Nuno C. Santos
CAUP

Abstract
In this talk we will present a brief review of possible stellar intrinsic  sources of radial-velocity noise. We will then show a few examples where  stable periodic radial-velocity signals are observed, and whose origin is  not planetary, but due to the presence of dark spots or stellar blends. In  some of the examples, a second signal, induced by a the presence of a  planet, is also observed. We then focus in the study case of a recently  announced planet orbiting the classical T Tauri star TW Hya. We will  discuss a series observations, diagnostics, and tests used to understand  the origin of the observed radial-velocity signal.

2008 October 15, 13:30

IA/U.Porto
Centro de Astrofísica da Universidade do Porto (Auditorium)
Rua das Estrelas, 4150-762 Porto