Resolved Millimeter-Wavelength Observations of Debris Disks around Solar-Type Stars

TL;DR

This study uses millimeter-wavelength observations to spatially resolve debris disks around nearby solar-type stars, revealing their structure and properties, and comparing them to the Solar System's Kuiper Belt.

Contribution

First spatially resolved millimeter observations of debris disks around five nearby solar-type stars, providing new insights into their structure and grain properties.

Findings

Disks have radii and widths similar to scaled-up Kuiper Belt.

Grain sizes are close to blowout size, indicating small dust particles.

Disks are consistent with axisymmetric dust distributions.

Abstract

The presence of debris disks around young main sequence stars hints at the existence and structure of planetary systems. Millimeter-wavelength observations probe large grains that trace the location of planetesimal belts. The FEPS (Formation and Evolution of Planetary Systems) $Spitzer$ Legacy survey of nearby young solar analogues yielded a sample of five debris disk-hosting stars with millimeter flux suitable for interferometric follow-up. We present observations with the Submillimeter Array (SMA) and the Combined Array for Research in Millimeter-wave Astronomy (CARMA) at ~2" resolution that spatially resolve the debris disks around these nearby ($d\sim$50 pc) stars. Two of the five disks (HD 377, HD 8907) are spatially resolved for the first time and one (HD 104860) is resolved at millimeter wavelengths for the first time. We combine our new observations with archival SMA and Atacama Large Millimeter/Submillimeter Array (ALMA) data to enable a uniform analysis of the full five-object sample. We simultaneously model the broad-band photometric data and resolved millimeter visibilities to constrain the dust temperatures and disk morphologies, and perform an MCMC analysis to fit for basic structural parameters. We find that the radii and widths of the cold outer belts exhibit properties consistent with scaled-up versions of the Solar System's Kuiper Belt. All the disks exhibit characteristic grain sizes comparable to the blowout size, and all the resolved observations of emission from large dust grains are consistent with an axisymmetric dust distribution to within the uncertainties. These results are consistent with comparable studies carried out at infrared wavelengths.