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The optical and ultraviolet spectra of the high excitation planetary nebula, CD -23 12238 = ME 2-1.
Czyzak, S. J.; Keyes, C. D.; Aller, L. H.
Planetary nebula are now recognized as a penultimate stage in the evolution of many stars. Me 2-1 offers advantages meriting a detailed analysis. A description is presented of measurements regarding this object which have been conducted with a photoelectric scanner and a 3 m telescope Cassegrain image tube scanner. The chemical composition of Me 2…
Ultraviolet spectra of planetary nebulae. IV. The CIII 2297 dielectronic recombination line and dust absorption in the CIV 1549 resonance doublet.
Harrington, J. P.; Lutz, J. H.; Seaton, M. J.
Calculations by Storey confirm, as suggested in Paper I of the present series, that dielectronic recombination via low-lying auto-ionizing states is important for the calculation of the ionization equilibria of carbon ions. These processes also produce various spectrum lines, of which one is C III 2p2 1D → 2s 2p 1P…
The ultraviolet spectrum of the active elliptical galaxy NGC 1052.
Boksenberg, A.; Penston, M. V.; Snijders, M. A. J. +1 more
Low resolution IUE observations of NGC 1052 in both the long and the short wavelength regions are reported along with optical multi-aperture photometry. It is found that the ultraviolet energy distribution of NGC 1052 is similar to that of other normal galaxies observed with IUE, having a large excess at short wavelengths above the extrapolation o…
Rotation of dwarf star chromospheres in the ultraviolet.
Hallam, K. L.; Wolff, C. L.
Periodic variations in the ultraviolet fluxes of chromospheric emission line multiplets are investigated for F, G and K stars as evidence of rotational modulation. Vacuum ultraviolet spectra were obtained with the IUE spacecraft for six stars as many as 11 times over the period April 23 to December 3, 1980. Variations in the emission fluxes of the…
The resonnance line of B II in IUE spectra of chemically peculiar stars.
Leckrone, D. S.
A description is presented of high-dispersion spectroscopic observations of eight chemically peculiar stars including Kappa Cnc and Mu Lep, and of one normal comparison star, Nu Cap, in the vicinity of 1362 A. The reported data were obtained with the International Ultraviolet Explorer during the first 15 months of its operation. The initial reduct…
Variability of the continuum and the emission lines in the Seyfert 1 galaxy Akn 120.
Kollatschny, W.; Yorke, H. W.; Fricke, K. J. +1 more
IUE and visual spectrophotometry of Markarian 9, Markarian 10, and 3C 390.3.
Oke, J. B.; Goodrich, R. W.
Ultraviolet spectra from IUE are combined with visual spectra for the three type I Seyfert galaxies Mrk 9, Mrk 10, and 3C 390.3. The 2175 A interstellar feature is measured well enough in Mrk 9 to indicate that the extinction corresponding to E(B-V) = 0.14 + or - 0.04 is in the galaxy. Mrk 10 displays evidence for 2175 A absorption and also yields…
The ultraviolet properties of dust in the Orion Nebula.
Patriarchi, P.; Perinotto, M.; Mathis, J. S. +1 more
The continuum in the Orion Nebula was observed with the IUE at 16 positions varying from 30 arcsec to 5 arcmin in angular separation from the central star Theta(1) Orionis C. The atomic continuum was estimated from the H-beta brightnesses. The remaining scattered starlight was analyzed by multiple-scattering models in which the main parameters are…
Observations of Uranus, Neptune, and Titan by the International Ultraviolet Explorer
Owen, T.; Caldwell, J.; Butterworth, P. S. +3 more
The ultraviolet spectra of Uranus, Neptune, and Titan do not reveal absorption features at 7-A resolution from 2100 to 3200 A. Upper limits of from 1 to 3 A are set for the equivalent widths of narrow absorptions, which corresponds to a CO/H2 mixing ratio less than 2 x 10 to the -4th in the case of Uranus. The slopes of the continuum reflectivitie…
Far UV study on the non-thermal activity in the narrow line galaxies NGC 4507 and NGC 5506.
Maccacaro, T.; Bergeron, J.; Perola, C.
The narrow line high excitation galaxies NGC 4507 and NGC 5506 were observed with IUE satellite in the low resolution mode. The continua of both galaxies, when combined with optical observations, show a flattening at log nu greater than 14.9. The reddening correction cannot be estimated with accuracy. The energy content in the Lyman continuum is l…