CFHT UM2025 - Presentation Details
Abstract Details
Title: A multi-kiloGauss field driving the accretion in EX Lupi: The EXors bursts mystery finally solved ?
Presenter: Kim Pouilly
Abstract:
In this work we will present the first ever magnetic field analysis of EX Lupi, the prototypical EXor-type star. These objects are classical T Tauri stars, supposedly accreting from the disk through magnetospheric accretion. The strong magnetic field of the star truncates the disc at a few stellar radii and force the disc’s material to leave its plan to freefall onto the star following the magnetic field lines. The particularity of EXors is that they show bursts and outbursts events ascribed to episodic accretion. These events produce luminosity increase of 1-5 magnitude in the optical frame lasting for a few months to a few years and can occur repeatedly. The aim of this study is to investigate the connection between accretion, eruptive events, and the magnetic field of EXors. To do so, we analyse a unique dataset of ESPaDOnS and SPIRou high-resolution spectropolarimetric spectra, to study the accretion process along the stellar rotation cycle, together with its large- and small-scale magnetic field configuration. This work is the first joint analysis of the magnetic field and accretion process for an EXor-type star. The impact of the magnetic field in the episodic accretion of EX Lupi will be discussed in this contribution.