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Paper: Extreme Coronal Mass Ejections in Young Low-Mass Stars
Volume: 448, 16th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun
Page: 43
Authors: Aarnio, A. N.; Stassun, K. G.; Matt, S. P.; Hughes, W. J.; McGregor, S. L.
Abstract: Two long-standing questions in the study of young, low-mass stars are: (1) What are the mechanisms that govern the observed order-of-magnitude decrease of stellar angular momentum during pre-main-sequence evolution, and (2) What are the physical drivers of X-ray production in these stars at up to 104 times the solar value? Application of solar flare models to the most powerful X-ray flares observed among T Tauri stars in Orion suggests that the flares are produced by magnetic loop structures with lengths of up to tens of stellar radii. We present new results demonstrating that, for the majority of these stars, the extremely large flaring structures are not anchored to or stabilized by circumstellar disks. Given the energy and size scales involved, mass losses (e.g., via stellar coronal mass ejections—CMEs—associated with these flares) at such large effective lever arms could shed substantial angular momentum. To begin estimating the attendant angular momentum losses of such extreme CMEs in young stars, we have assembled from the solar literature a database of ∼10,000 X-ray flares and CMEs, from which we determine for the first time the empirical relationship between solar X-ray flare energy and CME ejected mass. Finally, we demonstrate how our flare flux/CME mass relationship can be used to estimate stellar angular momentum loss via extreme CMEs in young stars.
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