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Long- and short-term variability of the T Tauri star RY Lupi.
Liseau, R.; Gahm, G. F.; Fischerstrom, C. +1 more
Data are presented on spectroscopic and photometric observations of the T Tauri star RY Lupi carried out since 1981 from the FUV to the IR spectral region. These data show a remarkable kind of variability of the RY Lupi. Namely, the FUV and the IR fluxes, as well as the fluxes in H-alpha and H-beta are relatively constant, while the range in V mag…
The colour of Comet P/Halley's nucleus and dust
Keller, H. U.; Thomas, N.
Results are presented on the absolute calibration of the Halley Multicolor Camera (HMC), showing that HMC is 24 less sensitive than previously thought. The results are used to determine the reflectivity of the nuclear surface of the P/Halley comet, its color, and the color of the dust within 300 km of the nucleus. Results showed that the nucleus o…
Ultraviolet Spectrophotometry and Optical and Infrared Photometry of the Old Nova GK Persei
Raymond, John C.; Wu, Chi-Chao; Swank, Jean H. +3 more
IUE observations in the 1150-3250-A region were obtained of GK Per during the rise, at the maximum, and during the decline of the 2.5-mag optical outburst in 1981. The results support previous predictions for the interaction of an accretion disk with the magnetic field of an accretion star. The luminosity at minimum is found to be 2.3 solar lumino…
Active phenomena in the pre-main sequence Herbig AE star HD 163296.
Talavera, A.; Catala, C.; Simon, T. +3 more
Observations by IUE of the short-term variability of the Mg II and Ca II resonance lines in the Herbig Ae star HD 163296 are presented. Evidence that these lines show a phenomenon of rotational modulation, similar to the one observed in AB Aur, another Herbig Ae star is found. The variations in the spectrum of HD 163296 are even more conspicuous t…
Fast Winds in Central Stars of Some Planetary Nebulae
Perinotto, M.; Cerruti-Sola, M.
Winds from the central stars of the planetary nebulae NGC 1535, NGC 6210, NGC 7009, IC 418, and IC 4593 have been investigated with high-resolution IUE spectra. All these stars present P Cygni profiles in some of the following lines: N V 1240, O IV 1342, O V 1371, Si IV 1397, C IV 1549, and N IV 1719 A. These profiles have been analyzed with the S…
Effective temperatures of AP stars.
Stepien, K.; Dominiczak, R.
A new method of determination of the effective temperatures of Ap stars is suggested in which at first the temperature of a model best reproducing the observed visual energy distribution is determined and then a correction to this temperature resulting from the UV flux deficit is added. The method is calibrated on a sample of stars with energy dis…
Ultraviolet Observations of Interstellar Absorption Lines toward SN 1987A
Jenkins, Edward B.; Savage, Blair D.; Joseph, Charles L. +1 more
An average of all high-resolution UV spectra of SN 1987A recorded by IUE a few days after the explosion reveals numerous interstellar absorption lines between 1200 and 3100 A. Features produced in the neutral medium of our Galaxy and the LMC (e.g., those arising from O I, C I, C II, Mg I, Mg II, Fe II, Mn II, Si II, Ni II, etc.), together with lin…
He 2-104: A Link Between Symbiotic Stars and Planetary Nebulae
Shaw, Richard A.; Lutz, Julie H.; Kaler, James B. +2 more
Ultraviolet, optical and infrared observations of He 2-104 are presented, and estimates for some of the physical properties of the nebular shell are made. It is argued that He 2-104 is in transition between the D-type symbiotic star and bipolar planetary nebula phases and, as such, represents a link between subclasses of these two types of objects…
The Discovery of 2.93 Hour Periodic Intensity Dips from X1323-619
Parmar, A. N.; van Paradijs, J.; van der Klis, M. +1 more
A 30 hr duration Exosat observation of the low-mass X-ray binary X1323-619 is reported. The 1-8 keV light curve obtained with the medium-energy (ME) instrument shows irregular intensity dips that recur every 2.93 hr as well as type 1 X-ray bursts. The intensity declines to about 50 percent of its unaffected value during the 50-minute duration dips…
Absorption dips and the properties of the accretion stream in polars.
Motch, C.; King, A. R.; Watson, M. G. +1 more
Simultaneous X-ray, optical and infrared observations of the absorption dips in the polar system EF Eri are presented. These observations are used to determine the properties of the dips and develop a simple model for the dips in which they are caused by absorption in the accretion stream as it crosses the line-of-sight to the X-ray/optical emissi…