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Linking globular cluster structural parameters and their evolution: multiple stellar populations

Mastrobuono-Battisti, Alessandra and Perets, Hagai B. (2021) Linking globular cluster structural parameters and their evolution: multiple stellar populations. Monthly Notices of the Royal Astronomical Society, 505 (2). pp. 2548-2560. ISSN 0035-8711. doi:10.1093/mnras/stab1407. https://resolver.caltech.edu/CaltechAUTHORS:20210819-234526412

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Abstract

Globular clusters (GCs) are known to host multiple stellar populations showing chemical anomalies in the content of light elements. The origin of such anomalies observed in Galactic GCs is still debated. Here we analyse data compiled from the Hubble Space Telescope, ground-based surveys, and Gaia Data Release 2 (DR2) and explore relationships between the structural properties of GCs and the fraction of second population (2P) stars. Given the correlations we find, we conclude that the main factor driving the formation/evolution of 2P stars is the cluster mass. The existing strong correlations between the 2P fraction and the rotational velocity and concentration parameter could derive from their correlation with the cluster mass. Furthermore, we observe that increasing cluster escape velocity corresponds to higher 2P fractions. Each of the correlations found is bimodal, with a different behaviour detected for low- and high-mass (or escape velocity) clusters. These correlations could be consistent with an initial formation of more centrally concentrated 2P stars in deeper cluster potentials, followed by a long-term tidal stripping of stars from clusters outskirts. The latter are dominated by the more extended distributed first population (1P) stars, and therefore stronger tidal stripping would preferentially deplete the 1P population, raising the cluster 2P fraction. This also suggests a tighter distribution of initial 2P fractions than observed today. In addition, higher escape velocities allow better retention of low-velocity material ejected from 1P stars, providing an alternative/additional origin for the observed differences and the distributions of 2P fractions amongst GCs.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1093/mnras/stab1407DOIArticle
https://arxiv.org/abs/2011.12292arXivDiscussion Paper
ORCID:
AuthorORCID
Mastrobuono-Battisti, Alessandra0000-0002-2386-9142
Perets, Hagai B.0000-0002-5004-199X
Additional Information:© 2021 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model). Accepted 2021 May 12. Received 2021 May 12; in original form 2020 November 20. Published: 19 May 2021. The authors thank the referee for the helpful and careful comments that improved this work and A. F. Marino and A. Milone for the useful discussion and comments. AM-B is supported by the Swedish Research Council (grant 2017-04217). Data Availability: The data underlying this paper are available in the paper and in the cited literature.
Funders:
Funding AgencyGrant Number
Swedish Research Council2017-04217
Subject Keywords:globular clusters: general – Galaxy: kinematics and dynamics – Galaxy: stellar content
Issue or Number:2
DOI:10.1093/mnras/stab1407
Record Number:CaltechAUTHORS:20210819-234526412
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20210819-234526412
Official Citation:Alessandra Mastrobuono-Battisti, Hagai B Perets, Linking globular cluster structural parameters and their evolution: multiple stellar populations, Monthly Notices of the Royal Astronomical Society, Volume 505, Issue 2, August 2021, Pages 2548–2560, https://doi.org/10.1093/mnras/stab1407
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:110316
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:20 Aug 2021 17:01
Last Modified:20 Aug 2021 17:01

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