In the circumnuclear zones of the disks of some spirals there is an absence of neutral interstellar hydrogen. A model is devised in which gaseous outflow is sustained by the combined action of massive stars in these zones. The energy requirement, which implies driving out the gas against gravity, can be satisfied if 10 percent or more of the gas

Analysis of solar velocity data obtained at Izaña (Tenerife) over the years 1981 - 1985, has shown the existence of significant signals in the frequency range 25 - 125 μHz. Several ways of analyzing the data have been used in order to interpret these as solar internal gravity modes of degree l ≤ 3.

Photometric observations of some Ap stars with a 50 cm telescope have been carried out at Izaña (Tenerife) in February 1986. The stars observed were, generally, magnetic-cool Ap stars. A search for global oscillations in the range 3 to 15 minutes has been undertaken and they seem to be present in some of the stars observed.

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Selecting stars with previously measured or estimated rotational periods the authors measured Li equivalent widths in 8 stars of the Hyades late main sequence. Plotting log N(Li) against Rossby number the authors can separate the effects of temperature and rotation. They find for stars later than F8 increased depletion with longer period, at

The authors study the application of the phase retrieval algorithm suggested by Walker (1982) to 1-D short-exposure images obtained by infrared stellar speckle interferometry. To verify its performance, the algorithm has been tested previously with 1-D computer simulated speckle images.