  We study the evolution of the orbit of a planetary companion as the primary
star evolves during the red giant branch phase. Our aim is to determine a
prescription for the capture radius and capture timescales for companions in a
wide range of masses, from planet to star, including the effect of a non
constant f parameter. Our initial results reproduce past findings. According to
our study the mass-loss during the red giant branch does not significantly
affect the semi major axis of the planet and for a 1.5 M star the capture
radius is approximately 300 R or 1.4 AU.
