Pineda, John Sebastian (2017) Multiwavelength Characterization of the Brown Dwarf Auroral Phenomenon - Establishing the Nature of the Electrodynamic Engine. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/Z90C4SRW. http://resolver.caltech.edu/CaltechTHESIS:10122016-095646319
Stellar coronal activity has been shown to persist into the low-mass star regime, down to late M-dwarf spectral types. However, there is now an accumulation of evidence suggesting that at the end of the main sequence there is a transition in the nature of the magnetic activity from chromospheric and coronal to planet-like and auroral, from local impulsive heating via flares and MHD wave dissipation to energy dissipation from strong large-scale magnetospheric current systems. In this dissertation, I examine the effects of these processes on the atmospheres of brown dwarfs across multiple different wavebands and investigate the underlying mechanisms powering the electrodynamic engine responsible for auroral emission in brown dwarfs. I conduct observational surveys looking for the emission features of Hα and H3+ as indicative of auroral systems across the ultracool dwarf regime. I further provide a comprehensive view of brown dwarf magnetic activity and auroral phenomena, detailing the various emission processes, and expectations for auroral brown dwarfs. I also initiate a preliminary analysis of the detailed emission features and discuss the constraints imposed on the electrodynamic engine of these objects.
|Item Type:||Thesis (Dissertation (Ph.D.))|
|Subject Keywords:||Brown Dwarfs; Aurorae; Magnetic Activity|
|Degree Grantor:||California Institute of Technology|
|Division:||Physics, Mathematics and Astronomy|
|Thesis Availability:||Public (worldwide access)|
|Defense Date:||14 September 2016|
|Default Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||John Pineda|
|Deposited On:||14 Oct 2016 22:59|
|Last Modified:||14 Oct 2016 23:02|
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