Karnath, N, Prchlik, JJ, Gutermuth, RA, Allen, TS, Megeath, ST, Pipher, JL, Wolk, S and Jeffries, RD (2019) The Dynamics, Structure, and Fate of a Young Cluster during Gas Dispersal: Hectoschelle, Chandra, Spitzer, and Gaia Observations of Cep OB3b. Astrophysical Journal, 871 (1). ISSN 0004-637X

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We present a study of the kinematics and structure of the Cep OB3b cluster based on new spectra obtained with the Hectoschelle spectrograph on the MMT and data from Spitzer, Chandra, and Gaia. At a distance of 819 +/- 16 pc, Cep OB3b is one of the closest examples of a young (similar to 3-5 Myr), large (similar to 3000 total members) cluster at the late stages of gas dispersal. The cluster is broken into two subclusters surrounded by a lower density halo. We fit the empirical density law of King to each subcluster to constrain their sizes and structure. The richer eastern subcluster has circular symmetry, a modest central density, and lacks molecular gas toward its core, suggesting it has undergone expansion due to gas dispersal. In contrast, the western subcluster deviates from circular symmetry, has a smaller core size, and contains significant molecular gas near its core, suggesting that it is in an earlier phase of gas dispersal. We present posterior probability distributions for the velocity dispersions from the Hectoschelle spectra. The east will continue to expand and likely form a bound cluster with similar to 35% of stars remaining. The west is undergoing slower gas dispersal and will potentially form a bound cluster with similar to 75% of stars remaining. If the halo dissipates, this will leave two independent clusters with similar to 300 members; proper motions suggest that the two subcluster are not bound to each other.

Item Type: Article
Additional Information: © 2019 The American Astronomical Society. This is the final published version of the article (version of record). It first appeared online via IOP at https://doi.org/10.3847/1538-4357/aaf4c1 - please refer to any applicable terms of use of the publisher.
Uncontrolled Keywords: open clusters and associations, CEP OB3b, stars, formation, kinematics and dynamics, pre-main sequence, techniques, radial velocities
Subjects: Q Science > QB Astronomy > QB460 Astrophysics
Divisions: Faculty of Natural Sciences > School of Chemical and Physical Sciences
Depositing User: Symplectic
Date Deposited: 07 Feb 2019 10:54
Last Modified: 11 Feb 2019 12:31
URI: https://eprints.keele.ac.uk/id/eprint/5781

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