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arXiv · 1012.0314

The Decay of Stellar Dynamos and X-ray Activity

Nicholas J. Wright·Jeremy J. Drake·Francesca Civano
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Abstract

Existing stellar X-ray surveys suggest major problems in our understanding of the evolution of stellar magnetic activity in solar and late-type stars, reaching conflicting conclusions over the rate of decay of X-ray activity and the spectral types responsible. We are confronting these discrepancies with a new model of the expected stellar X-ray luminosity distribution, combining a Galactic population synthesis model with current theories for rotational spin- down and the rotation - activity relation for the stellar magnetic dynamo. Here we test our model using new observations of the stellar content of the Chandra COSMOS survey, for which 60 new stellar X-ray sources are identified from the thin disk and Galactic halo populations. Our model is in approximate agreement with the observed X-ray luminosity distribution and the distribution of spectral types responsible. However, slight differences in the form of the X-ray luminosity distribution exist that may hint at problems in our understanding of stellar X-ray emission.

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Nicholas J. Wright, Jeremy J. Drake, Francesca Civano. 2010-12-01. The Decay of Stellar Dynamos and X-ray Activity. https://arxiv.org/abs/1012.0314

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