The Influence of Radiative Core Growth on Coronal X-Ray Emission from Pre
View metadata, citation and similar papers at core.ac.uk brought to you by CORE MNRAS Advance Access published February 2, 2016 provided by St Andrews Research Repository MNRAS 000, 1–22 (2015) Preprint 30 January 2016 Compiled using MNRAS LATEX style file v3.0 The influence of radiative core growth on coronal X-ray emission from pre-main sequence stars Scott G. Gregory,1? Fred C. Adams2;3 and Claire L. Davies4;1 1SUPA, School of Physics & Astronomy, University of St Andrews, St Andrews, KY16 9SS, U.K. 2Physics Department, University of Michigan, Ann Arbor, MI 48109, U.S.A. 3Astronomy Department, University of Michigan, Ann Arbor, MI 48109, U.S.A. 4School of Physics, University of Exeter, Exeter, EX4 4QL, U.K. Downloaded from Accepted XXX. Received YYY; in original form ZZZ ABSTRACT Pre-main sequence (PMS) stars of mass & 0:35 M transition from hosting fully convective interiors to configurations with a radiative core and outer convective envelope during their http://mnras.oxfordjournals.org/ gravitational contraction. This stellar structure change influences the external magnetic field topology and, as we demonstrate herein, affects the coronal X-ray emission as a stellar analog of the solar tachocline develops. We have combined archival X-ray, spectroscopic, and photo- metric data for ∼1000 PMS stars from five of the best studied star forming regions; the ONC, NGC 2264, IC 348, NGC 2362, and NGC 6530. Using a modern, PMS calibrated, spectral type-to-effective temperature and intrinsic colour scale, we deredden the photometry using colours appropriate for each spectral type, and determine the stellar mass, age, and internal structure consistently for the entire sample.
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