The magnetic propeller accretion regime of LkCa 15
Abstract
We present a spectropolarimetric study of the classical T Tauri star (cTTS) LkCa 15 investigating the large-scale magnetic topology of the central star and the way the field connects to the inner regions of the accretion disc. We find that the star hosts a strong poloidal field with a mainly axisymmetric dipole component of 1.35 kG, whereas the mass accretion rate at the surface of the star is \hbox{{\rm M}_{\odot}^{-1}}. It implies that the magnetic field of LkCa 15 is able to evacuate the central regions of the disc up to a distance of 0.07 au at which the Keplerian orbital period equals the stellar rotation period. Our results suggest that LkCa 15, like the lower-mass cTTS AA Tau, interacts with its disc in a propeller mode, a regime supposedly very efficient at slowing down the rotation of cTTSs hosting strong dipolar fields.
Keywords
Cite
@article{arxiv.1811.04810,
title = {The magnetic propeller accretion regime of LkCa 15},
author = {J-F Donati and J Bouvier and SH Alencar and C Hill and A Carmona and CP Folsom and F Menard and SG Gregory and GA Hussain and K Grankin and C Moutou and L Malo and M Takami and GJ Herczeg and the MaTYSSE collaboration},
journal= {arXiv preprint arXiv:1811.04810},
year = {2018}
}
Comments
MNRAS letter, in press (3 figures, 1 table)