Influence of Stellar Multiplicity On Planet Formation. III. Adaptive Optics Imaging of Kepler Stars With Gas Giant Planets

TL;DR

This study investigates how stellar companions influence gas giant planet formation around Kepler stars, revealing that close stellar multiplicity suppresses planet formation within 20 AU, while wider separations may enhance it.

Contribution

The paper provides high-resolution AO imaging of Kepler stars, develops methods to confirm stellar companions, and quantifies how stellar multiplicity affects gas giant planet formation.

Findings

Stellar companions within 20 AU suppress gas giant formation.

Multiplicity rate within 20 AU is near zero for planet hosts, much lower than field stars.

Higher multiplicity rate between 20-200 AU for planet hosts compared to field stars.

Abstract

As hundreds of gas giant planets have been discovered, we study how these planets form and evolve in different stellar environments, specifically in multiple stellar systems. In such systems, stellar companions may have a profound influence on gas giant planet formation and evolution via several dynamical effects such as truncation and perturbation. We select 84 Kepler Objects of Interest (KOIs) with gas giant planet candidates. We obtain high-angular resolution images using telescopes with adaptive optics (AO) systems. Together with the AO data, we use archival radial velocity data and dynamical analysis to constrain the presence of stellar companions. We detect 59 stellar companions around 40 KOIs for which we develop methods of testing their physical association. These methods are based on color information and galactic stellar population statistics. We find evidence of suppressive planet formation within 20 AU by comparing stellar multiplicity. The stellar multiplicity rate for planet host stars is 0$^{+5}_{-0}$\% within 20 AU. In comparison, the stellar multiplicity rate is 18\%$\pm$2\% for the control sample, i.e., field stars in the solar neighborhood. The stellar multiplicity rate for planet host stars is 34\%$\pm$8\% for separations between 20 and 200 AU, which is higher than the control sample at 12\%$\pm$2\%. Beyond 200 AU, stellar multiplicity rates are comparable between planet host stars and the control sample. We discuss the implications of the results to gas giant planet formation and evolution.