Star-disk interactions in the strongly accreting T Tauri Star S CrA N
Abstract
Aims : We aimed at constraining the accretion-ejection phenomena around the strongly-accreting Northern component of the S CrA young binary system (S CrA N) by deriving its magnetic field topology and its magnetospheric properties, and by detecting ejection signatures, if any. Methods : We led a two-week observing campaign on S CrA N with the ESPaDOnS optical spectropolarimeter at the Canada-France-Hawaii Telescope. We recorded 12 Stokes I and V spectra over 14 nights. We computed the corresponding Least-Square Deconvolution (LSD) profiles of the photospheric lines and performed Zeeman-Doppler Imaging (ZDI). We analysed the kinematics of noticeable emission lines, namely He I and the four first lines of the Balmer series, known to trace the accretion process. Conclusions : The findings from spectropolarimetry are complementary to those provided by optical long-baseline interferometry, allowing us to construct a coherent view of the innermost regions of a young, strongly accreting star. Yet, the strong and complex magnetic field reconstructed for S CrA N is inconsistent with the observed magnetic signatures of the emission lines associated to the post-shock region. We recommend a multi-technique, synchronized campaign of several days to put more constrains on a system that varies on a 1 day timescale.
Keywords
Cite
@article{arxiv.2308.03442,
title = {Star-disk interactions in the strongly accreting T Tauri Star S CrA N},
author = {H. Nowacki and E. Alecian and K. Perraut and B. Zaire and C. P. Folsom and K. Pouilly and J. Bouvier and R. Manick and G. Pantolmos and A. P. Sousa and C. Dougados and G. A. J. Hussain and S. H. P. Alencar and J. B. Le Bouquin},
journal= {arXiv preprint arXiv:2308.03442},
year = {2023}
}