Extrasolar planets and brown dwarfs around A-F type stars V. A planetary system found with HARPS around the F6IV-V star HD 60532

TL;DR

This paper reports the discovery of a two-planet system around the F6V star HD 60532 using HARPS, revealing a potential 3:1 resonance and stellar pulsations, advancing our understanding of planetary systems around early-type stars.

Contribution

First detection of a multi-planet system around an F-type star using high-precision radial velocities, highlighting potential orbital resonance and stellar pulsations.

Findings

Two planets with 1 and 2.5 Mjup masses orbit HD 60532.

Evidence of a possible 3:1 mean-motion resonance.

Detection of high-frequency stellar pulsations.

Abstract

Aims: In the frame of the search for extrasolar planets and brown dwarfs around early-type stars, we present the results obtained for the F-type main-sequence star HD 60532 (F6V) with HARPS. Methods: Using 147 spectra obtained with HARPS at La Silla on a time baseline of two years, we study the radial velocities of this star. Results: HD 60532 radial velocities are periodically variable, and the variations have a Keplerian origin. This star is surrounded by a planetary system of two planets with minimum masses of 1 and 2.5 Mjup and orbital separations of 0.76 and 1.58 AU respectively. We also detect high-frequency, low-amplitude (10 m/s peak-to-peak) pulsations. Dynamical studies of the system point toward a possible 3:1 mean-motion resonance which should be confirmed within the next decade.