CAREER: Monitoring for Signs of Magnetospheres Around Extrasolar Planets

California Institute Of Technology, Pasadena CA

Investigators

Abstract

Stars eject material into the space surrounding them. Theses ejections create shock waves that move outward from the stars, and show up as bursts of signal at low radio frequencies. When these shock waves hit planets around these other stars that have magnetospheres (like the Earth), the planets should also increase in radio signal strength. If we detect this radio emission from a planet, we learn that it has a magnetosphere that can shield the planet from outside radiation and protect any biology that could be present. The investigator will use the Owens Valley Long Wavelength Array radio telescope to search for these signals from 2500 planetary systems continuously over 5 years. This project serves the national interest as it helps our search for planets around other stars that could have life, and our understanding of the properties of these planets. The investigator will work with high school students from the Pasadena Unified School District to make a live continuous update of the low frequency radio sky seen by the radio telescope for the front page of spaceweather.com, reaching a broad, public audience. Stellar coronal mass ejections produce bright radio bursts at low frequencies (typically <100 MHz), which are generated as the resulting shockwave propagates through the corona and interplanetary medium. Similarly, exoplanets with magnetospheres that encounter these shockwaves can also increase in radio luminosity by orders of magnitude. Planetary magnetospheres serve as shields for potential biospheres from harmful high-energy particles from the host star and beyond. The detection of this radio emission at an exoplanet would be very significant, as it allows the direct measurement of the magnetic field strength of the planet, indicating whether the atmosphere of the planet can survive the intense magnetic activity of its host star. The investigator will use the Owens Valley Long Wavelength Array (OVRO-LWA) to monitor every stellar system out to 25 parsecs (>2500 systems) continuously for a 5-year period, in an effort to detect such events. As well as providing the first direct confirmation of the presence, strength and extent of an exoplanetary magnetosphere, a detection allows inference of the nature of the exoplanet?s interior and provides the capability to characterize physical properties such as planetary rotation rate and inclination of rotational and orbital axes. The investigator will work with high school students from the Pasadena Unified School District to develop a publicly accessible, web-based, live update of the low frequency radio sky, as seen by the OVRO-LWA. This live update will be continuously shown on the front page of spaceweather.com, placing these students at the interface between scientific data and a broad, public audience.