Magnetic Fields at Low Temperatures: Cool Stars, Brown Dwarfs, and (Eventually) Exoplanets
131B Campbell Hall
Peter Williams (Harvard CfA)
The magnetic field of Earth protects its surface from cosmic rays and the solar wind, while that of Jupiter enables powerful aurorae that can be brighter than the Sun at long radio wavelengths. What are the magnetic fields of extrasolar planets like? While direct observational probes are not yet feasible, the groundwork for answering this question is being laid, with the ultimate goal of characterizing magnetic properties across the spectrum of exoplanet types and peering "inside" rocky planets to identify which ones may be geologically active. I will discuss my recent work in this direction, including the detection of periodic auroral radio bursts from a 900-Kelvin T6.5 dwarf, and prospects for the future.