Transiting exoplanets from the CoRoT space mission III. The spectroscopic transit of CoRoT-Exo-2b with SOPHIE and HARPS

TL;DR

This paper presents spectroscopic observations of the transiting hot Jupiter CoRoT-Exo-2b, analyzing the Rossiter-McLaughlin effect to determine the alignment between the star's spin and the planet's orbit, confirming the planet's nature.

Contribution

It provides the first measurement of the sky-projected spin-orbit angle for CoRoT-Exo-2b using SOPHIE and HARPS spectrographs, and discusses stellar activity effects.

Findings

Sky-projected angle lambda=7.2+-4.5 degrees indicating aligned orbit

Confirmed the planetary nature of CoRoT-Exo-2b

Analyzed stellar activity influence on RM measurements

Abstract

We report on the spectroscopic transit of the massive hot-Jupiter CoRoT-Exo-2b observed with the high-precision spectrographs SOPHIE and HARPS. By modeling the radial velocity anomaly occurring during the transit due to the Rossiter-McLaughlin (RM) effect, we determine the sky-projected angle between the stellar spin and the planetary orbital axis to be close to zero lambda=7.2+-4.5 deg, and we secure the planetary nature of CoRoT-Exo-2b. We discuss the influence of the stellar activity on the RM modeling. Spectral analysis of the parent star from HARPS spectra are presented.