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IUE observations of two elliptical galaxies : NGC 3379 and NGC 4472.
Capaccioli, M.; Oke, J. B.; Bertola, F.
The International Ultraviolet Explorer observations of the nuclei of the elliptical galaxies NGC 3379 and NGC 4472 show that the flux drops rapidly with decreasing wavelength until about 2300 A, below which the flux increases rapidly. The hot UV component of the radiation can be approximately represented by a blackbody at 30,000 K. The spectra of …
On the relationship between coronae and mass loss in late-type stars.
Raymond, J. C.; Dupree, A. K.; Hartmann, L.
High-dispersion spectra taken with the IUE are used to examine the temperature stratification of the wind of the hybrid atmosphere star Alpha TrA (K4 II). C IV emission is shown to have a line width of 150-200 km/s, with Si III and C III exhibiting 100 km/s widths. It is suggested that the line widths reflect wind expansion, with C IV formed in an…
Concerning the Wolf-rayet and other luminous early-type stars.
Underhill, A. B.
Effective temperatures, radii, and luminosities were determined from S2/68, ANS, UBV, and uvby photometry for four B0/B1 supergiants, four O4 stars, and four WN7/WN8 stars as well as for four test stars having spectral types between B1.5 V and 09 V and five stars with known angular diameters and effective temperatures. The effective temperatures o…
Ultraviolet extinction in the Small Magellanic Cloud.
Ferlet, R.; Lequeux, J.; Prevot, L. +2 more
The considered investigation is concerned with the determination of the UV extinction curve in the Galaxy on the basis of the spectra of stars in the SMC obtained with the aid of the International Ultraviolet Explorer. The determination rests on the comparison of the observed spectral energy distribution of pairs of similar stars with different ex…
On the origin and distribution of C IV and SI IV ions in the neighboring interstellar medium.
York, D. G.; Cowie, L. L.; Taylor, W.
IUE spectrometer observational data are reported on the C IV, Si IV, and N V absorption lines in 46 distant stars at FWHM resolution of 30 km/sec. A simple analytic theory is given for these contributions, including the effects of ionization by a soft X-ray background. While for some of the most distant field stars a photoionized contribution may …
Mass loss from O subdwarfs.
Kudritzki, R. P.; Hamann, W. -R.; Gruschinske, J. +1 more
The P Cygni profiles are reproduced by comoving frame calculations, and a determination is made of the wind parameters. Lower limits of mass loss for these stars (HD 49798 and HD 128220 B) are derived, and upper limits for all four objects are estimated on the basis of general considerations. The empirical results are compared with the available t…
The ultraviolet spectrum of the O-type subdwarf HD 49798.
Kondo, Y.; McCluskey, G. E.; Bruhweiler, F. C.
The O-type subdwarf (O6p) single-lined spectroscopic binary HD 49798, with an orbital period of 1.5477 d, has been observed by the International Ultraviolet Explorer satellite, to aid in analyses of O type photospheres. Four high resolution (0.1A) spectra are found in the far-ultraviolet region, and two high resolution (0.2A) spectra are found in …
Water production models for comet Bradfield /1979 X/
Feldman, P. D.; A'Hearn, M. F.; Weaver, H. A. +1 more
Whipple (1950, 1951) has proposed that water might be the dominant volatile constituent of the cometary nucleus. The considered investigation is concerned with the clues which observations of the cometary coma provide regarding the parents of the dominant observed coma species. In the early part of 1980, comet Bradfield (1979 X) was observed with …
Ultraviolet emission of the VELA supernova remnant and the Cygnus Loop
Raymond, J. C.; Dupree, A. K.; Black, J. H. +1 more
Ultraviolet emission spectra of several filaments in the Vela supernova remnant and the Cygnus Loop are compared with theoretical models of radiative shocks. Shock velocities range from 85 to 130 km/s. Little or no grain depletion is apparent. Several of the observed filaments deviate from the steady-flow models in the sense that much of the photo…
Observations and models of H 2252-035.
Jones, D. H. P.; Pringle, J. E.; Hassall, B. J. M. +7 more
The paper presents photometric, spectroscopic, and spectrophotometric observations of H2252-035 over the wavelength range 1200-22,000 A made in 1980. The continuum is well represented by a blackbody of 12,500 K over most of this range. The infrared points (JHK) show evidence for a slightly cooler contribution. There is a significant excess at wave…