Investigation of the Key Parameters in the Process of Extrasolar Planet Formation around Intermediate-Mass G-K Giant Stars

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This project will expand the survey for searching for extrasolar planets around G–K giants via the precise RV technique that was started in February 2004 at TLS using the 2m Alfred Jensch telescope. To date there are more than 400 extrasolar planets in orbit around other stars than our Sun. However, the host stars span a narrow mass range covered by the spectral types F8–K1, i.e. stars having nearly 1 Mסּ. We know therefore little about how planet formation depends on the mass of the star, particularly for intermediate stars. Early-type stars are difficult targets for RV searches due to the few lines that are broadened by rapid rotation rates. On the other hand, stars that have evolved off the MS have a large number of suitable narrow due to cooler temperatures and slower rotation rates. Thus we propose to expand the initial Tautenburg sample of 62 G–K stars to 300–500 stars. Moreover to the RV measurements we will determine accurate atmospheric parameters such as Teff, g und [Fe/H] for each star. These are important not only for isochrone fitting for the determination of the stellar mass, but also to search for any correlations of properties of the host star (e.g. [Fe/H]) with the frequency and characteristics of the extrasolar planets.