Resolved Debris Disk Emission around Eta Tel: A Young Solar System or Ongoing Planet Formation?
First Author:
Laura Churcher
Email: ljc51 AT ast.cam.ac.uk
University of Cambridge
Institute of Astronomy, University of Cambridge, Madingley Road
Cambridge, CB3 0HA
Coauthors:
Smith, Rachel, University of Cambridge
Wyatt, Mark, Universityof Cambridge
Moerchen, Margaret, University of Florida, Gainesville
Telesco, Charles, University of Florida, Gainesville
Abstract
Over half of the A star members of the 12 Myr-old Beta Pictoris moving group (BPMG) show significant excess emission in the mid-infrared, several million years after the proto-planetary disk is thought to have dispersed. Theoretical models suggest this peak may coincide with the formation of Pluto-sized planetesimals in the disk, stirring smaller bodies into collisional destruction. Here we present resolved mid-infrared imaging with T-ReCS of the disk of Eta Tel (A0V in the BPMG) and consider its implications for the state of planet formation in this system. Modelling indicates that the extension arises from an edge-on disk of radius ~24 AU, but that >50% of the 18 um emission comes from an unresolved dust component at ~4 AU. The radial structure of the Eta Tel debris disk is reminiscent of the asteroid and Kuiper belts in the Solar System, suggesting that this is a young Solar System analogue. However, for an age of 12 Myr, both the radius and dust level of the extended cooler component are also consistent with self-stirring models in which case the hot dust component may arise in massive collisions due to ongoing terrestrial planet formation.
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