For the past 6 years the authors have been measuring the radial velocity of the M-giant component of symbiotic stars with high dispersion echelle spectrographs. The orbital solutions derived from these velocity curves allow the approximate size of the binary to be determined, and also provide insight into the origin of the photometric variations

Solar velocity data collected at Izaña (Tenerife) over the years 1980 - 1985 have been used to search for the 160 minute oscillation. The peculiar behaviour of the ninth harmonic of a day, in amplitude and phase, suggests the existence of a solar signal with a 160.02±0.01 minute period, which can be interpreted as a g-mode.

The radial hydrogen (H2 + HI) distribution in spirals takes two forms: with a density peak at the nucleus or with a circular 'hole' around it. Spectral and photometric properties of selected spirals are examined, and cases of expansion in the circumnuclear gas, as well as ring structures in gas and stars are found. The correlation between absence

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The IRAS Point Source Catalog was cross-correlated with the Lynds Catalog of Dark Clouds to find bright IR sources with 100-micron fluxes higher than their corresponding fluxes at 60 microns. The objective was the detection of new candidates for bipolar molecular outflow sources and/or young embedded PMS stars associated with those clouds. Thirteen

Both linear and nonlinear analysis are used to gain a better understanding of the effects of multi-dimensional transfer of energy by radiation in spatially structured stellar atmospheres. Information on the radiative response of RE (radiative equilibrium) model atmospheres to temperature fluctuations is obtained. Whether or not such perturbed