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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…
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…
The C IV 1550 profile in type 1 Seyfert galaxies.
Gull, T. R.; Boggess, A.; Wu, C. -C.
The paper presents C IV 1550 A line profiles for the type 1 Seyfert galaxies NGC 5548, Mrk 509, NGC 7469, and MCG-2-58-22. Several line broadening mechanisms and theoretical line profiles are considered, and random motion of discrete clouds is ruled out. A spherical ensemble of discrete clouds with steady outflow or inflow produces a logarithmic p…
IUE ultraviolet spectra of the interacting binary U Cep.
Kondo, Y.; McCluskey, G. E., Jr.; Harvel, C. A.
Twenty-one mid-ultraviolet and three far-ultraviolet spectra of the close interacting binary U Cephei have been obtained with the International Ultraviolet Explorer. The results show that the gas stream leaves the G star, circuits around the B companion some 270 deg and leaves the binary system, confirming the preliminary results. Additional sourc…
Ultraviolet slit spectroscopy in the core of 30 Doradus with the International Ultraviolet Explorer
Koornneef, J.; Mathis, J. S.
Low resolution (about 7 A) IUE observations of the core of the 30 Doradus Nebula in the Large Magellanic Cloud are presented. Data were obtained through the large entrance aperture at 11 different positions in both the long wavelength (1900-3200 A) and short wavelength (1150-2000 A) cameras. The aperture was stepped in 10-arcsec intervals, in the …
A compressed cloud in the VELA supernova remnant
Jenkins, E. B.; Wallerstein, G.; Silk, J. +1 more
Strong interstellar absorption lines of C I, arising from the two excited fine-structure levels, are found in IUE observations of HD 72350 (type B4 III). An analysis of the excited-level populations of C I gives local temperature and pressure limits, and auxiliary data on the limit of column density for excited O I and the carbon ionization help t…
On the nebulosities associated with the extreme of star HD 148937.
Gull, T. R.; Bruhweiler, F. C.; Henize, K. G. +1 more
In order to understand the origin of the extreme Of star HD 148937, a study was undertaken of the interrelations between (1) its associated nebulae, including NGC 6164-5, (2) a 2 deg diameter H II region, (3) an outer dust shell, and (4) a newly identified interstellar bubble. A self-consistent model describing the interaction of HD 148937 with th…
Observations of strong ultraviolet absorptions in the spectrum of theDC white dwarf G 218-8.
Wegner, G.
The spectrum of the 14th magnitude DC white dwarf G218-8 (EG 245) is described. In the visible spectral region the star has been observed with the IIDS scanner attached to the Kitt Peak National Observatory 2.1 m telescope, where it shows a featureless spectrum. However, the ultraviolet observations using the IUE satellite show that strong absorpt…