1,720,972 research outputs found
Objective Prism Study of the 1977 Spectrum of HDE 245770=A0535+26
No full textObjective prism plates of the optical"
"counter.part of the transient X-ray source A0535+"
"26 obtained during 1977 show strong H""' in emis sion and marked Balmer excess. Many other emis sion lines are probably present in the red-infra red.No large spectral time variation was foun
A Spectrophotometric Study of Ultraviolet and X-ray Sources with Objective Prism Plates
No full textSeveral objective prism spectra of objects known to have large ultraviolet or X-ray fluxes are discussed. A marked Balmer excess and H alpha emission are found in X Per(= 3U 0352 + 30) and in the similar Be star HD 200775. No Balmer discontinuity is detectable in HD 226868 (Cyg X-1) during the low X-ray states, in HZ 43 (MX 1313 + 29), and in the hot subluminous star BD + 37 deg 1977. Comparison with the far ultraviolet spectrum of this star (Carnochan et al., 1975) leads to the conclusion that the star is slightly reddened (EB-V = 0.15 plus or minus 0.05) with an optical-ultraviolet energy distribution close to a 100,000 K black-body
Nova Cygni 1978
No full textA. Altamore, Istituto Osservatorio Astronomico Universita' di
Roma; R. Viotti, Laboratorio di Astrofisica Spaziale, Frascati; and
G. B. Baratta, Osservatorio Astronomico di Roma, telex: "Nova Cyg
1978 was observed on Sept. 12.0 and 14.0 UT with the Schmidt telescope
of the Rome Astronomical Observatory at Campo Imperatore.
Several objective-prism spectrograms were obtained on IIa-O and I-N
emulsions. The Sept. 12 spectrograms are overexposed, and only a
few features are detectable: Balmer H10 and H11 in emission, Ca II
3933 A, 3968 A and a strong structure at 3920 A (probably Mg I 3838 A)
in absorption. The Sept. 14 spectrum shows broad Balmer emission
lines from H-alpha to H11. Fe II blends (4450-4620, 4210-4310,
4140-4190 A) are strong in emission. In absorption there are present:
Ca II 3933 A, 3968 A with a violet shift of about 15 A; Ca I 4227 A
and the probable Mg I 3838 A. The ultraviolet continuum is strong.
Atmospheric phenomena in ETA carinae and the Hubble-Sandage variables
No full textFrom the analysis of the galactic counterparts of the HS variables, η Car, AG Car and P Cyg we conclude that their atmospheres are near critical
physical conditions so that small changes of the mass outflow could produce a large variation of the atmospheric structure and nova-like explosions at
nearly constant Mbo1
The X-ray spectrum of emission line stars (superluminous and symbiotic)
No full textThe observation of the X-ray spectrum of peculiar emission line stars, whose atmospheric envelopes are characterized by extreme physical conditions, represents an important tool to investigate the processes of formation of high temperature plasmas. The authors discuss the case of the superluminous object η Car showing both high and low temperature regions and an asymmetric wind. They present new EXOSAT observations of symbiotic stars. AG Draconis observed at a minimum phase shows a low temperature X-ray spectrum. A weak flux from the Mira variable R Aqr observed near maximum has been also detected
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