PI: Megan Kiminki, University of Arizona, firstname.lastname@example.org
Address: Dept. of Astronomy / Steward Observatory, 933 N. Cherry Ave., Tucson, AZ 85721, USA
CoI: Nathan Smith, University of Arizona
Title: Using 3D Kinematics to Pinpoint the Birthplaces of Distributed Massive Stars
Abstract: Significant numbers of massive stars are found in distributed populations outside dense clusters. How they came to be there -- whether they were ejected from clusters by various mechanisms or born near their current locations -- is of great importance to our understanding of how massive stars form. Of the two leading massive star formation theories, one (the competitive accretion model) requires that massive stars are born in the center of cluster potentials, while the other (the core accretion model) can operate in less dense environments. To address the question of the origin of distributed massive stars, we propose to use the CHIRON spectrograph on the CTIO- 1.5m to obtain high-resolution spectra of massive stars in the Carina Nebula in order to measure their radial velocities. About half of the Carina Nebula's roughly 70 O-type and massive evolved stars are found outside its central clusters, scattered across more than 30 pc; some are spatially associated with regions of active star formation, suggesting that they formed in place. Combining these radial velocities with proper motions from our ongoing HST/ACS survey will allow us to build a remarkable 3D portrait of these stars' kinematics. With full 3D motions, we can trace individual distributed O-type stars back to their birthplace and determine what fraction of Carina's distributed O-star population was born inside dense clusters.
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