Uncovering Circumbinary Planetary Architectural Properties from Selection Biases

Abstract

The new discoveries of circumbinary planetary systems shed light on the understanding of planetary system formation. Learning the architectural properties of these systems is essential for constraining the different formation mechanisms. We first revisit the stability limit of circumbinary planets. Next, we focus on eclipsing stellar binaries and obtain an analytical expression for the transit probability in a realistic setting, where finite observation period and planetary orbital precession are included. Then, understanding of the architectural properties of the currently observed transiting systems is refined, based on Bayesian analysis and a series of hypothesis tests. We find 1) it is not a selection bias that the innermost planets reside near the stability limit for eight of the nine observed systems, and this is consistent with a log uniform distribution of the planetary semi-major axis; 2) it is not a selection bias that the planetary and stellar orbits are nearly coplanar ($\lesssim 3^{\circ }$), and this together with previous studies may imply an occurrence rate of circumbinary planets similar to that of single star systems; 3) the dominance of observed circumbinary systems with only one transiting planet may be caused by selection effects; 4) formation mechanisms involving Lidov-Kozai oscillations, which may produce misalignment and large separation between planet and stellar binaries, are consistent with the lack of transiting circumbinary planets around short-period stellar binaries, in agreement with previous studies. As a consequence of 4), eclipse timing variations may better suit the detection of planets in such configurations.

18 pages, 13 figures. Accepted for publication in ApJ

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Cited by in corpus (21)

• TOI-1338: TESS' First Transiting Circumbinary Planet
• Inclination Evolution of Protoplanetary Disks Around Eccentric Binaries
• The BEBOP radial-velocity survey for circumbinary planets I. Eight years of CORALIE observations of 47 single-line eclipsing binaries and abundance constraints on the masses of circumbinary planets
• Kepler-1661 b: A Neptune-sized Kepler Transiting Circumbinary Planet around a Grazing Eclipsing Binary
• Circumbinary planets II - when transits come and go
• Polar planets around highly eccentric binaries are the most stable
• Instabilities in Multi-Planet Circumbinary Systems
• The Architecture of the GW Ori Young Triple Star System and Its Disk: Dynamical Masses, Mutual Inclinations, and Recurrent Eclipses
• Circumbinary discs with radiative cooling and embedded planets
• Distinguishing Polar and Co-planar Circumbinary Exoplanets by Eclipsing Timing Variations
• The binary mass ratios of circumbinary planet hosts
• A radial limit on polar circumbinary orbits from general relativity
• Terrestrial planet formation in a circumbinary disc around a coplanar binary
• Sculpting the circumbinary planet size distribution through resonant interactions with companion planets
• A Pluto--Charon Sonata: Dynamical Limits on the Masses of the Small Satellites
• Effects of Flux Variation on the Surface Temperatures of Earth-like Circumbinary Planets
• Could there be an undetected inner planet near the stability limit in Kepler-1647?
• Multiple Transits during a Single Conjunction: Identifying Transiting Circumbinary Planetary Candidates from TESS
• The First Eclipsing Binary Catalogue from the MOA-II database
• Tidal evolution of circumbinary systems with arbitrary eccentricities: applications for Kepler systems
• Secular Dynamics of Multiplanetary Circumbinary Systems