The Gaia-ESO Survey: Revisiting the Li-rich giant problem

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

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 first nine Li-rich giant stars known towards the CoRoT fields. Most of our Li-rich giants have near-solar metallicities and stellar parameters consistent with being before the luminosity bump. This is difficult 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 effort 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 that 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.

Detaljer

Författare
  • A. R. Casey
  • G. Ruchti
  • T. Masseron
  • S. Randich
  • G. Gilmore
  • K. Lind
  • G. M. Kennedy
  • S. E. Koposov
  • A. Hourihane
  • E. Franciosini
  • J. R. Lewis
  • L. Magrini
  • L. Morbidelli
  • G. G. Sacco
  • C. C. Worley
  • R. D. Jeffries
  • A. Vallenari
  • A. Bragaglia
  • E. Flaccomio
  • P. Francois
  • A. J. Korn
  • A. Lanzafame
  • E. Pancino
  • A. Recio-Blanco
  • R. Smiljanic
  • G. Carraro
  • M. T. Costado
  • F. Damiani
  • P. Donati
  • A. Frasca
  • P. Jofré
  • C. Lardo
  • P. de Laverny
  • L. Monaco
  • L. Prisinzano
  • L. Sbordone
  • S. G. Sousa
  • G. Tautvaišiene
  • S. Zaggia
  • T. Zwitter
  • E. Delgado Mena
  • Y. Chorniy
  • S. L. Martell
  • V. Silva Aguirre
  • A. Miglio
  • C. Chiappini
  • J. Montalban
  • T. Morel
  • M. Valentini
Enheter & grupper
Externa organisationer
  • University of Cambridge
  • National Institute for Astrophysics
  • Max Planck Institute for Astronomy
  • Keele University
  • Uppsala universitet, Historiska institutionen
  • University of Porto
  • Vilnius University
  • University of Ljubljana
  • University of New South Wales
  • Aarhus University
  • University of Birmingham
  • Leibniz Institute for Astrophysics Potsdam (AIP)
  • University of Padova
  • University of Liège
  • Paris Diderot University
  • University of Catania
  • Italian Space Agency
  • Université Nice Sophia Antipolis
  • Nicolaus Copernicus Astronomical Center of the Polish Academy of Sciences
  • CSIC Instituto de Astrofísica de Andalucía (IAA)
  • University of Bologna
  • Liverpool John Moores University
  • Andrés Bello National University
  • Millennium Institute of Astrophysics
  • Pontifical Catholic University of Chile
  • European Southern Observatory Santiago
Forskningsområden

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Astronomi, astrofysik och kosmologi

Nyckelord

Originalspråkengelska
Artikelnummerstw1512
Sidor (från-till)3336-3352
Antal sidor17
TidskriftMonthly Notices of the Royal Astronomical Society
Volym461
Utgivningsnummer3
StatusPublished - 2016 sep 21
PublikationskategoriForskning
Peer review utfördJa