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arXiv · 0905.1690

X-ray Photoevaporation-starved T Tauri Accretion

Jeremy J. Drake·Barbara Ercolano·Ettore Flaccomio·Giusi Micela
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Abstract

X-ray luminosities of accreting T Tauri stars are observed to be systematically lower than those of non-accretors. There is as yet no widely accepted physical explanation for this effect, though it has been suggested that accretion somehow suppresses, disrupts or obscures coronal X-ray activity. Here, we suggest that the opposite might be the case: coronal X-rays modulate the accretion flow. We re-examine the X-ray luminosities of T Tauri stars in the Orion Nebula Cluster and find that not only are accreting stars systematically fainter, but that there is a correlation between mass accretion rate and stellar X-ray luminosity. We use the X-ray heated accretion disk models of Ercolano et al. to show that protoplanetary disk photoevaporative mass loss rates are strongly dependent on stellar X-ray luminosity and sufficiently high to be competitive with accretion rates. X-ray disk heating appears to offer a viable mechanism for modulating the gas accretion flow and could be at least partially responsible for the observed correlation between accretion rates and X-ray luminosities of T Tauri stars.

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Jeremy J. Drake, Barbara Ercolano, Ettore Flaccomio, Giusi Micela. 2009-05-11. X-ray Photoevaporation-starved T Tauri Accretion. https://doi.org/10.1088/0004-637x%2F699%2F1%2Fl35

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