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Dalessandro, E, Cadelano, M, Vesperini, E, Salaris, M, Ferraro, FR, Lanzoni, B, Raso, S, Hong, J, Webb, JJ and Zocchi, A (2018) The Peculiar Radial Distribution of Multiple Populations in the Massive Globular Cluster M80. Astrophysical Journal, 859 (1). ISSN 0004-637X
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The Peculiar Radial Distribution of Multiple Populations in the Massive Globular Cluster M80.pdf - Accepted Version Download (3MB) | Preview |
Abstract
We present a detailed analysis of the radial distribution of light-element multiple populations (LE-MPs) in the massive and dense globular cluster M80, based on a combination of UV and optical Hubble Space Telescope data. Surprisingly, we find that first-generation (FG) stars (FG) are significantly more centrally concentrated than extreme second-generation (SG) stars out to ∼2.5rhfrom the cluster center. To understand the origin of such peculiar behavior, we used a set of N-body simulations following the long-term dynamical evolution of LE-MPs. We find that, given the advanced dynamical state of the cluster, the observed difference does not depend on the primordial relative distributions of FG and SG stars. On the contrary, a difference of ∼0.05-0.10 Mobetween the average masses of the two subpopulations is needed to account for the observed radial distributions. We argue that such a mass difference might be the result of the higher He abundance of SG stars (of the order of ΔY ∼0.05-0.06) with respect to FG stars. Interestingly, we find that a similar He variation is necessary to reproduce the horizontal branch morphology of M80. These results demonstrate that differences in mass among LE-MPs, due to different He content, should be properly taken into account for a correct interpretation of their radial distribution, at least in dynamically evolved systems. © 2018. The American Astronomical Society. All rights reserved..
| Item Type: | Article |
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| Uncontrolled Keywords: | 0201 Astronomical And Space Sciences, 0305 Organic Chemistry, 0306 Physical Chemistry (Incl. Structural) |
| Subjects: | Q Science > QB Astronomy Q Science > QC Physics |
| Divisions: | Astrophysics Research Institute |
| Publisher: | American Astronomical Society; IOP Publishing |
| Date Deposited: | 25 Jun 2018 09:38 |
| Last Modified: | 04 Sep 2021 10:22 |
| DOI or ID number: | 10.3847/1538-4357/aabb56 |
| URI: | https://researchonline.ljmu.ac.uk/id/eprint/8885 |
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