Welcome
This group unites projects with the following objectives: 1) The study of the structure and dynamics of the solar interior. 2) the extension of these studies to other stars, and 3), the search for extrasolar planets with photometric methods.
The unifying aspect of these objectives are their use of high-precision photometry as the major observational method. For the first objective we use the only technique that actually allows the study of stellar interiors: ‘Helioseismology’. Through the detection and study of global pulsation modes of the sun it is possible to infer precisely information about its structure and internal dynamics. This means the determination of the range of the most important physical parameters, from the stellar center up to the surface. The project covers the distinct factors that are needed to achieve the previously mentioned objectives: the instrumental one, in which we worked intensively in the past and still continue so, the observational one, realizing uninterrupted observations across the year within several world-wide networks of helioseismic stations, and having access to data of the GOLF and VIRGO experiments on board of the space mission SOHO, the divers techniques to reduce, analyze and interpret the data, and lastly, the theoretical development of inversion techniques and models of the solar structure and evolution.
The results that were already obtained show that we can obtain information about the Sun with a precision of one in a thousand and have contributed efficiently to the well known problem of the solar neutrinos.
On the other side, it is not surprising that one tries to obtain similar insights about other stars, which constitutes the framework of the discipline known as ‘Asteroseismology’ or stellar seismology. Asteroseismology has progressed tremendously over the past decade, driven by ground-based observations and several satellite missions as CoRoT and Kepler, in which our group is involved. The CoRoT mission has provided data on a few stars showing solar-like oscillations. For the stars observed, the acoustic modes could be unambigously identify and the signature of magnetic activity measured. The launch of Kepler in 2009 marked an important milestone in asteroseismology. We now have continuous observations with longer duration and higher precision, allowing the detection of more modes on many more stars. The rich informationc content in these observations means that the fundamental stellar properties may be measured and the internal structures constrained to levels that would not otherwise be possible.
The method of transits for the search for extrasolar planets consist in the photometric detection of small drops in stellar brightness (and also, in color) when one of a stars planets moves in front of that star that is, between the star and the observer. Actually, this method is the only one that allows the detection of terrestrial sized planets with current technology. Another aspect of this ‘transit method’ is the possibility to perform relatively detailed studies on discovered planets. This technology is similar to the one used in helio and asteroseismic studies, from which it is a logical development to apply our experiences ontained from the former studies. On the other hand, the transit method requires also the development of special detection algorithms to detect the planets and to distinguish their signatures from those of ‘false alarms’.