Welcome to the site of the
IAC group on Solar and Stellar Seismology and Extrasolar planet searches.
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. However, the acquisition of spectra of oscillation
modes in other stars is very difficult and depends much on the stellar type under study. Obtaining information about the internal
structure, the evolution and dynamics of main-sequence stars requires instrumental techniques and observational strategies that
are presently still at the limits of their capabilities. This project constitutes therefore a difficult apprenticeship in all
aspects, be they of theoretical (stellar modeling) or of instrumental or observational nature (robotic observing networks,
future space telescopes, etc.)
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 t
echnology is similar to the one used in helio- and asteroseismic studies, from which it is a logical development to apply our
experiences gained from the former studies. On the other hand, this 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’.
Last modification 1/06/2004
