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Time-resolved ultraviolet and optical spectroscopy of the pulsating X-ray source H 2252-035.
Mason, K. O.; Cordova, F. A.; Fenimore, E. E. +1 more
Simultaneous ultraviolet and optical spectral measurements of the pulsating X-ray source H2252-035 have been made about its 3.6 hr binary orbital cycle with a time resolution of 30-70 minutes. A 2200 Å feature in the continous spectral distribution of the object suggests an amount of reddening corresponding to E(B-V) = 0.10 with 3 σ upper and lowe…
On the contributions of the Orion reflection nebulosity to the continuous UV spectrum of the Herbig-Haro objects HH1 and HH2 and of the C-Sstar.
Witt, A. N.; Mundt, R.
The possibility of contamination of the published UV continuum spectra of the Herbig-Haro objects HH 1 and HH 2 and the Cohen-Schwartz (C-S) star by the Orion reflection nebulosity (ORN) is pointed out. OAO 2 data suggest that the UV continuum observed in the environment of the C-S star may possibly be accounted for by the emission from the ORN. I…
Ultraviolet spectroscopy of V1341 Cygni (= Cygnus X-2).
Maraschi, L.; Tanzi, E. G.; Chiappetti, L. +1 more
Cyg X-2 is a low-mass X-ray binary of orbital period P = 9d.8. Several IUE spectra in the 1200-3000 Å range are examined. Variability up to a factor of 2 is apparent. A discussion of the emission-line spectrum yields estimates of the temperature (T ≈ 2×104K), density (n ≈ 2×1010 cm-3), and radius (r ≈ 5×…
Mass loss in HR 1040 (AO Ia) : analysis of MG IILambda 2802 and Hα.
Kunasz, P. B.; Morrison, N. D.; Spressart, B.
It is pointed out that International Ultraviolet Explorer (IUE) data for several early A type supergiants are now available to complement the ground-based spectroscopic data available for these bright stars. An examination of the resonance doublet of Mg II in the A type supergiants reveals that HR 1040 (HD 21389) is the only star in the observatio…
An attempt to determine stellar Lyman-Alpha emission-line fluxes for F stars with different metal abundances.
Bohm-Vitense, E.; Woods, J.
We have studied stellar Lyα fluxes for F stars of different metal abundances which are presumably older the more metal deficient they are. We describe the correction procedure for the geocoronal emission and our estimate of the correction for interstellar absorption. We find stronger than average Lyα emission for the Hyades stars and for the two c…
The evidence for shell formation in V1016 Cygni.
Nussbaumer, H.; Deuel, W.
V1016 Cyg is a candidate for being one of the youngest planetary nebulae ever observed. Its evolution is therefore followed with particular attention. The authors have investigated the claim of Feibelman that, early in 1982, a splitting developed in the C IV λ1551 line, indicating shell formation. Careful scrutiny of the spectra shows that claim t…
The galactic gamma-ray source population
Godfrey, C. P.
A procedure has been developed to estimate the contribution to the galactic gamma-ray emission by discrete sources under the assumption that the sources are distributed spatially like the total emission, but without regard to the nature of the individual sources. In particular, an analytical method is developed for calculating the fraction of the …
Erratum: "A multiwavelength comparison of Cassiopeia A and Tycho's supernova remnant" [Astrophys. J., Vol. 257, 145 - 150 (1982)].
Murray, S. S.; Dickel, J. R.; Morris, J. +1 more
The carbon abundance in the Magellanic Clouds from IUE observations.
Dufour, R. J.; Shields, G. A.; Talbot, R. J., Jr.
Results are given of observations of the UV spectra of several H II regions in the Magellanic Clouds, with emphasis on obtaining the carbon abundance from the UV lines of C II, C III, and C IV. The observations and results are described, and theoretical model calculations are presented of the H II regions and the relative abundances of H, He, C, N…
Outer atmospheres of cool stars. XII. A survey of IUE ultraviolet emission line spectra of cool dwarf stars.
Carpenter, K. G.; Linsky, J. L.; Worden, S. P. +4 more
Quantitative information is obtained on the chromospheres and transition regions of M dwarf stars, in order to determine how the outer atmospheres of dMe stars differ from dM stars and how they compare with the outer atmospheres of quiet and active G and K type dwarfs. IUE spectra of six dMe and four dM stars, together with ground-based photometry…