FUV emission lines in the spectra of these stars. The c…
High resolution UV stellar spectroscopy with the HST/GHRS, challenges and opportunities for atomic physics.
Leckrone, D. S.; Wahlgren, G. M.; Johansson, S. +1 more
The Goddard High Resolution Spectrograph (GHRS) on the Hubble Space Telescope (HST) is producing ultraviolet spectra of unprecedented resolution and photometric quality. The authors illustrate this with observations of the ultra-sharp-lined, chemically peculiar B-type star, χ Lupi. The photosphere of this star is rich in heavy elements, and its UV…
Discovery of an Optical Synchrotron Jet in 3C 264
Boksenberg, A.; Barbieri, C.; Weigelt, G. +17 more
Observations with the Faint Object Camera on board the Hubble Space Telescope have revealed a new optical jet in the core of the elliptical galaxy NGC 3862 (3C 264). Morphologically, this jet is similar to the synchrotron jets seen in other galaxies, as it shows knots and bifurcations. The optical spectral index [-d log I(v)/d log v = α = 1.4] is …
The Quasi-periodic Oscillations and Very Low Frequency Noise of Scorpius X-1 as Transient Chaos: A Dripping Handrail?
Scargle, Jeffrey D.; Steiman-Cameron, Thomas; Young, Karl +3 more
We present evidence that the quasi-periodic oscillations (QPO) and very low frequency noise (VLFN) characteristic of many accretion sources are different aspects of the same physical process. We analyzed a long, high time resolution EXOSAT observation of the low-mass X-ray binary (LMXB) Sco X-1. The X-ray luminosity varies stochastically on time s…
GINGA Observations of the Coma Cluster and Studies of the Spatial Distribution of Iron
Hughes, John P.; Tanaka, Yasuo; Butcher, Jackie A. +1 more
The large area counters on the Japanese satellite Ginga have been used to determine the X-ray spectrum from the central region of the Coma cluster of galaxies over the energy range from 1.5 to 20 keV. The spectrum is well represented by an isothermal model of temperature 8.21+/-0.16 keV and a heavy element (iron) abundance of 0.212+/-0.027 relativ…
Observations of the Gaseous Galactic Halo toward 3C 273 with the Goddard High Resolution Spectrograph
Savage, Blair D.; Morris, Simon L.; Gilliland, Ronald L. +2 more
We present an analysis of observations of 24 absorption lines produced zero redshift by Milky Way disk and halo gas along the sight line to 3C 273. The observations were obtained with the intermediate-resolution mode of the Goddard High Resolution Spectrograph (GHRS) using the large entrance aperture. The spectral spread function has FWHM ~20 km s…
The Narrow-Line Region of High-Luminosity Active Galactic Nuclei
Netzer, H.; Ferland, G. J.; Browne, I. W. A. +5 more
The HST's Faint Object Spectrograph and Kitt Peak ground instruments have been used to gather high S/N spectroscopic observations of seven radio-loud quasars; the resolutions obtained allow a separation of emission line broad and narrow components to be made. Attention is given to the relative weakness of the narrow UV lines, in contradiction to t…
Observations of the White Dwarf in the U Geminorum System with the Hopkins Ultraviolet Telescope
Blair, William P.; Sion, Edward M.; Kriss, Gerard A. +4 more
The Hopkins Ultraviolet Telescope was used to obtain an FUV spectrum of U Gem about 10 d after the end of an outburst. Most of the FUV emission from U Gem appears to rise from the white dwarf (WD) in the system. Various possibilities to explain the hot component in the present spectrum are explored. It is most likely due to radiation from the boun…
The Interstellar Abundances of Tin and Four Other Heavy Elements
York, D. G.; Welty, D. E.; Hobbs, L. M. +2 more
Spectra recorded at 1150-1600 A with an instrumental resolution near 16 km/s were obtained with the Goddard High-Resolution Spectrograph on board the HST. The gaseous interstellar abundances of five heavy elements along the light paths to 23 Ori, 15 Mon, 1 Sco, Pi Sco, and Pi Aqr were determined from the observations. The 1400.450 A line of Sn II …