Magnetic activity of Weak-line T Tauri stars, and hunting for planets in terrible (and not-so-terrible) places

Abstract

In recent years Doppler Imaging and Zeeman Doppler Imaging has enabled characterisation of the spots and surface magnetic fields of weak-line T Tauri stars. These objects are nearing the main sequence and so have cleared their inner discs and stopped accreting, but are still contracting and have an evolving internal structure. Examining the large-scale surface brightness and magnetic field maps for a small sample of weak-line T Tauri stars, we find that stars with similar brightness maps can have different magnetic field topologies. The magnetic map results more generally suggest some differences in the large-scale dynamo fields of weak-line T Tauri stars compared with classical T Tauri stars and main sequence stars of a corresponding spectral type.

In addition to studying weak-line T Tauri star magnetic activity, Doppler Imaging allows us to hunt for orbiting close-in giant planets. Early results indicate that the occurrence rate of close-in giant planets is higher among weak-line T Tauri stars than in the main sequence population.

Additionally, I will touch on the work being done at USQ's MINERVA Australis facility following up and measuring masses for planetary system discovered by NASA's TESS mission.