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arXiv · 2103.09617

Monoceros OB4: a new association in Gaia DR2

P. S. Teixeira·J. Alves·A. Sicilia-Aguilar·A. Hacar·A. Scholz
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Abstract

We use Gaia DR2 data to survey the classic Monoceros OB1 region and look for the existence of a dispersed young population, co-moving with the cloud complex. An analysis of the distribution of proper motions reveals a 20-30 Myr association of young stars, about 300-400 pc away from the far side of the Mon OB1 complex, along the same general line-of-sight. We characterize the new association, Monoceros OB4, and estimate it contains between 1400 and 2500 stars, assuming a standard IMF, putting it on par in size with NGC\,2264. We find from the internal proper motions that Mon OB4 is unbound and expanding. Our results seem to unveil a larger and more complex Monoceros star formation region, suggesting an elongated arrangement that seems to be at least 300 x 60 pc.

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P. S. Teixeira, J. Alves, A. Sicilia-Aguilar, A. Hacar, A. Scholz. 2021-03-17. Monoceros OB4: a new association in Gaia DR2. https://doi.org/10.1093/mnrasl%2Fslab029

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