Extrasolar planets and brown dwarfs around A-F type stars. I. Performances of radial velocity measurements, first analyses of variations

TL;DR

This paper introduces a new radial velocity measurement method tailored for A-F type stars, demonstrating its effectiveness through simulations and observations, including planet detection and binary identification.

Contribution

The paper presents a novel radial velocity measurement technique for A-F stars, enabling detection of planets and brown dwarfs around these stars, expanding the scope of stellar mass studies.

Findings

Successful detection of a planet around HD 120136 (Tau Boo).

Binary detection in HD 48097 despite high stellar rotation.

Method shows potential for studying planetary systems around A-F stars.

Abstract

We present the performances of a radial velocity measurement method that we developed for A-F type stars. These perfomances are evaluated through an extensive set of simulations, together with actual radial velocity observations of such stars using the ELODIE and HARPS spectrographs. We report the case of stars constant in radial velocity, the example of a binary detection on HD 48097 (an A2V star, with vsini equal to 90 km/s) and a confirmation of the existence of a 3.9 MJup planet orbiting around HD 120136 (Tau Boo). The instability strip problem is also discussed. We show that with this method, it is in principle possible to detect planets and brown dwarfs around A-F type stars, thus allowing further study of the impact of stellar masses on planetary system formation over a wider range of stellar masses than is currently done.