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Mapping radio emitting-region on low-mass stars and brown dwarfs

Yu, S.
; 
Doyle, J.G.
; 
Hallinan, G.
; 
MacKinnon, A.L.
Repository DOI
Publication Date
2011-01-01
Keywords
electron-cyclotron maser, auroral kilometric radiation, ultracool dwarf, instability, emission, driven
Type
Article
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Citation
Yu, S. Doyle, J.G.; Hallinan, G.; MacKinnon, A.L. (2011). Mapping radio emitting-region on low-mass stars and brown dwarfs. EPJ Web of Conferences 16 ,
Abstract
Strong magnetic activity in ultracool dwarfs (UCDs, spectral classes later than M7) have emerged from a number of radio observations, including the periodic beams. The highly (up to 100%) circularly polarized nature of the emission point to an effective amplification mechanism of the high-frequency electromagnetic waves - the electron cyclotron maser (ECM) instability. Several anisotropic velocity distibution models of electrons, including the horseshoe distribution, ring shell distribution and the loss-cone distribution, are able to generate the ECM instability. A magnetic-field-aligned electric potential would play an significant role in the ECM process. We are developing a theoretical model in order to simulate ECM and apply this model to map the radio-emitting region on low-mass stars and brown dwarfs.
Funder
Publisher
EDP Sciences
Publisher DOI
10.1051/epjconf/20111606013
Rights
Attribution-NonCommercial-NoDerivs 3.0 Ireland
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Externally hosted open access publications with University of Galway authors (2)