La formación de flujos y nebulosas bipolares es un fenómeno muy común en el Universo, aunque aún se comprenden bastante mal los mecanismos físicos responsables. Un tipo particularmente interesante de objetos que producen flujos bipolares son las estrellas simbióticas. Estas estrellas son sistemas binarios en interacción, con una gigante roja

Structural analysis of S0-Sbc galaxies imaged with HST at near-infrared wavelengths shows many nuclei to be flattened systems with surface brightness comparable to that of the spheroidal bulge component. While standard photometric decomposition would assign that light to the bulge component, its flattened shape and disky isophotes argue for

Ultra-compact nuclear rings (UCNRs) are ring-shaped star-forming regions around galactic nuclei that range in radius from a few to 200 pc. Only a handful are known in the literature, but thanks to the high resolution of HST, we are now able to study their frequency and properties in detail. We have discovered UCNRs in three nearby galaxies. In NGC

It is well known that the temperature structure of ionized interstellar gas departs considerably from homogeneity. This is detected in the form of ``temperature fluctuations'' characterized by a parameter represented as t2. In this paper we present the formalism to check whether these small deviations from the equilibrium temperature are also

Data collected recently by the helioseismic experiments aboard the SOHO spacecraft have allowed the detection of low degree p-modes with increasingly lower order n. In particular, the GOLF experiment is currently able to unambiguously identify low degree modes with frequencies as low as 1.3 mHz. The detection of p-modes with very low frequency ({i