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Description
We performed a detailed abundance determination in a sample of early-type stars with and without planets via spectral synthesis, searching for a likely relation between lambda Bootis stars and the presence of planets. We found no unique chemical pattern for the group of early-type stars bearing giant planets. However, our results support, in principle, a suggested scenario in which giant planets orbiting pre-main-sequence stars possibly block the dust of the disk and result in a lambda Bootis-like pattern. On the other hand, we do not find a lambda Bootis pattern in different hot-Jupiter planet host stars, which does not support the idea of possible accretion from the winds of hot-Jupiters, recently proposed in the literature. As a result, other mechanisms should account for the presence of the lambda Bootis pattern between main-sequence stars. Finally, we suggest that the formation of planets around lambda Bootis stars, such as HR 8799 and HD 169142, is also possible through the core accretion process and not only gravitational instability.
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