The debris disk around gamma Doradus resolved with Herschel

TL;DR

This study uses Herschel observations to resolve and model the debris disk around gamma Doradus, revealing a broad dust distribution and possible configurations, with implications for planet location.

Contribution

First detailed Herschel imaging of gamma Doradus debris disk, modeling its structure and constraining potential planet regions.

Findings

Disk is well-resolved at multiple wavelengths.

Two possible dust configurations fit the data.

Inner planet region likely within ~55 AU.

Abstract

We present observations of the debris disk around gamma Doradus, an F1V star, from the Herschel Key Programme DEBRIS (Disc Emission via Bias-free Reconnaissance in the Infrared/Submillimetre). The disk is well-resolved at 70, 100 and 160 micron, resolved along its major axis at 250 micron, detected but not resolved at 350 micron, and confused with a background source at 500 micron. It is one of our best resolved targets and we find it to have a radially broad dust distribution. The modelling of the resolved images cannot distinguish between two configurations: an arrangement of a warm inner ring at several AU (best-fit 4 AU) and a cool outer belt extending from ~55 to 400 AU or an arrangement of two cool, narrow rings at ~70 AU and ~190 AU. This suggests that any configuration between these two is also possible. Both models have a total fractional luminosity of ~10^{-5} and are consistent with the disk being aligned with the stellar equator. The inner edge of either possible configuration suggests that the most likely region to find planets in this system would be within ~55 AU of the star. A transient event is not needed to explain the warm dust's fractional luminosity.