Brown Dwarf Disks in the Spitzer Era


First Author:
Aleks Scholz
Email: as110 AT st-andrews.ac.uk
SUPA, University of St. Andrews
North Haugh, School of Physics & Astronomy
St. Andrews, KY169SS, United Kingdom
Coauthors:
Jayawardhana, Ray, University of Toronto
Wood, Kenneth, University of St. Andrews
Meeus, Gwendolyn, Astronomisches Institut Potsdam
Xu, Xiaoying, University of Arizona
Damjanov, Ivana, University of Toronto
Stelzer, Beate, Osservatorio Astronomico di Palermo
Eisloeffel, Jochen, Thueringer Landessternwarte Tautenburg

Abstract
Young brown dwarfs share many characteristics with T Tauri stars. Specifically, many of them exhibit excess emission at infrared wavelengths, indicating the presence of dusty disks. Investigating the properties and evolution of these disks by analysing their SEDs is a useful probe for some fundamental problems in star formation theory, and additionally allows us to study the processes of grain and planetesimal growth in an extreme case, constraining the efficiency and universality of planet formation. Over the last few years, sensitive observations with Spitzer have dramatically improved our knowledge about substellar disks. Spitzer data has been used to infer disk frequencies among young brown dwarfs, indicating that disk lifetimes in the substellar regime may be longer than for solar-mass stars. Dust settling and grain growth, signposts of the early stages of planet formation, are found in brown dwarf disks as well. Furthermore, Spitzer has made it possible to detect disks down to objects masses of 8-10 Mjup - at the very bottom of the Initial Mass Function. In this contribution, I will summarise these findings and provide a comprehensive, up to date overview of Spitzer observations for brown dwarf disks.

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