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arXiv · 1807.09262

The low mass population of the Vela OB2 association from Gaia

Joseph J. Armstrong·Nicholas J. Wright·R. D. Jeffries
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Abstract

The first Gaia Data Release presents an opportunity to characterise the low-mass population of OB associations, providing larger statistical samples and better constraints on the formation and evolution of clusters and associations. Using previously known low mass members in a small region of Vela OB2 we have designed selection criteria that combine Gaia and 2MASS photometry, independently of any astrometric information, to identify low-mass pre-main-sequence (PMS) stars over the wider association area. Our method picks out the known clusters of young stars around $\gamma^2$ Velorum and NGC-2547, but also identifies other over-densities that may represent previously unknown clusters. There are clear differences in the spatial distributions of the low-mass and the high-mass OB populations, suggesting either that the structure and dynamics of these populations has evolved separately or that the initial mass function can vary considerably on small scales within a single association.

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Joseph J. Armstrong, Nicholas J. Wright, R. D. Jeffries. 2018-07-24. The low mass population of the Vela OB2 association from Gaia. https://doi.org/10.1093/mnrasl/sly137

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