Toward Detection And Characterization Of Exoplanetary Magnetic Fields Via Low Frequency Radio Observation

Low frequency radio emission from planets is produced by the interaction of energetic charged particles from the planet's ionosphere and/or the solar wind with the planet's magnetic field. The temporal and spectral characteristics and variability of planetary radio emission encode information about a planet's magnetic field strength and morphology, rotation, and interior. This thesis describes three distinct approaches to detecting radio emission from extrasolar planets ( exoplanets). The first is a novel approach using 'big data' and computer aided discovery tools to mine radio survey images for faint radio emission from the location of nearby stars. The flexible approach described in this thesis produced upper limits of rv lOOx Jovian radio flux for a large sample of nearby stars and known exoplanet systems. The sensitivity is sufficient that large radio bursts from nearby stars or planets could have been detected if they took place during the survey observation(s). The framework developed here can be used for automated exoplanet radio emission searches in future radio survey data. The second approach described herein is a blind survey of the nearest Northern hemisphere stars across a broad range of frequencies in order to detect as-yet unknown planets or set tight constraints on radio emission from the stars and possible substellar companions. The survey approach used here is novel because it makes no assumptions about which stars are most likely to host radio emitting planets and it covers frequencies from 30 MHz to 4 GHz. This survey produced a detection of multiple rv50% circularly polarized flares from the M dwarf binary system Ross 614 as well as limits at the lOx Jovian flux level for the remaining stars observed. The limits attained from this survey are the first published at 1-4 GHz for these objects and the only available radio limits for a newly discovered cool (T9) brown dwarf. The limits from this survey place a preliminary constraint on the magnetic field of the brown dwarf at