Supernova explosions within wind-driven bubbles are studied with 2D hydrodynamical calculations. Two different density distributions for the ejecta are considered: (1) a smooth, unfragmented power-law stratification, and (2) a fragmented distribution. As in 1D models, the presence of the shell of interstellar swept-up matter causes the rapid

Deconvolution from wavefront sensing is a new technique of high-resolution imaging through atmospheric turbulence developed at ONERA. The capabilities of the method have been demonstrated during first laboratory experiments. A deconvolution experimental set-up was installed on the 4.2 m William Herschel telescope on La Palma in November 1990. The

The morphological characteristics of corrugations in the disk shapes of the edge-on galaxies NGC 4244 and 5023 are described to determine some of the properties of these features. The corrugations are found to have a 'central' area of high corrugation and wavelike structures of increasing wavelengths emanating from the 'central' zone. If warps have

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This document updates and extends the photographic catalog of selected planetary size comparisons. It utilizes photographs taken by NASA spacecraft to illustrate size comparisons of planets and moons of the solar system. Global views are depicted at the same scale, within each comparison, allowing size relationships to be studied visually.

In this paper we report the results of simultaneous observations, using rapid continuous differential photometry, of the δ Scuti star 63 Her and of a normal main sequence F2V star, HD 155543. These observations, which lasted three weeks, in May-June 1987, were performed at the 1.5 m telescopes of the "Observatorio del Teide", in Tenerife (Spain)