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Observations of the wind of the old nova V603 Aquilae with the HST-GHRS.
Selvelli, P.; Friedjung, M.; Cassatella, A.
High resolution spectra of the old nova V603 Aql (1918) were taken in the regions of the C IV, N V and Si IV resonance doublets, using the G160M grating of the GHRS on board the Hubble Space Telescope. No sign of sharp absorption components due to the envelope ejected in 1918 is present. If spherical symmetry is assumed, the estimated upper limits…
The early-type binary KX Velorum.
Drechsel, H.; Lorenz, R.; Mayer, P.
A spectroscopic study of the double-lined OB-type binary system KX Vel is presented. Radial velocities were measured on 20 new CCD spectra and 4 high dispersion IUE SWP images. From a combination with early photographic data, the orbital period was found to be 26.306d. The high precision radial velocity curve of the evolved primary component allow…
Optical and UV observations of the BL Lacertae object PKS 2155-304.
Wagner, S. J.; Heidt, J.; Wilhelm-Erkens, U.
The BL Lac object PKS 2155-304 has been monitored in two subsequent observing campaigns within three weeks in June 1990 and during another run in September 1994 at optical wavelengths. During the first part PKS 2155-304 showed night-to-night variations of a few percent, whereas in the second part no variability could be detected. During the third …
A spectral analysis of HDE 269445 from optical and infrared observations.
Schmutz, W.; Nota, A.; Origlia, L. +1 more
We present new, near-IR spectroscopic observations of HDE 269445, which we combine with published HST and IUE ultraviolet data and optical high resolution spectra. We discuss the spectral morphology of the star from UV to near-IR wavelengths, concentrating on profile variations in the UV and optical H and He lines. From a spectroscopic analysis wi…
Solar wind velocity jumps across tangential discontinuities: ULYSSES observations and kinetic interpretation
Tsurutani, B. T.; Roth, M.; de Keyser, J. +2 more
Some tangential discontinuities (TDs) observed by the Ulysses spacecraft interface solar wind regions that differ only in their bulk velocity and magnetic field orientation; composition, density, temperature and magnetic field intensity are essentially the same in both regions. The relation between the plasma velocity jump across the TD and the ma…
NGC 1427A - an LMC type galaxy in the Fornax cluster.
Infante, L.; Bomans, D. J.; Hilker, M. +1 more
We have discovered that the Fornax irregular galaxy NGC 1427A is in very many respects a twin of the Large Magellanic Cloud. Based on B, V, I, and Hα images, we find the following. The light of the galaxy is dominated by high surface brightness regions in the south-west that are superimposed by a half-ring of OB associations and Hii regions indica…
The EUV spectrum of κ Ceti: an active Sun.
Landini, M.; Del Zanna, G.; Landi, E.
The spectrum of κ Cet in the region 80-370Å observed by EUVE Spectrometers is analyzed to investigate the transition region and the corona of the star. The star appears to be in a rather quiet condition and no evidence exists of flare-like lines observed in many active stars. Several emission lines of moderately ionized iron (from Fe IX to Fe XVII…
Detection of young stellar objects with ISO.
Felli, M.; Gilmore, G.; Omont, A. +4 more
Preliminary 15µm results obtained with ISOCAM are compared with deep K-band and H_2_O maser observations of a 0.244deg^2^ field in the galactic plane at I=+45^o^. A new maser source is found to be associated with the infrared source with the largest colour index, (m_K_-m_15µm_)>=10, most probably a young star in its earliest evoluti…
Searching for chromospheric Lyman-α emission in A-F stars from IUE high resolution spectra.
Talavera, A.; Freire Ferrero, R.; Bruhweiler, F. +3 more
With the aim of locating the boundary for the onset of chromospheric emission in the H-R diagram we have undertaken a spectroscopic study of the hydrogen Ly-α, using the IUE short wavelength spectrograph in the high resolution mode. We report here on the analysis of IUE spectra of 11 A-F type stars. We have detected Ly-α emission in stars as early…
The close DAO+dM binary RE J0720-318: a stratified white dwarf with a thin H layer and a possible circumbinary disk.
Barstow, M. A.; Burleigh, M. R.; Dobbie, P. D.
We have analysed the EUVE spectrum of the DAO white dwarf RE J0720-318. In contrast to the optical spectrum, which can only be fitted with a homogeneously mixed H+He atmosphere, we find the EUVE spectrum can only be matched with a stratified structure. The H layer mass of 3x10^-14^M_[sun}_, is a factor of ~10 below upper limits from previous EUVE …