A debris disk around the planet-hosting M-star GJ 581 spatially resolved with Herschel
Publication date: 12 November 2012
Authors: Lestrade, J.F., et al.
Journal: Astronomy & Astrophysics
Debris disks have been found primarily around intermediate and solar mass stars (spectral types A-K) but rarely around low mass M-type stars. We have spatially resolved a debris disk around the remarkable M3-type star GJ 581 hosting multiple planets using deep PACS images at 70, 100 and 160 micron as part of the DEBRIS Program on the Herschel Space Observatory. This is the second spatially resolved debris disk found around an M-type star, after the one surrounding the young star AU Mic (12 Myr). However, GJ 581 is much older (2-8 Gyr), and is X-ray quiet in the ROSAT data. We fit an axisymmetric model of the disk to the three PACS images and found that the best fit model is for a disk extending radially from 25 ± 12 AU to more than 60 AU. Such a cold disk is reminiscent of the Kuiper Belt but it surrounds a low mass star (0.3 MSun) and its fractional dust luminosity Ldust/L*