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The 1982 eclipse of 31 Cygni.
Kondo, Y.; Stencel, R. E.; Chapman, R. D. +4 more
UBV photometry and optical-UV spectroscopy of the primary eclipse of the long period ζ Aurigae-like system 31 Cygni are reported. The precise timings made possible by the photometry imply that the spectral features could be due to an accretion shock associated with a hot star embedded in an extended chromosphere surrounding the red supergiant. The…
Rotational velocities of later B type and A type stars as determined from ultraviolet versus visual line profiles.
Sonneborn, G.; Carpenter, K. G.; Slettebak, A.
Theoretical line profiles of the Si III 1299 and Fe II 2756 lines are computed for rotating B5-A7 model stars, and compared with observed profiles from IUE spectra to derive rotational velocities. Real differences in widths for ultraviolet as compared with visual line profiles exist in the sample of B type stars (but not for the A type rapidly rot…
Similar photospheres, different mantles : a study of four O stars.
Underhill, A. B.
The present investigation is concerned with a comparison of the spectra of four O stars (10 Lac, S Mon, HD 46223, and Zeta Pup) which have similar effective temperatures, taking into account an attempt to find the reason for differences regarding the spectral type of the stars. The photospheres of the stars are examined, taking into account the ef…
The ultraviolet spectra of the O and B stars in the young galactic cluster NGC 6530.
Boehm-Vitense, E.; Hodge, P.; Boggs, D.
The UV spectra between 1200 and 3000 A of stars in the young galactic cluster NGC 6530 and the surrounding association are studied. From the UBV colors and empirical as well as theoretical calibrations, the T(eff) and L for those stars which follow a sequence in the H-R diagram corresponding to the main sequence are determined. From a comparison w…
The chromospheres of classical cepheids. III. A search for transition region emission lines.
Parsons, S. B.; Schmidt, E. G.
In previous studies of Cepheid chromospheres with the IUE, we found that the chromospheric emission is strongly dependent on the period of the star and varies substantially through the cycle. For the shortest period star in our sample, δ Cep, we were able to detect little significant chromospheric emission in the short wavelength region, and we we…
Ultraviolet high-resolution spectroscopy of the X-ray binary SK 160/SMC X-1.
Howarth, I. D.; Hammerschlag-Hensberge, G.; Kallman, T. R.
High-resolution IUE spectra of Sk 160, the optical counterpart of the X-ray source SMC X-1, show substantial variations with orbital phase of the resonance P Cygni profiles. These variations are ascribed to the changing ionization state in the stellar wind caused by the X-rays emitted by the companion, as suggested by Hatchett and McCray and first…
Ultraviolet and visible flare observations of EQ Pegasi B.
Raymond, J. C.; Baliunas, S. L.
EQ Peg AB (dM43+dM5.5e) was monitored in the visible at the Whipple Observatory and ultraviolet with IUE on September 2, 1981. In the visible spectrophotometry of EQ Peg B the H-beta emission strengthened by a factor of 2 relative to the nearby stellar continuum within a few minutes and decayed over an hour. This flare in EQ Peg B was coincident w…
Ultraviolet interstellar absorption toward stars in the Small Magellanic cloud. II. SK 159.
Fitzpatrick, E. L.
On the basis of a study of high-dispersion spectra of stars in the Large and Small Magellanic Clouds (LMC and SMC) obtained with the International Ultraviolet Explorer (IUE) satellite, Savage and de Boer (1979, 1981) have detected the Milky Way halo gas. The existence of gaseous coronae around both the LMC and SMC was also suggested. The evidence …
The far-ultraviolet energy distribution of Sirius B from Voyager 2.
Wesemael, F.; Holberg, J. B.; Hubeny, I.
Observations of Sirius obtained with the Voyager 2 ultraviolet spectrometer clearly reveal the presence of flux from the white dwarf Sirius B at wavelengths between 950 and 1100 A. These observations are in good agreement with all previous ultraviolet observations of Sirius B, and in particular with the IUE observations of Boehm-Vitense, Dettmann,…
The ultraviolet spectrum of a strongly reddened, high-excitation Herbig-Haro object.
Bohm-Vitense, E.; Bohm, K. H.
Short- and long-wavelength IUE spectra of the rather strongly reddened, high radial velocity Herbig-Haro object HH 32A have been obtained. The object is well known for its large positive radial velocity and for its unusually large velocity dispersion. In consequence of the large ultraviolet extinction, the spectra are faint. The semiforbidden C II…