Search Publications
34.1 day periodicity in CYG X-3
Molteni, D.; Robba, N. R.; Scarsi, L. +1 more
COS-B observations of a 34.1-day periodicity in the X-ray intensity of the X-ray source Cyg X-3 are discussed. Collimated proportional counter observations of the source were made in the 2-12 keV energy range for a total of approximately 100 days in three intervals of approximately one month each; data from two of these intervals allow the monitor…
IUE observation of strong UV absorption in the spectrum of the C2 white dwarf ion of LP 145-141.
Koester, D.; Weidemann, V.; Vauclair, G.
An absorption feature of exceptional strength has been observed by IUE around 1900 Å in the spectrum of the cool (7500 K) degenerate "λ467O" or "C2" star LP 145-141. Molecule formation is shown to be favoured in helium-rich, high pressure white dwarf atmospheres, with CO, C2 or O2 dominant, depending on the He/C an…
UV spectrograms of T Tau stars.
Wolf, B.; Mundt, R.; Appenzeller, I. +2 more
The IUE satellite has been used to observe the ultraviolet spectra (1200-3200 A, 6A resolution) of the T Tauri stars DR Tauri, CoD-35 deg 10525, and AS205. In addition, earlier IUE spectrograms of the T Tauri star S CrA were rereduced using a more effective procedure. The new IUE observations were supplemented by simultaneous (or nearly simultaneo…
Infrared photometry of HDE 226868 (Cyg X-1) from 2.3 to 10 MU : mass loss rate.
Persi, P.; Ferrari-Toniolo, M.; Grasdalen, G. L. +1 more
Infrared photometry between 2.3 and 10 microns, shows an ionized gaseous envelope surrounding the supergiant OB star HDE 226868, the optical counterpart of the X-ray binary system Cyg X-1. The mean extent of the envelope at 10 microns is approximately 1.3 R (asterisk). The mass loss rate of HDE 226868 derived from 10 microns ff + bf emission flux,…
Characteristics of the Cen X-3 neutron star from correlated spin-up and X-ray tics luminosity measurements .
van der Klis, M.; Robba, N. R.; Bonnet-Bidaud, J. M.
Results are presented of one month of observations with the ESA COS-B satellite of the X-ray pulsation period of Cen X-3, together with X-ray luminosity measurements during this same time.
The data are shown to be compatible with an unbraked spin-up by accretion from a Keplerian disk onto a neutron star with f = 4µ2/730<…Copernicus observations of neutral helium lines in early-type stars.
Dufton, P. L.; McKeith, C. D.
Observations of stellar ultraviolet He I lines at 2829, 2945, and 3187 A obtained with the Copernicus Satellite, are compared with LTE and non-LTE calculations. The stars observed cover the range of spectral types O8-B7 and luminosity Classes I-V and were chosen to have relatively low projected rotational velocities. The equivalent widths measured…
The recent outburst of the dwarf nova WZ Sge.
Rafanelli, P.; Ortolani, S.; Vittone, A. +1 more
Spectroscopic observations of the 1978 outburst of the singular cataclysmic variable WZ Sagittae are reported. Spectra taken near maximum and during the decline reveal weak emission lines of H alpha, H beta, He II 4686, and N II 4640 and absorption lines of hydrogen, He I and possible N II over a strong continuum well extended in the violet. UV sp…
Highly ionized species in the spectra of Small Magellanic Cloud stars
Ferlet, R.; Vidal-Madjar, A.; Lequeux, J. +7 more
Preliminary results of high-resolution IUE observations of the star Sk 159 in the Small Magellanic Cloud (SMC), and of low-resolution observations of this star and of six other SMC stars are presented. A study of C IV and Si IV circumstellar absorption suggests a stellar mass loss rate smaller than in the Galaxy and the large Magellanic Cloud. Int…
Astrophysical interpretation of the lam lam 1200-7300 angstrom emission line spectrum of a filament in the CYG Loop Supernova remnant.
Dennefeld, M.; Benvenuti, P.; Dopita, M. A. +2 more
An IUE spectrum of a filament in the Cygnus Loop supernova remnant obtained with the low resolution, long wavelength camera, has been combined with earlier far UV and optical data to obtain a complete spectral coverage between 1200 and 7350 Å. The observed continuum is fully understood as a combination of free-free emission, recombination and hydr…
Ultraviolet, optical, and infrared observations of the Herbig Be star HD 200775.
Altamore, A.; Baratta, G. B.; Viotti, R. +3 more
The Herbig Be star HD 200775, associated with the extended reflection nebulae NGC 7023, has been observed in the ultraviolet with the IUE satellite, in the optical with the 90-cm Schmidt telescope of Campo Imperatore Observatory, and in the infrared with the 2.3 m telescope of Wyoming University in a coordinated campaign made during August 1978. T…