Abstract

A possibility to detect non-thermal radio emission from exoplanets offers a unique, direct way to measure their magnetic fields. For example, time-frequency mapping of radio flares generated by the cyclotron maser mechanism would help constraining the planet’s magnetic field topology and origins. Because planetary magnetic fields mitigate the effects of stellar winds and flares, detecting and characterizing them would obviously inform the investigations of planetary habitability. Similarly, radio characterization of the activity of low-mass stars, in addition to assessing their UV and X-ray emission, represents an important aid in constraining habitability of any close-in planets around them. This is essential in view of the rapid development of large searches for terrestrial-mass planets around M-dwarf stars.

I will discuss the ongoing Arecibo programs to detect flaring radio emission from the coolest brown dwarfs and giant exoplanets, and to monitor radio activity of M-dwarf targets of the upcoming near-infrared, Habitable Planet Finder survey with the Hobby-Eberly Telescope. In particular, I will present the most recent detections of flares from two T-type brown dwarfs, which suggest that the same should be possible for hot, young exoplanets such as the relatively nearby HR8799 system. I will also discuss the results of one year long monitoring of an M9-star, TVLM 513 -46546, used as a proxy for the design of our M-dwarf monitoring project.