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Angular diameters, effective temperatures, radii and luminosities of 03, 04 and 05 stars.
Underhill, A. B.
UV and visible photometry is used to determine the effective temperatures, angular diameters, linear radii and luminosities of 24 O3, O4, and O5 stars. No correlation is found between effective temperatures, which ranged from 24,800 K to 63,000 K, and spectral type or luminosity class for the early O stars. Since conditions in the outer atmosphere…
The gaseous galactic halo as infrared from the line spectra of the galaxies Markarian 509 and Fairall 9.
York, D. G.; Cowie, L. L.; Blades, J. C. +3 more
Narrow interstellar absorption lines of S II 1259.52, Si II 1260.42, and Fe II 1608.46 due to gas in the disk and the halo of the Galaxy have been detected in the spectrum of the Seyfert galaxy Mrk 509 with the International Ultraviolet Explorer. This gas is also seen at higher resolution in the Ca II and Na I absorption lines in two components at…
The ultraviolet continuous and emission line spectra of the Herbig-Haro objects HH 2 and HH 1.
Nemec, J. M.; Boehm-Vitense, E.; Cardelli, J. A. +1 more
Recent studies of the continuous spectrum of Herbig-Haro (HH) objects at optical and near-infrared wavelengths and the observation of continuous radiation in the ultraviolet have shown an unexpectedly steep increase of the flux toward shorter wavelengths. The present investigation provides the results of ultraviolet observations of HH 2. The obtai…
The far-ultraviolet spectra and geometric albedos of Jupiter and Saturn
Feldman, P. D.; Moos, H. W.; Clarke, J. T.
Spectra and geometric albedoes in the range 1200 to 1940 A are compiled for Jupiter and Saturn on the basis of IUE observations. The spectra of both planets are dominated by H Lyman-alpha emission line at 1216 A, although absorption bands of C2H2 are apparent at longer wavelengths, particularly in the spectrum of Saturn, and the C I line at 1657 A…
Simultaneous observations of the BL Lacertae object I ZW 187.
Pollock, J. T.; Huggins, P. J.; Bregman, J. N. +15 more
Two sets of simultaneous spectra consisting of data obtained with radio, IR, optical, UV and X-ray telescopes were obtained 10 months apart for the X-ray bright BL Lac object IZw 187. In addition, nonsimultaneous observations were made in several of the aforementioned observing bands in order to detect flux variations and galactic light contaminat…
The ultraviolet spectrum of the center of M 31.
Welch, G. A.
A total of twelve long-exposure low-resolution IUE images have been used to study the spectrum and surface brightness distribution of the ultraviolet radiation within the central 50 pc of M31. The presence of weak absorption features near 1300 A demonstrates that the radiation of the well-known spectral upturn below 2000 A does not originate in yo…
Detection of auroral hydrogen Lyman-alpha emission from Uranus.
Clarke, J. T.
A series of observations of Uranus obtained with the short-wavelength spectrograph of the International Ultraviolet Explorer Observatory in 1982 April and June have revealed unexpectedly strong H Lyman-alpha emission which varied between 430 and 850 rayleighs in observed disk-averaged brightness over the course of these observations. The variabili…
The ultraviolet bands of the CO2/plus/ ion in comets
Feldman, P. D.; Weaver, H. A.; Festou, M. C.
Eight comets are studied with the International Ultraviolet Explorer spectrographs. The existence of the CO2(plus) ion in a comet is confirmed through the presence of the 2890 A doublet in at least three of these objects. Spatial and spectral resolution obtained in comets Bradfield (1979 X) and Seargent (1978 XV) permit a discussion of the product…
Evolution of chromospheres and coronae in solar mass stars : a far-ultraviolet and soft X-ray comparison of Arcturus (K2III) and alf CEN A (G2V).
Linsky, J. L.; Simon, T.; Ayres, T. R.
IUE far-UV and Einstein Observatory soft X-ray observations for the red giant Arcturus and the nearby yellow dwarf Alpha-Centauri A, which are archetypes of solar mass stars in different stages of evolution, are compared. Evidence is found for neither coronal soft X-ray emission from the red giant, at surface flux levels of only 0.0006 that detect…
The low state of AM HER : observations from 0.12 to 10 microns.
Raymond, J. C.; Szkody, P.; Capps, R. W.
Observations of AM Her during a low state over a wavelength range from 0.12 to 10 microns are reported. These include IUE ultraviolet spectra, light curves at U, B, V, R, J, H, K, and magnitudes at L, M, and N. The UV observations reveal a nearly Rayleigh-Jeans continuum spectral distribution and broad Lyman-alpha absorption from a hot (effective …