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

TY - JOUR

T1 - Why are accreting T Tauri stars observed to be less luminous in X-rays than non-accretors?

AU - Gregory, S. G.

AU - Wood, K.

AU - Jardine, M.

PY - 2007/7/1

Y1 - 2007/7/1

N2 - 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 disc. 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. The reduction in the observed X-ray emission depends on the field geometry, which may explain why accreting T Tauri stars show a larger scatter in their observed X-ray luminosity compared with non-accreting stars.

AB - 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 disc. 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. The reduction in the observed X-ray emission depends on the field geometry, which may explain why accreting T Tauri stars show a larger scatter in their observed X-ray luminosity compared with non-accreting stars.

KW - Stars: activity

KW - stars: coronae

KW - stars: magnetic fields

KW - Stars: pre-main-sequence

KW - X-rays: stars

UR - https://arxiv.org/abs/0704.2958

UR - https://ui.adsabs.harvard.edu/abs/2007MNRAS.379L..35G/abstract

U2 - 10.1111/j.1745-3933.2007.00328.x

DO - 10.1111/j.1745-3933.2007.00328.x

M3 - Article

SN - 1745-3925

VL - 379

SP - L35-L39

JO - Monthly Notices of the Royal Astronomical Society: Letters

JF - Monthly Notices of the Royal Astronomical Society: Letters

IS - 1

ER -