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The Upstream Region Foreshock and Bow Shock Wave at Comet p/ Halley from Plasma Electron Measurements
Anderson, K. A.; Reme, H.; Korth, A. +7 more
We survey the plasma electron parameters from a distance 2.7 × 106 km from the comet nucleus to the bow shock wave at about 1.1 × 106 km and somewhat beyond. We describe the features of the electron foreshock lying outside the shock to a distance of about 230,000 km. It is a region of intense solar wind-comet plasma interacti…
Cosmic ray gradients in the outer Galaxy
Wolfendale, A. W.; Mayer, C. J.; Richardson, K. M. +2 more
The release of basic cosmic gamma ray data from the COS B satellite experiment has enabled a more detailed analysis than hitherto of the problem of variations of cosmic ray intensity locally and in the Outer Galaxy. It is found that there is still evidence for a modest cosmic ray gradient, particularly at the highest gamma ray energies where the p…
Different regions of line formation in the envelope of the early emission line star HD 190073.
Ringuelet, A. E.; Rovira, M.; Cidale, L. +1 more
A description is presented of the spectral features that characterize the spectrum of HD 190073 both in the photographic region from about 3600 Å to about 6600 Å, and in the IUE ultraviolet, from about 1150 to about 3200 Å. A number of different types of profiles can be distinguished and this seems to imply that many different "broad" regions of l…
Analysis of the MG II resonance lines in the spectrum of Sirius.
Talavera, A.; Freire Ferrero, R.; Gouttebroze, P.
The atmospheric layers above the photosphere of Sirius A (Alpha CMa, AlV) are analyzed using high-resolution spectra of the Mg II resonance lines obtained with the Copernicus and IUE satellites. The line cores are formed at optical depths so small that an extension of the existing photospheric models for Sirius is necessary. Two tentative sets of …
Far-UV variability of theta CrB in 1985-86 : a progression toward higher velocities.
Doazan, V.; Thomas, R. N.; Rusconi, L. +1 more
New far UV observations of θ CrB obtained with the IUE in 1985 - 1986 are presented. They show that the far UV spectrum of that star has usually continued to exhibit the apparently low excitation state observed from mid-84 to mid-85. However, the C IV resonance lines are occasionally conspicuous and exhibit an even higher outflow velocity than dur…
The ultraviolet gallium stars.
Jaschek, M.; Jaschek, C.
On the basis of IUE low dispersion spectra, the authors define a group of UV peculiar stars in the range of middle and late B-type stars, characterized by strong Ga II λ1414 line. This group has no counterpart in the optical λλ3600 - 4800 range.
Interstellar absorption lines in the spectra of theta-Crateris and 14Canum Venaticorum.
de Boer, K. S.; Grewing, M.; Bianchi, L. +1 more
High-resolution (≡0.2 Å) ultraviolet spectra of the two B9 stars θ Crateris (HD 100889) and 14 Canum Venaticorum (HD 113797) have been obtained with the IUE satellite. Since both are fast rotators interstellar absorption lines can easily be separated from the stellar features allowing a determination of the Mg I, Mg II, Fe II, Si II, and S II colu…
A rotational-state population analysis of the high-resolution IUE observation of CS emission in comet P/Halley
Jackson, W. M.; Prisant, M. G.
The high resolution spectrum of comet P/Halley has been measured in the region of the CS emission. CS in comet Halley is produced by photodissociation of CS2 and subsequently re-excited by broad band solar radiation. An inversion procedure is introduced to extract the rotational population distribution from the dispersed fluorescence sp…
The bright QSO GD 1339.
Kollatschny, W.; Fricke, K. J.; Bues, I. +1 more
Multifrequency observations of the radio-quiet QSO GD 1339 have been obtained using the EXOSAT, IUE, and ESO telescopes. The redshift of GD 1339 is z = 0.116 and its apparent magnitude mv = 15m.2. This bright nearby QSO may be suitable for detailed follow-up studies and as a spectroscopic reference source.
The radial distribution of galactic gamma rays. III - The distribution of cosmic rays in the Galaxy and the CO-H2 calibration.
Strong, A. W.; Hermsen, W.; Lebrun, F. +7 more
High-energy (>70 MeV) gamma-ray observations are compared to H I and CO surveys over more than half of the Milky Way. The kinematics of both H I and CO are used as a distance indicator to determine, in combination with COS-B gamma-ray data, the galacto-centric distribution of the gamma-ray emissivity (the production rate per H atom) for three g…