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The Spectroscopic Orbit of 6-DRACONIS

Reimers, D.; Griffin, R. F.; Eitter, J. J.

6 Dra has long been known to show small variations in radial velocity, and there is photometric and spectroscopic evidence that its spectrum is composite. We show, largely on the basis of a generous number of photoelectric radial velocities mainly obtained at Cambridge and Fick observatories, that the orbit is of mild eccentricity and has a period…

The comet nucleus: ice and dust morphological balances in a production surface of comet P/Halley.

Green, S. F.; McDonnell, J. A. M.; Pankiewicz, G. S. +2 more

Dust-to-gas mass ratios are presented based on in situ measurements of the coma dust and gas distributions of comet P/Halley by the DIDSY, PIA, and NMS experiments aboard the Giotto spacecraft. A relative excess, compared with preflight expectations, of particulates with masses >10^-9kg is observed; if this is representative of the co…

The First UV Spectrum of a Uranian Satellite: IUE Observations of Oberon from 2650-3200 A

Buratti, B. J.; Stern, S. A.; Festou, M. C. +1 more

Using the International Ultraviolet Explorer (IUE) observatory, the first vacuum UV spectrum of Oberon was obtained. The data contain useful information in the spectral range 2650-3200 A. Oberon's UV geometric albedo is found to be flat and essentially featureless with an average value of p(UV) = 0.19 + or - 0.025, and making it possible to extend…

IUE Spectra of the Four Interacting Binary White Dwarf Stars - Am-Canum PG:1346+082 V803-CENTAURI and Gp-Comae - a Comparative Study

Solheim, J. -E.; Ulla, A. M.

This project is part of a world wide cooperation aimed at investigating properties of white dwarf stars to determine their constitution and evolution. The project is based on two recent developments: -The first is the discovery, of pulsational instabilities in some white dwarf stars, giving rise to non-radial pulsations which can be observed as fl…

Galactic gamma — ray sources in the 40-50 MeV range

Li, Ti-Pei; Wu, Mei

A gamma-ray map of the Galaxy in 40-50 MeV reveals, besides the three sources known at higher energies, four additional sources with intensities comparable to that of the Crab.

The orbit of lambda Virginis and other matters

Stickland, D. J.

UVBY photometry of HIPPARCOS stars.

Oblak, E.

Photoelectric data in the uvby system have been obtained for 367 southern stars of the Hipparcos Input Catalogue. Most of the stars are F and G main sequence and fall in the magnitude range V = 9 to 10.

EXOSAT observations of the iron line in CEN X-3

Fabian, A. C.; Tennant, A. F.; Takalo, L. O.

Properties of the iron line in Cen X-3 have been studied, using the gas scintillation proportional counter onboard EXOSAT. The iron line energy is seen to be constant (kT = 6.59 +/- 0.06 keV) over orbital and pulse periods. On the other hand the iron line intensity is seen to vary with both periods. The pulse period variations are sinusoidal, but …

PSR 1820-11: a binary gamma-ray pulsar.

Li, Ti-Pei; Wu, Mei

Significant pulsation structure in the phase distribution of 50 - 6000 MeV gamma-rays from the direction of the binary radio pulsar PSR 1820-11 in the COS-B data was obtained by the folding algorithm. Besides period searches, a spatial analysis was performed and a clear point-like image at the pulsar's position for gamma-rays above 50 MeV was obta…

Astronomy with EXOSAT

White, N. E.

The European Space Agency's X-ray observatory EXOSAT was operational from May 1983 to April 1986 and in that time made 1780 observations of a wide variety of objects including active galactic nuclei, stellar coronae, cataclysmic variables, white dwarfs, X-ray binaries, clusters of galaxies and supernova remnants. The 90hr high earth orbit allowed …