Search Publications
The ultraviolet IUE spectrum of the population II horizontal-branch Astar HD 109995.
Leckrone, D. S.; Adelman, S. J.
Eight SWP and six LWP high dispersion IUE images of the field horizontal-branch A star HD 109995 have been averaged to increase the signal-to-noise ratio. The line density in the ultraviolet is greater than that of the optical region, but less than that of comparable Population I A stars. Many of the identified lines are those of Fe II. Lines of C…
Lyman-alpha emission from low dispersion IUE spectra
Catalano, S.; Bruno, M.; Marilli, E.
In spite of its importance as cooling mechanism of the chromosphere of late type stars, the hydrogen Lyman-alpha line has been neglected in most IUE programmes The high geocoronal background and the saturation often seen in the stellar emission peak are the major problems that prevent accurate determination of the Lyman alpha flux.
We have de…In-flight analysis of IUE cross-disperser scattered light
Feldman, P. D.
The scattered light properties of the IUE (International Ultraviolet Explorer) cross-disperser gratings are investigated using in-flight data of the emission spectrum of Comet Bradfield (1979X). The scattering function in the vicinity of H I Lyman alpha at 1216 angstroms is found to be significantly lower than that derived from either the laborato…
X-ray, UV, optical and radio observations of the visual binary 53 AQR
Pasquini, L.; Monsignori-Fossi, B. C.; Pallavicini, R. +1 more
The authors present optical (ESO), ultraviolet (IUE), X-ray (EXOSAT) and radio (VLA) observations of the visual binary 53 Aquarii. They show that the two components of the system can be used to infer the properties of the Sun at a much earlier epoch.
Coronal models of late-type stars observed with EXOSAT
Monsignori-Fossi, B. C.; Landini, M.; Pallavicini, R. +1 more
Differential emission measure distributions for transition region and corona able to reproduce X-ray and UV emission are investigated. The EXOSAT, EINSTEIN and IUE data for the solar type star K Cet are analyzed. A multitemperature differential emission measure distribution gives a satisfactory fit of the data.
Halley's Confounding Fireworks
Kerr, Richard A.
The intensive worldwide campaign of observations of Halley's Comet repeatedly yielded data, particularly imagery, of sudden outbursts from the Comet. IUE data for Dec. 24, 1985 showed a brightness increase in the central coma by a factor of 2-3 over a 1-2 day period, followed shortly thereafter by spectra indicating a surge of ionized CO2 150,000 …
IUE observations of neutral hydrogen and deuterium in the local interstellar medium.
Moos, H. W.; Murthy, J.; Linsky, J. L. +4 more
Small-aperture, high-dispersion IUE spectra have been obtained of seven late-type stars that, in general, confirm previous Copernicus results concerning the distribution of hydrogen and deuterium in the local interstellar medium. In addition, the IUE Ly α spectra of Altair, and of the α Cen components, suggest that multiple velocity components exi…
Empirical Constraints on the Outer Atmospheres of Late-Type Giant Stars with IUE
Judge, P. G.
Useful constraints on the outer atmospheric structure of late-type giant stars can be obtained using emission lines observed with the IUE satellite if all important processes in the atomic excitation calculations are included. Carpenter et al. (1985) did not include such effects, and therefore overestimated the geometric extent of the emission reg…
The Giotto experiments
Reinhard, R.
Design and performance features of the scientific instruments carried on the Giotto spacecraft are described. The instruments were selected to meet the basic mission goals: characterize the elemental and isotopic composition of volatile components of the cometary coma and the physical processes and chemical reactions in the cometary atmosphere and…
Coronal X-ray temperatures from Einstein and EXOSAT observations
Schmitt, J. H. M. M.; Monsignori-Fossi, B. C.; Pallavicini, R. +1 more
Spectral analysis of coronal X-ray emission from stars observed with both the Einstein and EXOSAT Observatories is presented. Using computer codes developed by Raymond and Smith /1/ and Landini and Fossi /2/ to calculate the X-ray emission from optically thin plasma in collisional equilibrium we find that the derived coronal parameters depend only…