The SEEDS Direct Imaging Survey for Planets and Scattered Dust Emission in Debris Disk Systems

TL;DR

This survey uses high-contrast imaging to study debris disks with gaps around young stars, aiming to detect planets responsible for disk structures, and finds such giant planets are less common than previously thought.

Contribution

First direct imaging survey targeting debris disks with gaps, providing constraints on the frequency and mass of planets shaping these disks.

Findings

Five disks spatially resolved

Faint point sources mostly not bound companions

Giant planets like beta Pic b are less than 15-30% in occurrence

Abstract

Debris disks around young main-sequence stars often have gaps and cavities which for a long time have been interpreted as possibly being caused by planets. In recent years, several giant planet discoveries have been made in systems hosting disks of precisely this nature, further implying that interactions with planets could be a common cause of such disk structures. As part of the SEEDS high-contrast imaging survey, we are surveying a population of debris disk-hosting stars with gaps and cavities implied by their spectral energy distributions, in order to attempt to spatially resolve the disk as well as to detect any planets that may be responsible for the disk structure. Here we report on intermediate results from this survey. Five debris disks have been spatially resolved, and a number of faint point sources have been discovered, most of which have been tested for common proper motion, which in each case has excluded physical companionship with the target stars. From the detection limits of the 50 targets that have been observed, we find that beta Pic b-like planets (~10 Mjup planets around G--A-type stars) near the gap edges are less frequent than 15--30%, implying that if giant planets are the dominant cause of these wide (27 AU on average) gaps, they are generally less massive than beta Pic b.