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Plasma electron signatures of magnetic connection to the Jovian bow shock: Ulysses observations

Balogh, André; Moldwin, Mark B.; Scime, Earl E. +3 more

Ulysses plasma electron observations of bidirectional and enhanced unidirectional electron heat fluxes within 4500 R_J (0.8 a.u. or 3 months on either side of closest approach) of Jupiter are presented as evidence for the magnetic connection of the spacecraft to the Jovian bow shock. These bursts of suprathermal electrons (> 30 eV) ar…

Tracing the roots of interstellar mid-infrared emission.

Desert, F. -X.; Jenniskens, P.

An attempt is made to link components of the interstellar extinction curve to mid infrared emission of interstellar dust. The IRAS mid-infrared emission has been sought for in the direction to all early type stars for which IUE extinction curves have been published. In 44 lines of sight we were able to obtain well defined colours. By comparing the…

Ultraviolet observations of the circumstellar envelope of alpha1 HER in the line of sight of alpha2 Her.

Reimers, D.; Thiering, I.

We establish an empirical model of the circumstellar envelope of the red giant α¹ Her, using spectroscopic UV and optical observations of its visual binary companion α² Her. In particular, we obtained high-resolution IUE long wavelength spectra of α² Her, in which for the first time α¹ Her could be exclu…

Coordinated UV-optical observations of quasars : the evolution of the Lyman absorption.

Cristiani, S.; Giallongo, E.; Buson, L. M. +2 more

The average flux decrement shortward the Lyα emission, due to the well-known "forest" of absorptions, has been measured in the spectra of 8 quasars. Quasi-simultaneous optical and IUE observations of the two low redshift quasars PKS 0637-75 (z = 0.654) and MC 1104+16 (z = 0.632) have been carried out, obtaining relatively high S/N, spectrophotomet…

The Ulysses Cosmic Ray Isotope Experiment II: Source Abundances of Ne, Mg and Si Derived from High Resolution Measurements

Simpson, J.; Connell, J.

A Spectral Study of Four X-Ray--selected BL Lacertae Objects with EXOSAT

Maraschi, L.; Tagliaferri, G.; Treves, A. +2 more

We present new EXOSAT spectral results for four X-ray-selected BL Lac objects (H0323+022, H0414+009, H1426+428, and H1722+ 119). The data were retrieved from the EXOSAT data base. A spectral analysis was performed on the overall low-energy plus medium-energy distributions, which were modeled with a single, absorbed power law. In one case (H1426+42…

Rotational modulation and flares on the RS Canum Venaticorum binary II Pagasi in July/September 1990 : spots and flares on II Peg.

Doyle, J. G.; Mathioudakis, M.; Avgoloupis, S. +3 more

During ultraviolet spectroscopic observations of the RS CVn star II Peg in September 1990 a long duration (greater than or = 3 hrs.) flare was observed. During the early stage of the event, a feature at 1354 A was present, however, within the spectral resolution of the data it is not possible to identify this line. A contribution from the hot coro…

A Determination of the Basic Atmospheric Parameters of phi Cassiopeiae

Rosenzweig, Patricia; Anderson, Lawrence

By constructing non-LTE spherical model atmospheres, we have calculated a theoretical distribution of the emergent radiation that best matches the observed distribution of the supergiant Phi Cas, and so derived its effective temperature, surface gravity, and radius. Since Phi Cas is very likely a member of the open cluster NGC 457, we made extinct…

Ultraviolet and Optical Studies of Binaries with Luminous Cool Primaries and Hot Companions. IV. Further IUE Detections

Parsons, Sidney B.; Ake, Thomas B.

We have obtained IUE spectra for 31 middle and late-type giant and supergiant stars whose TD-1 fluxes or ground-based spectra indicate the presence of a hot component, or whose radial velocities indicate an unseen component. Stellar components earlier than type F1 were detected in 22 cases. While 20 of the hot secondaries are seen weakly in optica…

Detection of Far-Ultraviolet High-Excitation Line Emission and Lyman- beta Absorption in the Gravitational Lens Q0957+561

Kondo, Y.; Bruhweiler, F. C.; Michalitsianos, A. G. +7 more

Test runs with a new data processing software system on archival spectra obtained by the International Ultraviolet Explorer (IUE) reveal high-excitation emission lines in the gravitationally lensed binary quasar 0957+561. The lines of O VI λλ1031,1037 and S VI λ2933,945 are readily seen in a single 390 minute, low-dispersion IUE exposure, when cal…