Solar cycle variations on the power and frequencies of the low l p-mode solar acoustic oscillations are investigated using an extensive set of observations obtained at Observatorio del Teide (Izaña, Tenerife). The radial velocity of integrated sunlight has been monitored, by means of a resonant scattering spectrophotometer, at several epochs

Preliminary results are presented of spectroscopic analysis of ten young stars in OB associations using high resolution spectra and NLTE calculations. From the known distances the stellar masses are derived. The comparison with evolutionary tracks indicates a possible discrepancy between the masses and enhanced helium abundances derived from the

The measurement of frequencies, linewidths, and splittings of low degree solar p-modes is a difficult task due, firstly, to time scales involved and, secondly, to the spurious presence of side lobes when data is not collected continuously. However, a long set of observations have been obtained at Observatorio del Teide: a total of 52 months of data

An updated review on theoretical research on the role of magnetic fields in prominences is presented. It is concluded that the theory of the Hanle effect has reached a sufficient degree of sophistication and provides a reliable method for measuring the vector magnetic field. For optically thin lines, insensitive to depolarizing collisions, the

High-speed photometric techniques have been found useful as a way to study the acoustic mode signature in low main sequence stars. In this work, the discovery of solar-like oscillations associated to the presence of acoustic modes of pulsation in the F2V star HD155543, located outside of the instability strip, is reported. This finding has been

During a spectroscopic survey of IRAS sources with infrared colours similar to those in planetary nebulae, IRAS 06518-1041 revealed itself as a possible novalike object. The spectrum of IRAS 06518 - 1041, which is shown in Figure 1, presents strong and broad hydrogen Balmer lines together with broad permitted lines of He and C. This spectrum also