CFHT UM2025 - Presentation Details
Abstract Details
Title: A Significant Change in the Magnetosphere of the Exoplanet-hosting M-dwarf YZ Cet Discovered with SPIRou
Presenter: Ayan Biswas
Abstract:
The presence of magnetic fields in exoplanets is considered a key factor in habitability. Aurorae, a signature of Star-Planet Interaction (SPI), are observed in all magnetized planets in the solar system and are expected on exoplanets as well. Recently, variable polarized radio emissions were detected from the YZ Cet M-dwarf/exoplanet system, correlated with the planet’s orbit. This emission, likely Auroral Radio Emission from Electron Cyclotron Maser Emission, provides an upper limit on the exoplanet’s magnetic field strength, but this estimate depends on the M dwarf’s magnetic field strength and geometry. To address this, we obtained spectropolarimetric observations from SPIRou on CFHT to characterize the M dwarf’s magnetic field. Combining these data with archival SPIRou observations, we detect significant variations in field strength and geometry over just a few rotation periods. Using Zeeman Doppler Imaging, we map these changes in magnetic topology, offering new insights into the star’s evolving magnetism. Finally, leveraging the obtained magnetic map, we refine estimates of the planetary magnetic field by integrating these results with radio observations of the system.