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The optical and ultraviolet spectrum of the planetary nebula NGC 2440.
Czyzak, S. J.; Shields, G. A.; Keyes, C. D. +1 more
New measurements of the optical and ultraviolet emission-line intensities of the high-excitation planetary nebula NGC 2440 in the wavelength range 1240-8578 A are analyzed with the aid of photoionization models. The observed O III and N II forbidden-line temperatures (13,800 K and 10,000 K, respectively) differ by more than the models predict. Inc…
A model of V1016 CYG based on the ultraviolet spectrum.
Nussbaumer, H.; Schild, H.
The ultraviolet spectrum of the suspected symbiotic star V 1016 Cygni is interpreted in terms of a single star model. Spectra were obtained at low and high resolutions in the range 1100 to 3200 A by the IUE. From analyses of spectral features including the forbidden Ne V lines, He II UV recombination lines and the continuum flux, an interstellar r…
Physical conditions in the nucleus of M 81.
Torres-Peimbert, S.; Peimbert, M.
IUE and visual observations of the emission lines in the nucleus of M8 1 are presented. The permitted lines show broad and narrow features qualitatively similar to those in Seyfert galaxies. The observed luminosity for the broad component is L(Hβ) = 7.4 × 1037 ergs s-1, which is about two orders of magnitude smaller than in t…
Ultraviolet observations of hot stars with circumstellar dust shells.
Savage, B. D.; Sitko, M. L.; Meade, M. R.
Absolute fluxes over the wavelength range 1200-3200 A are presented for 13 normal early-type stars and 12 early-type stars known to have large IR excess; the data were obtained to study the UV spectral modifications produced by absorbing circumstellar dust particles. It is found that all the Be/shell stars whose spectral types are later than B6 ex…
Nova Cygni 1978 - I. The nebular phase.
Snijders, M. A. J.; Seaton, M. J.; Stickland, D. J. +2 more
UV observations of Nova Cygni 1978 have been obtained using IUE on 17 dates between 1978 September 12 and 1979 July 8 inclusive. The discussion includes the interpretation, during the nebular stage, of the UV observations together with optical and IR data from other observers. Analysis of the available data indicates that Nova Cygni 1978 was produ…
Detailed observations of NGC 4151 with the IUE. I. Low dispersion data up to 1979 january.
Tanzi, E. G.; Tarenghi, M.; Perola, G. C. +12 more
Low resolution ultraviolet spectroscopic monitoring of NGC 4151, the brightest Type 1 Seyfert galaxy, with the IUE from February, 1978 to January, 1979, is presented. Data acquisition and reduction are described. Observations were made at seven different epochs. Optimum exposure times, when the object is bright, were found to be 25-30 min and 50-6…
Ultraviolet spectra of planetary nebulae. III. Mass loss from the central star of NGC 6543.
Lutz, J. H.; Seaton, M. J.; Castor, J. I.
An ultraviolet spectrum of the central star of NGC 6543 has been obtained at low dispersion with the short wave camera of the IUE satellite, and the terminal velocity of the stellar wind has been estimated at 2150 km/s. By assuming the effective temperature to be the Zanstra temperature of 43,000 K and the luminosity to be that derived from the ev…
The nearby interstellar medium
Frisch, P. C.
The high dispersion spectrometer on board the International Ultraviolet Explorer (IUE) satellite was used to observe interstellar absorption lines in Rasalhague (α Oph). This star is located 18 pc from the Sun in the direction of the North Polar Spur, a prominent radio continuum feature in the Ophiuchus region of the sky. The satellite results, co…
Coordinated X-ray, ultraviolet and optical, observations of AM Her, UGem and SS Cyg.
Branduardi-Raymont, G.; Fabbiano, G.; Raymond, J. +3 more
Simultaneous and quasi-simultaneous optical, UV and X-ray observations of the accreting degenerate dwarf stars AM Herculis, U Geminorum and SS Cygni are reported. The observations were obtained in March 1979, by instruments on board the Einstein Observatory and the IUE satellite, and optical properties were monitored on the ground. AM Her was foun…
IUE spectroscopy of cataclysmic variables.
Vogt, N.; Wolf, B.; Krautter, J. +4 more
The continuum flux distribution and line spectra of six cataclysmic variables detected by the IUE are studied. The spectrophotometry with intermediate spectral resolution around seven A allows derivation of extinction values, temperatures, and the sizes of the radiating areas. V603 Aql, RRpic, HRDel, and TT Ari, which have similar absolute dimensi…