We examine the influence of non-adiabatic effects on the modes of an isothermal stratified magnetic atmosphere. We present new solutions for magneto-acoustic-gravity (or MAG) waves in the presence of a radiative heat exchange based on Newton's law of cooling. An analytic expression for the dispersion relation is derived, which allows the effect of

We examine the impact of discrete numbers of stars in stellar populations on the results of Chemical Evolution Models. We explore the resulting dispersion in the true yields and their possible relation with the dispersion in observational data based on a Simple Closed-Box model. In this framework we find that the dispersion is larger for the less

We have pursued two different methods to analyze the old stellar population near the Galactic plane, using data from the 2MASS survey. The first method is based on the isolation of the red clump giant population in the color-magnitude diagrams and the inversion of its star counts to obtain directly the density distribution along the line of sight

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We describe the Teide Imaging MEteor System (TIMES), a fully automatic experiment consisting of two fixed image-intensified video cameras which are operated from Teide Observatory (Tenerife, Spain). A second station equipped with an identical system is located in Maspalomas (Gran Canaria, Spain). TIMES has been designed to work with the MetRec

We present deep broadband R and narrowband Hα images of Stephan's Quintet. The observations in the R band show that the diffuse halo of Stephan's Quintet is larger than previously thought and extends out to NGC 7320C. However, we have not found emission connecting NGC 7331 and NGC 7320 to R~26.7 mag arcsec-2 (at more than a 3 σ level), so there is