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X-Ray and Optical Observations of the X-Ray Source EX:0020528+1454.8
Richter, G. A.; Hudec, R.; Goetz, W. +7 more
We present preliminary results of the EXOSAT X-ray observations and quasisimultaneous and simultaneous optical photometry of the X-ray source EX0020528+1454.8=1E0205+149 found independently as an serendipitous source both with Einstein and EXOSAT satellites. The optical counterpart is a pair of dMe stars. Our results indicate that the object is va…
X-Ray and Ultraviolet Observations of Ag-Draconis during Quiescence and Outburst
Piro, L.; Córdova, F. A.; Friedjung, M. +3 more
We describe the first X-ray monitoring of a symbiotic star during phases of enhanced activity. AG Dra is a Pop II object with a composite spectrum, characterized by a cool K-type component, prominent high ionization emission lines and a strong UV continuum which is attributed to a hot dwarf companion. Periodic variability of the UV radiation durin…
EXOSAT Observations of X-Rays from Classical Novae during Outburst Stage
Beuermann, K.; Krautter, J.; Ögelman, H.
The initial discovery of soft X-rays from Nova Muscae 1983 was followed by eight additional observations of the three brightest novae whose outburst stage coincided with the lifetime ofEXOSAT satellite; namely three more observations of Nova Muscae 1983, three observations of Nova Vulpeculae 1984#1 (PW Vul), and two observations of Nova Vulpeculae…
EXOSAT and IUE Observations of the Symbiotic Binary R-Aquarii during Maximum and Minimum
Piro, L.; Friedjung, M.; Viotti, R. +1 more
Coordinated IUE and EXOSAT observations of the symbiotic Mira R Aqr, made in June and December 1985, at phases 0.0 and 0.5 of the Mira light curve, are discussed. A weak X-ray flux has been for the first time unambiquously detected without any significant change with the Mira light curve. Also the UV spectrum of the central object has not varied, …
Statistical Confirmation of the Ultraviolet Spectral Classification System Based on IUE Low-Dispersion Stellar Spectra
Heck, A.; Egret, D.; Nobelis, Ph. +1 more
In theIUE Low-Dispersion Spectra Reference Atlas (Hecket al., 1984a), a new spectral classification system specific to the UV had to be introduced because of the lack of one-to-one correspondence between the UV and visible ranges. It was elaborated from a classical morphological approach (Jaschek and Jaschek, 1984). This paper presents an independ…
Stellar chromospheres, coronae, and winds (invited review)
Simon, T.
Within the last few years there have been important advances in our understanding of the chromospheres, coronae, and winds of late-type stars. This progress has been the result of ultraviolet and X-ray observations obtained from space with theInternational Ultraviolet Explorer andEinstein satellites. In addition, ground-based astronomy has contrib…
The First Ultraviolet Studies of the Optical Candidate for the X-Ray Source 1118-61
Coe, M. J.; Payne, B. J.
The X-ray pulsator, 1118-61, discovered in 1975 by the Ariel-5 satellite, has been observed for the first time at UV wavelengths using IUE. Its UV spectrum clearly identifies the optical counterpart as a Be star similar to that seen in other X-ray pulsators. From the 2200 Å absorption feature a distance estimate of ∼ 4 kpc is obtained and the carb…
More on theλ2800 Å `interstellar extinction' feature
Nandy, K.; McLachlan, A.
We respond to comments made in a recent letter by Karimet al. (1984), and show that the examples of interstellar absorption atλ2800 Å that they have presented so far can all be attributed to overexposure of the IUE detectors.
Epsilon Aurigae
Chapman, R. D.
In April 1984, fourth contact ended the two year long eclipse of Epsilon Aurigae. An astrometric study of the study of the system was carried out by Van de Kamp (1978) leading to the conclusion that the orbit is seen very close to edge on. The eclipse was monitored by a number of groups from the ground and from spacecraft such as the IUE. Ultravio…
Variable, optically thick, hot plasma observed in interacting binaries
Kondo, Y.; McCluskey, G. E.; Parsons, S. B.
We report recent International Ultraviolet Explorer (IUE) observations of two interacting binaries, R Arae and HD 207739. The ultraviolet spectra indicate the presence of optically-thick, variable hot plasma in those binary systems. These two binaries may belong to a class of binaries that are currently undergoing a rarely observed and probably sh…