Transiting planets of intermediate-mass stars

• Applicant: Dr. Eike W. Guenther
• Subject Area: Astrophysics and Astronomy
• Term: from 2014 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 267447025

In contrast to planets of solar-like stars, very little is known about planets of intermediate mass (1.3-2.1 Msun) stars. Although it is well known that intermediate-mass stars can have planets with long orbital periods, it is not know whether they have also have planets with short orbital periods, like solar-like stars. The interesting aspect is that the lifetime of the disks of these stars is half as long as that of lower-mass stars. Thus, if we detect close-in planets of such stars we know the planets must have formed and migrated inwards within this time. We selected transiting planet candidates from the CoRoT-database, which have orbital periods of 4 days or less. For these candidates we already know that there is a transiting object. However, we do not know whether this objects is a low-mass star, a brown dwarf or a planet. Only radial-velocity measurements well tell that. In the previous year, we have obtained spectra with the CAFE-spectrograph at the 2.2m telescope on Calar Alto. We found serval objects with masses in the range between the star and a brown-dwarf, and companions with such low-mass that more spectra are needed in order to determine their nature. We thus applied for more observing time on the same telescope in order to determine the masses of these objects. In parallel to the Calar Alto project, we also obtained observing time at ESO in which we found one brown dwarf and one planet. Once the survey is completed, we will know what the frequency of close-in transiting planets of such stars is, and whether they have on average a higher mass and density than planets of solar-like stars, as predicted by theory.

• DFG Programme: Research Grants