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Electron densities for 10 planetary nebulae derived from the CIII 1907/1909 ratio. II.
Feibelman, W. A.; Hobbs, R. W.; Boggess, A. +1 more
Electron densities for IC 351, IC 2165, J900, IC 3568, NGC 6644, NGC 6891, IC 4997, NGC 7009, Hu 1-2, and IC 5217 are derived from high-dispersion semiforbidden C III spectrograms. For seven of these nebulae, the derived electron density is larger than the values derived from either surface brightness measurements or forbidden line ratios. Only on…
The 1979-1980 eclipse of ZET Aur. II. The emission spectrum.
Stencel, R. E.; Chapman, R. D.
UV observations using the IUE are employed to discuss the strength and changes of Zeta Aur between a second contact and mid-eclipse in 1979, the relative visibility of the supergiant's chromosphere as compared with the circumstellar (CS) nebular scattering of the B star photons, and the origin of the high speed CS components observed at all orbita…
Far-ultraviolet observations of the variable radio star LS I +61 303.
Maraschi, L.; Tanzi, E. G.; Treves, A.
One short wavelength spectrum, 1200-1950 A, and two long wavelength spectra, 1900-3200 A, have been obtained from IUE observations of the radio star LSI plus 61 deg 303 in September 1980. Assuming an E(BV) value of 0.9, as given by the rectification of the 2200 A absorption dip, the ultraviolet continuum is found to be fitted by a model atmosphere…
IUE monitoring of the spatial distribution of the H Ly-alpha emission from Jupiter
Feldman, P. D.; Moos, H. W.; Clarke, J. T.
North-south spatial maps of the Jovian H Lyman-alpha emission observed with the IUE satellite support the identification of a marked longitudinal asymmetry in the equatorial brightness, with the peak around lambda III(1965) = 50-100 deg longitude, and show a weaker planet-wide equatorial brightening above the level predicted by a plane-parallel la…
The ultraviolet spectrum of the high redshift QSO B2 1225+31.
Boksenberg, A.; Snijders, M. A. J.; Pettini, M.
We present low-resolution, near-ultraviolet observations of the bright (V=15.87), high redshift (Zem ≈ 2.2) QSO B2 1225+31, obtained with the IUE long wavelength camera. These spectra provide an important extension to the large body of optical and radio work carried out on this object. The QSO continuum in the ultraviolet agrees well wi…
Lanning 10 and 33 : the X-ray, uv, and optical fluxes.
Szkody, P.; Crosa, L.
UV spectra from IUE, optical spectroscopy, broad band photometry, and upper limits on the X-ray flux from Einstein are used to specify the characteristics of Lanning 10 and 33. Data on Lanning 33 are consistent with a 22,000 K Be star at a distance of 5 to 7 kpc, and Lanning 10 appears to include a F5-G0 star plus a hot component greater than 35,0…
IUE observations of four planetary nebulae.
Johnson, H. M.
Low dispersion spectra of NGC 6905 and NGC 5189 are reproduced. These are nebulae with 'O VI sequence' nuclei. Line features are identified and classified according to site in the nucleus or the nebula; their flux densities are measured above continuum and presented before and after correction for interstellar extinction. The behavior of the line …
Detection of Lyman continuum absorption in the BL Lacertae object PKS0735+178.
Huggins, P. J.; Bregman, J. N.; Glassgold, A. E.
The detection of the Lyman edge in the BL Lac object PKS 0735+178 at the absorption red shift determined by optical measurements leads to a lower limit for the column density of atomic hydrogen, N(H I) not less than 4(17)/sq cm. The Lyman-alpha absorption line appears to have been detected, but only an approximate upper limit can be obtained from …
The abundance of carbon in HU 2-1.
Lutz, J. H.
A logarithmic carbon abundance of 8.61 + or - 0.3 is derived for the planetary nebula Hu 2-1 using data taken with the International Ultraviolet Explorer satellite. This value is close to the logarithmic carbon abundance of 8.67 + or - 0.1, found for the sun by other investigators. The carbon abundance of Hu 2-1 is compared to those of other plane…
Line formation in the wind of alf Cyg.
Praderie, F.; Kunasz, P. B.
In the considered investigation, the method reported by Mihalas et al. (1976) is used to search for plausible atmospheric models for Alpha Cyg and to find limits on its mass-loss rate. Assumptions about the wind and underlying photosphere, and the free parameters of the model are described. The best-suited numerical method is discussed and possibl…