Search Publications
International ultraviolet explorer spectroscopy of hot stars in the LMC and SMC : the SMC extinction law, stellar flux distributions, and details of the stellar winds.
Hutchings, J. B.
IUE high- and low-dispersion spectral observations of hot stars in the Small Magellanic Cloud and Large Magellanic Cloud are presented. The extinction curve for the SMC derived from the data is much steeper in the UV than those of the LMC or the Galaxy. Based on stellar continuum data, stellar temperatures in the Magellanic Clouds are found to be …
The UV spectra of nearby white dwarfs and the nature of the local interstellar medium.
Kondo, Y.; Bruhweiler, F. C.
Detailed results from analysis of the IUE ultraviolet data obtained in the directions of the white dwarfs G191-B2B, W1346, HD 149499B, and Sirius B are presented. It is found that the sun is embedded in a low-density cloud extending to about 2-3 pc in most directions, with some evidence suggesting that the sun may be near the edge of the cloud. Th…
Detailed observations of NGC 4151 with the IUE -II. Variability of the continuum from 1978 february to 1980 may, including X-ray and optical observations.
Tanzi, E. G.; Tarenghi, M.; Perola, G. C. +13 more
NGC 4151 has been extensively monitored with IUE from 1978 February to 1980 May. The rather erratic behaviour of the ultraviolet light curve seems to be mainly due to variations which occur at rates which, if extrapolated, would produce factor two changes in time-scales between five and 30 days, implying a radius of the order of 0.01 pc for the so…
On the reality of a boundary in the H-R diagram between late-type stars with and without high temperature outer atmospheres.
Stencel, R. E.; Linsky, J. L.; Simon, T.
The Linsky-Haisch hypothesis (1979) that a boundary exists in the H-R diagram separating yellow giants from red giants and supergiants is tested. IUE 1150-2000 A low-resolution spectra of 10 stars chosen to constitute a reverse bias sample are presented and discussed. Despite the bias, weak C IV emission indicative of high-temperature plasma was o…
IUE observations of NGC 4649, an elliptical galaxy with a strong ultraviolet flux.
Capaccioli, M.; Oke, J. B.; Bertola, F.
As in the previously studied elliptical galaxies, the flux f(lambda) in NGC 4649 has a minimum at 2500 A followed by a rapid increase towards shorter wavelengths. In NGC 4649, the flux level of this rising branch is the highest so far observed and seems not to be correlated with the luminosity or activity in the galaxy. The excess shortward of 400…
On the linearity of the SWP camera of the IUE : a correction algorithm.
Bohlin, R. C.; Cassatella, A.; Schiffer, F. H. +2 more
An algorithm is presented for correcting IUE low resolution spectral images obtained with the SWP camera for some of the non-linearity effects reported by Bohlin et al. (1980). The non-linearity problem, which affects SWP images processed at Goddard Space Flight Center in the period May 22, 1978 to July 7, 1979 and at VILSPA in the period June 14,…
IUE ultra-violet spectrophotometry of 15 galactic Wolf-rayet stars.
Schmutz, W.; Nussbaumer, H.; Willis, A. J. +1 more
Low-resolution IUE ultraviolet spectrophotometry is presented of 15 galactic WR stars, covering most subtypes in the WN and WC sequences. The data are presented both as spectral plots and as tabulations of the observed absolute flux distributions covering the wavelength range of 1150-3090 A. The characteristics of these UV WR spectra are discussed…
Shell and photosphere of OMI ORI E : new observations and improved model.
Groote, D.; Hunger, K.
Phase-dependent IR fluxes in the J, H, K, L, and M bands, together with visual spectrograms and IUE spectra, are used to study the helium-rich star Sigma Ori E. An effective temperature of about 22,500 K is derived, along with an angular diameter of 0.079 milliarcsec, a surface gravity of log g equals 3.85, and a mass of approximately 3 solar mass…
The ultraviolet spectrum of the Crab nebula.
Davidson, K.; Gull, T. R.; Kafatos, M. +6 more
Ultraviolet spectroscopy of the Crab Nebula done by the International Ultraviolet Explorer satellite is described, and an estimate of the carbon abundance is made, noting data reduction to remove spectral defects caused by radiation hits. The important C IV 1549, He II 1640, and semiforbidden C III 1908 emission line intensities were measured and …
Ultraviolet observations of stellar chromospheric activity.
Raymond, J. C.; Dupree, A. K.; Hartmann, L.
A survey is presented of chromospheric and transition region (TR) line emission in late-type stars obtained with the IUE satellite. A wide variation in TR emission (ions formed near T = 100,000 K) at a given position in the H-R diagram is found, contradicting theories that incorporate only acoustic energy generation and deposition. The behavior of…