Insights into Young Star Cluster Astrophysics Based on Chandra Observations
Abstract
The pace and pattern of star formation leading to rich young stellar clusters is quite uncertain. For instance, it is unclear whether clusters form monolitically or hierarchically, quickly or slowly; or when and how cluster contraction or expansion occurs. Our recent Massive Young Star-Forming Complex Study in Infrared and X-ray (MYStIX) and Star Formation in Nearby Clouds (SFiNCs) surveys, involving Chandra archive data for over 40 star forming regions and providing rich samples of disky and diskless young stars, were designed to investigate the aforementioned and other astrophysical issues. With over 40,000 identified pre-main sequence stars, Chandra X-ray data give direct estimates of source extinctions, X-ray luminosities, stellar ages, and total intrinsic populations. A few important MYStIX/SFiNCs science results have emerged. First, the discovery of intracluster age gradients in numerous stellar clusters demonstrates late or continuing star formation in support of the astrophysical models involving global hierarchical collapse (GHC) of a cloud. Second, indirect (pre-Gaia) and direct (Gaia-derived) kinematics show prevalent dynamical expansion in clusters that are no longer embedded in their parental clouds, supporting long-standing models of cluster expansion due to gas expulsion. Third, dynamical gas and star contraction in the most prominent nearby site of active star formation, Orion A cloud, again supports GHC cluster formation models.
- Publication:
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American Astronomical Society Meeting Abstracts #235
- Pub Date:
- January 2020
- Bibcode:
- 2020AAS...23522905G