Why are accreting T Tauri stars less luminous in X-rays than non-accretors?

TL;DR

This study investigates why accreting T Tauri stars emit less X-ray radiation than non-accretors by modeling magnetic fields and accretion flows, revealing absorption by dense gas in accretion columns as a key factor.

Contribution

First combined radiative transfer with magnetic field models from Zeeman-Doppler imaging to study X-ray absorption in accreting T Tauri stars.

Findings

X-ray emission is strongly absorbed by dense accretion columns.

Magnetic field topology influences X-ray propagation.

Accretion-related absorption explains lower X-ray luminosity.

Abstract

Accreting T Tauri stars are observed to be less luminous in X-rays than non-accretors, an effect that has been detected in various star forming regions. To explain this we have combined, for the first time, a radiative transfer code with an accretion model that considers magnetic fields extrapolated from surface magnetograms obtained from Zeeman-Doppler imaging. Such fields consist of compact magnetic regions close to the stellar surface, with extended field lines interacting with the disk. We study the propagation of coronal X-rays through the magnetosphere and demonstrate that they are strongly absorbed by the dense gas in accretion columns.