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IUE Spectroscopy of U Cephei during the Mass Flow Outburst of 1986 June
Kondo, Yoji; McCluskey, George E., Jr.; Olson, Edward C.
The interacting Algol-type binary U Cep underwent another of its irregularly occurring transient high-mass flow events during June 1986. For the first time, high-resolution ultraviolet spectroscopy of U Cep during such an event was possible. High-resolution spectra in the far-ultraviolet and near-ultraviolet were obtained with IUE. These spectra s…
Cometary H2 + and solar wind He2+ dynamics across the Halley cometopause
Balsiger, H.; Geiss, J.; Ip, W. -H. +4 more
Two Mass/Charge (M/Q) ≈ 2 distributions were observed by the Giotto Ion Mass Spectrometer/High Energy Range Spectrometer (IMS/HERS) during the encounter with comet Halley. The first, present throughout the encounter, is identified as solar wind He2+. The second, detectable only within ∼6 × 105 km of the nucleus, is identified…
The Atmospheric Eclipse of 31 Cygni in the Ultraviolet
Eaton, Joel A.
Theoretical spectra have been compared with high-dispersion IUE observations for the 1982 atmospheric eclipse of 31 Cyg (B4 V + K4 Ib). Chromospheric column densities, excitation temperatures, turbulence, and ionization are determined. It is found that temperature increases with height in the chromosphere, showing a range 5000 - 14,400K for four l…
Surficial textures of the Galilean satellites
Buratti, B. J.; Nelson, R. M.; Lane, A. L.
Knowledge of the textural characteristics of planetary surfaces is one of the objectives of remote sensing observations. The comparison of accurate photometric measurements with scattering models yields estimates of the compaction state of the optically active portion of the regoliths of airless bodies. We have analysed as a function of solar phas…
Carbon abundance in beta Persei and lambda Tauri.
Cugier, H.; Hardorp, J.
A carbon abundance analysis of two Algol-type stars is performed using IUE archival data released for general use. The primaries of Beta Per and Lambda Tau show carbon abundances equal to log N(C/H) = -3.87 + or - 0.20 and 3.88 + or - 0.20, respectively. The results should be compared with the cosmic value of -3.48 given by Allen (1973). A C-defic…
The Ultraviolet Spectra of M31 Globular Clusters
Cowley, A. P.; Burstein, D.
Ultraviolet spectra of 11 of the brightest globular clusters in M31 show that some exhibit residual flux below 3000 A, greater than that expected from the bright, evolved stars in the cluster. There seems to be no apparent correlation of the strength of this ultraviolet flux with parameters such as metallicity, U-B color, visual magnitude, x-ray e…
The Ionization Structure of Planetary Nebulae. VIII. NGC 6826
Barker, Timothy
Spectrophotometric observations of emission-line intensities over the spectral range 1400 to 1700 A were made in seven positions in the planetary nebulae NGC 6826. The O(++) electron temperature varies little from 8900 K throughout the nebula; the Balmer continuum electron temperature averages 1500 K higher. The wavelength 4267 C II line intensiti…
A differential analysis of UV photospheric lines of OBN and OBC stars.
Lamers, H. J. G. L. M.; de Jager, C.; Wollaert, J. P. M.
The paper presents measurements of the equivalent widths of several photospheric C, N, O, He, Si and Fe lines in the ultra-violet spectra of 55 OBN, OBC and normal supergiants and main-sequence stars. Seventy-two short-wavelength, high-resolution spectrograms obtained with IUE were used. The differences in equivalent widths of OBN and OBC stars re…
On the rotation axis of comet Halley
Keller, H. U.; Thomas, N.
The observations of comet Halley by the Halley Multicolour Camera (HMC) on board the European Space Agency's Giotto spacecraft were supported by an extensive ground-based observational programme using the same filter set1. The intention was to place the transitory but detailed observations of the encounter in the frame of ground-based o…
The long-period semi-detached giant binary system 5 Ceti.
Eaton, Joel A.; Barden, Samuel C.
The binary system 5 Ceti consists of a K3 III star at or near its Roche lobe and a small hot companion best studied in the satellite ultraviolet. The hot radiation source at the secondary star is immersed in the chromosphere of the K giant, and the slight enhancements of a few UV absorption lines at secondary minimum are used to estimate chromosph…