The GRAVITY young stellar object survey XIV : Investigating the magnetospheric accretion-ejection processes in S CrA N

TL;DR

This study uses near-infrared interferometry to explore the innermost accretion and ejection processes around the young star S CrA N, revealing the role of magnetospheric accretion and disk winds in its emission features.

Contribution

It provides new insights into the physical mechanisms of magnetospheric accretion and ejection in the inner regions of a young stellar object using interferometric observations.

Findings

Dusty ring explains continuum emission size

Magnetospheric accretion heats dust beyond sublimation

Brγ line originates from accretion-ejection processes

Abstract

The dust- and gas-rich protoplanetary disks around young stellar systems play a key role in star and planet formation. While considerable progress has recently been made in probing these disks on large scales of a few tens of astronomical units (au), the central au needs to be more investigated. We aim at unveiling the physical processes at play in the innermost regions of the strongly accreting T Tauri Star S CrA N by means of near-infrared interferometric observations. The K-band continuum emission is well reproduced with an azimuthally-modulated dusty ring. As the star alone cannot explain the size of this sublimation front, we propose that magnetospheric accretion is an important dust-heating mechanism leading to this continuum emission. The differential analysis of the Hydrogen Br$\gamma$ line is in agreement with radiative transfer models combining magnetospheric accretion and disk winds. Our observations support an origin of the Br$\gamma$ line from a combination of (variable) accretion-ejection processes in the inner disk region.