ASTROPHYSICS: Swallowing Planets

The Swallowing of Planets by Giant Stars

We present simulations of the accretion of a massive planet or brown dwarf by an AGB star. In our scenario, close planets will be engulfed by the star, spiral-in and be dissipated in the “accretion region” located at the bottom of the convective envelope of the star. The deposition of mass and chemical elements in this region will release a large amount of energy that will produce a significant...

ASTRONOMY AND ASTROPHYSICS uvby Photometry of stars with planets

The use of Strömgren uvby photometry is proposed as a simple tool for the estimation of effective temperatures and metallicities in stars discovered to have planets. Previous photometric calibrations are tested with available spectroscopic measurements and their application to stars without high-resolution spectroscopy allowed the determination of metal abundances for 12 additional stars with p...

Dense plasmas in astrophysics: from giant planets to neutron stars

We briefly examine the properties of the dense plasmas characteristic of the interior of giant planets and of the atmospheres of neutron stars. Special attention is devoted to the equation of state of hydrogen and helium at high density and to the effect of magnetic fields on the properties of dense matter. PACS numbers: 05.70.−a, 64.10.+h, 96.30.Kf, 96.30.Mh, 97.60.Jd (Some figures in this art...

Astrophysics.

Using the oscillation frequencies of α Cen A recently discovered by Bouchy & Carrier (2001, 2002), the available astrometric, photometric and spectroscopic data, we tried to improve the calibration of the visual binary system α Cen. With the revisited masses of Pour-baix et al. (2002) we do not succeed to obtain a solution satisfying all the seismic observational constraints. Relaxing the const...

Astrophysics.