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Far-ultraviolet observations of MV Lyr.
Maraschi, L.; Tanzi, E. G.; Chiappetti, L. +1 more
Ultraviolet observation of MV Lyrae in the low state obtained with the IUE are presented, and their implications in establishing the nature of the system are examined. The line spectrum from 1200 to 3100 A exhibits weak absorption and emission features and is consistent with the estimated distance of 320 pc. The shape of the continuum is close to,…
Interpretation of line profiles of the symbiotic star V1016 Cyg.
Nussbaumer, H.; Kindl, C.; Marxer, N.
Profiles of the strongest UV emission lines of the symbiotic star V 1016 Cyg have been extracted. These profiles are compatible with the assumption that V 1016 Cyg is very young planetary nebula. The line profiles show two components. The narrow main component originates in the nebular shell. It is concluded that the wide feet are due to emission …
The detection of interstellar C I in the immediate vicinity of the sun
Kondo, Y.; Bruhweiler, F. C.
Multiple stacked IUE spectra reveal the presence of interstellar C I 1657 in the trough of a corresponding photospheric feature in the nearby star, Alpha PsA (d = 7 pc). This represents the first detection of this neutral atom in the interstellar medium within the immediate vicinity of the sun. It is suggested that C I may be a much better diagnos…
Molecules in celestial objects - III. Study of CO in interstellar diffuse clouds.
Krishna Swamy, K. S.; Tarafdar, S. P.
The absorption lines corresponding to the A-X transition of CO have been looked for in the IUE spectra of 14 stars with varying values of the colour excess, E(B-V) and found to be present in the spectra of nine stars with E(B-V) at least 0.28. The column density of CO has been determined towards these nine stars and its upper limit towards the res…
New evidence of strong UV radiation in TT Ari.
Vogt, N.; Drechsel, H.; Rahe, J. +1 more
Three SWP spectra and one LWR spectrum of the cataclysmic variable TT Ari were obtained with the IUE satellite during three different brightness phases, including the brightness minimum of November 1980. The absolute continuum intensity distribution in the UV and optical regions is examined in relation to several steady-state optically thick accre…
On the spin down episodes of Vel X-1.
Molteni, D.; Robba, N. R.; Rapisarda, M. +1 more
The ESA COS-B satellite observed the X-ray source Vela X-1 in July/August 1976 and in October/November 1979 in the energy range 2-12 keV. Different pulse periods, 282.819 and 282.782 s, were determined for the two observations respectively. These values confirm the presence of spin up and spin down processes in this source.
Mira B.
Stickland, D. J.; Cassatella, A.; Ponz, D.
A high resolution IUE spectrum of Mira taken at the time of the 1980 maximum shows sharp emission features from the M star and broad ones attributable to a large volume of gas around the hot companion. Some information on the emission from the vicinity of Mira B is available from line widths and ratios.
C IV and Lyman-alpha emission lines in Seyfert 1 galaxies
Stoner, R.; Ptak, R.; Gregory, S.
Good resolution spectra of C IV and Lyman-alpha emission in four Seyfert 1 galaxies (NGC 5548, NGC 4151, NGC 3738, and Fairall 9) are examined, reporting the line profiles and intensity information for this emission. The observations are made with the short wavelength prime camera on the IUE satellite, with a spectral coverage from 1150 A to 2000 …
Abandances in the planetary nebula NGC 6853.
Pottasch, S. R.; Wesselius, P. R.; Gilra, D. P.
IUE ultraviolet spectra have been analysed of several portions of planetary nebula NGC 6853. Combining these measurements with those made from the ground, we are able to determine the relative abundances of C, N, O, and Ne, without making any important assumption concerning the ionization of any of these elements. C, O, and Ne have solar abundance…
The X-ray flux variations of CYG X-2.
van der Klis, M.; Bonnet-Bidaud, J. M.
Results of a 47 d observation of Cygnus X-2 by the COS-B X-ray experiment are presented. The observed variability of the X-ray intensity is investigated for the presence of modulation at either the 9.843 d optical period or the 11.23 d X-ray period claimed for this source. Upper limits are given to pulse amplitudes for periods between 1 d and 200 …