Structure and Evolution of Pre-Main Sequence Stars
Abstract
Low-mass pre-main sequence (PMS) stars are strong and variable X-ray emitters, as has been well established by EINSTEIN and ROSAT observatories. It was originally believed that this emission was of thermal nature and primarily originated from coronal activity (magnetically confined loops, in analogy with Solar activity) on contracting young stars. Broadband spectral analysis showed that the emission was not isothermal and that elemental abundances were non-Solar. The resolving power of the Chandra and XMM X-ray gratings spectrometers have provided the first, tantalizing details concerning the physical conditions such as temperatures, densities, and abundances that characterize the X-ray emitting regions of young star. These existing high resolution spectrometers, however, simply do not have the effective area to measure diagnostic lines for a large number of PMS stars over required to answer global questions such as: how does magnetic activity in PMS stars differ from that of main sequence stars, how do they evolve, what determines the population structure and activity in stellar clusters, and how does the activity influence the evolution of protostellar disks. Highly resolved (R>3000) X-ray spectroscopy at orders of magnitude greater efficiency than currently available will provide major advances in answering these questions. This requires the ability to resolve the key diagnostic emission lines with a precision of better than 100 km/s.
Cite
@article{arxiv.0904.3385,
title = {Structure and Evolution of Pre-Main Sequence Stars},
author = {Norbert S. Schulz and Glenn Allen and Mark W. Bautz and Claude C. Canizares and John Davis and Dan Dewey and David P. Huenemoerder and Ralf Heilmann and John Houck and Herman L. Marshall and Mike Nowak and Mark Schattenburg and Marc Audard and Jeremy Drake and Marc Gagne and Joel Kastner and Tim Kallman and Maurice Lautenegger and Julia Lee and Jon Miller and Thierry Montmerle and Koji Mukai and Rachel Osten and Frits Parerels and Andy Pollock and Thomas Preibisch and John Raymond and Fabio Reale and Randall Smith and Paola Testa and David Weintraub},
journal= {arXiv preprint arXiv:0904.3385},
year = {2009}
}
Comments
A White Paper Submitted to the Astro2010 Decadal Survey