Casey, AR, Ruchti, G, Masseron, T, Randich, S, Gilmore, G, Lind, K, Kennedy, GM, Koposov, SE, Hourihane, A, Franciosini, E, Lewis, JR, Magrini, L, Morbidelli, L, Sacco, GG, Worley, CC, Feltzing, S, Jeffries, RD, Vallenari, A, Bensby, T, Bragaglia, A et al (2016) The Gaia-ESO Survey: revisiting the Li-rich giant problem. Monthly Notices of the Royal Astronomical Society, 461 (3). pp. 3336-3352. ISSN 0035-8711
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Abstract
The discovery of lithium-rich giants contradicts expectations from canonical stellar evolution. Here we report on the serendipitous discovery of 20 Li-rich giants observed during the Gaia-ESO Survey, which includes the _rst nine Li-rich giant stars known towards the CoRoT _elds. Most of our Li-rich giants have near-solar metallicities, and stellar parameters consistent with being before the luminosity bump. This is di_cult to reconcile with deep mixing models proposed to explain lithium enrichment, because these models can only operate at later evolutionary stages: at or past the luminosity bump. In an e_ort to shed light on the Li-rich phenomenon, we highlight recent evidence of the tidal destruction of close-in hot Jupiters at the sub-giant phase. We note that when coupled with models of planet accretion, the observed destruction of hot Jupiters actually predicts the existence of Li-rich giant stars, and suggests Li-rich stars should be found early on the giant branch and occur more frequently with increasing metallicity. A comprehensive review of all known Li-rich giant stars reveals that this scenario is consistent with the data. However more evolved or metal-poor stars are less likely to host close-in giant planets, implying that their Li-rich origin requires an alternative explanation, likely related to mixing scenarios rather than external phenomena.
Item Type: | Article |
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Additional Information: | This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved. |
Uncontrolled Keywords: | 0201 Astronomical And Space Sciences |
Subjects: | Q Science > QB Astronomy Q Science > QC Physics |
Divisions: | Astrophysics Research Institute |
Publisher: | Oxford University Press |
Related URLs: | |
Date of acceptance: | 21 June 2016 |
Date of first compliant Open Access: | 22 November 2016 |
Date Deposited: | 22 Nov 2016 11:50 |
Last Modified: | 20 Apr 2022 10:56 |
DOI or ID number: | 10.1093/mnras/stw1512 |
URI: | https://ljmu-9.eprints-hosting.org/id/eprint/4834 |
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