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Magnetic structure in cool stars. VIII. The MG II H and K surface fluxes in relation to the MT Wilson photometric CA II H and K measurements.
Zwaan, C.; Oranje, B. J.
Data from IUE observations of 14 F, G, and K stars of luminosity II-V in the Mg II h + k lines are presented in tables and compared with published Mt. Wilson photometry of the Ca II H + K lines, and empirical relations are derived to facilitate the use of Ca II H + K data in investigating the chromospheric structure of cool stars. The results are …
The ultraviolet spectra of normal elliptical galaxies : a population synthesis approach.
Perola, G. C.; Nesci, R.
Published UV spectra of elliptical galaxies are compared with the results of population syntheses (based on HB stars, accreting white dwarfs in binary systems, or young stars forming in bursts) in an attempt to explain the observed upturn shortward of 200 nm. The results are presented in tables and spectra and discussed in detail. Good agreement i…
UV and optical observations of variability in the WR+compact candidate HD 96548.
Smith, L. J.; Lloyd, C.; Walker, E. N.
The present IUE SWP high resolution spectra of the WR+ compact candidate HD 96548 exhibit significant variability in the P Cygni and emission line profiles. A reanalysis of previously published visible photometry in light of new data shows that all the photometry is periodic, with a period of 5.879 d or its one-day aliases at 0.855 and 1.204 d. Th…
The ultraviolet spectrum of the symbiotic star HM Sge.
Nussbaumer, H.; Mueller, B. E. A.
The authors present IUE fluxes of the symbiotic star HM Sge, extracted from IUE observations made during the years 1978 - 1983. They argue in favour of an accretion disc model. They suggest that the sudden flux increase in He II and the more highly ionized atoms were due to a decrease from a high mass accretion rate, leading to a luminosity above …
An analysis of scattered light in low dispersion IUE spectra.
Clarke, J. T.; Basri, G.; Haisch, B. M.
A detailed numerical simulation of light scattering from the low-resolution grating in the short wavelength spectrograph of the IUE Observatory was developed, in order to quantitatively analyze the effects of scattering on both continuum and line emission spectra. It is found that: (1) the redistribution of light by grating scattering did not appr…
The distribution of the local interstellar medium derived from MG II column densities towards seven cool stars.
Molaro, P.; Franco, M. L.; Beckman, J. E. +2 more
High resolution spectra containing the Mg II h and k resonance doublet have been obtained using the long wavelength spectrometer of IUE, for 7 late-type stars (F0 to G8). In one of these stars, β Hyi, two sharp absorption features were detected against the chromospheric emission cores. Using the study of Crutcher (1982) the authors can employ the …
Gas and star content and spatial distribution in the giant extragalactic H II region TOL 89.
Boksenberg, A.; Durret, F.; Bergeron, J.
Tol 89 is a giant H II region 2.5 kpc in diameter, located in one of the arms of the spiral galaxy NGC 5398. We have observed this object in the Uv with the International Ultraviolet Explorer, and at optical wavelengths with long slit spectrophotometric equipment. The UV spectrum of Tol 89 reveals P Cygni profiles, characteristic of stars with str…
Temporal variations in UV spectra of the red giant C star, TW Hor.
Querci, M.; Querci, F.
The time behavior of ultraviolet emission lines in the cool carbon star TW Hor is discussed. The emission lines were obtained over a three year period using the International Ultraviolet Explorer (IUE) spacecraft in the wavelength range 2100-3300 A. All the lines are found to vary in time (on scales of about one hour to two months) without any app…
Spectroscopy and spectrophotometry of the nova-like system V3885 Sagittarii.
Drechsel, H.; Haug, K.
New optical and UV observations of the novalike variable V3885Sgr are analyzed. The line identifications and radial velocity measurements are presented, and the Balmer, He I, and He II line profiles are investigated. Physical parameters of the system are derived, and spectrophotometric light curves are presented. The continuum flux distribution be…
The Lyman alpha emission in W Ursae Majoris.
Whelan, J. A. J.; Vilhu, O.; Rucinski, S. M.
The paper presents results of reductions of six low resolution IUE-SWP spectra properly exposed at Ly-alpha during one orbital revolution of WUMa, the prototype for late-type contact binaries. Two different methods have been used to eliminate the geocoronal contribution to the emission line. The effect of the interstellar H I absorption has been m…