Name/Affiliation: Jackie Villadsen (California Institute of Technology)
Exploring a Threat to Foreign Worlds: Detecting Coronal Mass Ejections on Nearby Stars
Coronal mass ejections (CMEs) likely play a significant role in the mass loss from active stars, and may significantly affect exoplanetary magnetospheres and atmospheres. However, there have been no definitive detections of CMEs outside our own solar system. Broadband dynamic spectroscopy has long been used to study coherent radio emission associated with solar CMEs (known as Type II bursts), but such emission has not been detected from other stars. Type II bursts sweep downwards in frequency on timescales of tens of minutes, tracing the motion of a CME outwards through the stellar atmosphere into progressively lower plasma densities. I will present JVLA observations of UV Ceti showing two Type II-like radio bursts, which sweep upwards in frequency. We interpret these bursts as either bulk plasma motion downwards in the stellar atmosphere or polar radiation modulated by rotation. I will also present plans for the Starburst program, a 3-year nightly observing program using two 27-meter telescopes at the Owens Valley Radio Observatory (the equivalent of a JVLA baseline). The Starburst program will survey stellar coherent radio bursts in order to characterize the rate and energetics of CMEs on nearby stars, combined with complementary observations to image and characterize the detected CMEs.