Progress report on the BEBOP search for circumbinary planets with radial velocities

TL;DR

The BEBOP survey uses radial velocities to detect circumbinary planets, reporting the first such planet via RV and exploring the population's characteristics and detection challenges.

Contribution

This study presents the first circumbinary planet detected through radial velocity and compares RV findings with transit discoveries, suggesting a possible population of inflated planets.

Findings

First circumbinary planet detected in radial velocity (BEBOP-1c)

Potential population of inflated planets near binaries

Radial velocity detection is challenging for certain planet types

Abstract

The BEBOP (Binaries Escorted By Orbiting Planets) survey is a search for circumbinary planets using the radial velocity spectrographs HARPS and SOPHIE, currently focusing on single-lined binaries with a mass ratio $<0.3$. Circumbinary systems are an important testing ground for planet formation theories as the dynamically complex influence of the binary makes planet formation and survival more difficult. Here we present the results of the survey so far including: confirmed planets such as BEBOP-1c the first circumbinary planet detected in radial velocity; the status of our observations; and preliminary occurrence rates. We compare the early results of the radial velocity survey to the population of circumbinary planets discovered in transit, and suggest that there may be a population of inflated planets close to the inner binary which are detectable in transit but more difficult in radial velocity. Using time-lag tidal theory, we show that this inflation is unlikely caused by tides.