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NGC 40 : IUE observations of the nucleus.
Grewing, M.; Bianchi, L.
UV spectra of the nucleus of NGC 40 allow a derivation of an E(B-V) foreground reddening of 0.50 and a distance to the object of 980 pc; accordingly, T(eff) of 90,000 K, log L/L(solar) of 4.4, R of 0.66 R(solar), and M of 1.1 M(solar) are obtained. It is suggested that the discrepancy between the temperature determined from the UV emission of the …
Spectral Synthesis in the Ultraviolet. I. Far-Ultraviolet Stellar Library
O'Connell, Robert W.; Thuan, Trinh X.; Fanelli, Michael N.
A library of mean stellar energy distributions for use in population synthesis of the ultraviolet spectra of active star-forming galaxies is derived from the ultraviolet spectrophotometry in the IUE Spectral Atlas. The spectra extend from 1230 to 1930 A with a resolution of 6 A. The library contains eight main-sequence groups from O3 to A7 V, four…
The Composition and Dynamics of Cometary Ions in the Outer Coma of Comet p/ Halley
Schwenn, R.; Altwegg, K.; Balsiger, H. +15 more
During its flyby at comet Halley, the Giotto spacecraft encountered high densities of cometary ions inside approximately 200000 km from the nucleus. Their properties changed drastically as the comet was approached. We present here density profiles of solar wind alpha particles and of the major cometary ions as obtained by the IMS-HERS sensor betwe…
Ultraviolet Spectra of HH 1 and HH 2: Spatial Variations and the Continuum Problem
Raga, A. C.; Witt, A. N.; Brugel, E. W. +3 more
High-SNR 12-hr and 14-hr ultraviolet spectra of HH 1 and HH2 in the IUE short-wavelength range are reported. HH 1 data show a (spatial) half-width of the image size in the C IV 1548-A, 1551-A line which is smaller than the spatial half-width for the semiforbidden C II 1907-A, 1909-A line. A qualitatively similar situation is shown for HH 2, althou…
X-ray emission from the symbiotic system CH Cygni.
Leahy, D. A.; Taylor, A. R.
CH Cyg was observed with the EXOSAT LE1 telescope and CMA detector with 3 filters on 1985 May 24. The count rates indicate a soft X-ray spectrum with kT ≈ 0.1 keV and column density ≈4×1020 cm-2. The observed flux is ≈1.3×10-11erg cm-2s-1. An earlier upper limit obtained with the Einstein Imag…
Spectral evolution of SN 1987A in the far-ultraviolet.
Panagia, N.; Talavera, A.; Fransson, C. +4 more
Preliminary results are presented on the UV spectral evolution of SN 1987 A from IUE data obtained from February 25 to March 23, 1987. It is suggested that line blanketing, mainly from Fe II, Ni II and Ti II, variable with time, is probably responsible for the observed features. Black body fitting to the UV-optical-infrared energy distribution on …
First Unambiguous X-Ray Detection of R Aquarii
Piro, L.; Friedjung, M.; Viotti, R. +1 more
The authors report coordinated ultraviolet and X-ray observations of the symbiotic Mira R Aqr obtained with IUE and EXOSAT in 1985 June and December at phases 0.0 and 0.5 of the Mira light curve. They have detected with the Low-Energy EXOSAT detector a weak X-ray flux of 5.4 and 4.6×10-3 counts s-1 at the two epochs, respecti…
EXOSAT observations of the SNR PKS 1209-52.
Culhane, J. L.; Branduardi-Raymont, G.; Kellett, B. J. +3 more
Spatially resolved spectroscopy of the supernova remnant PKS 1209-52 and the point source within it is presented, based on observations made with the EXOSAT PSD detector. The authors find evidence that the shock front of the supernova remnant is interacting with an interstellar cloud. The data further indicate that the whole remnant is not in pres…
Ultraviolet Spectra and Chromospheres of Cool Carbon Stars
Johnson, Hollis R.; Luttermoser, Donald G.
The authors assemble and discuss all available low-resolution IUE spectra of N-type carbon stars - including TW Hor, BL Ori, UU Aur, NP Pup, U Hya, T Ind, and TX Psc. Identification of spectral features is aided by a composite spectrum. Shortward of 2850 A only emission lines of C II, Mg II, Al II, and Fe II are seen, while the spectrum longward o…
Interstellar lines in SN 1987A observed with the IUE.
Panagia, N.; de Boer, K. S.; Grewing, M. +3 more
The SN 1987A UV-interstellar spectrum shows nine resolvable components in ionization stages ranging from neutral gas (Mg I, Si II, Fe II, etc.) to highly ionized gas (Al III, Si IV, C IV). Three components are due to gas in the Milky Way disk and halo, four are most likely due to LMC gas, two components are at velocities intermediate to those of t…