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The Gaia-ESO survey: A lithium depletion boundary age for NGC 2232

Published version
Peer-reviewed

Type

Article

Change log

Authors

Binks, AS 
Jeffries, RD 
Jackson, RJ 
Franciosini, E 
Sacco, GG 

Abstract

jats:titleABSTRACT</jats:title> jats:pAstrometry and photometry from Gaia and spectroscopic data from the Gaia-ESO Survey (GES) are used to identify the lithium depletion boundary (LDB) in the young cluster NGC 2232. A specialized spectral line analysis procedure was used to recover the signature of undepleted lithium in very low luminosity cluster members. An age of 38 ± 3 Myr is inferred by comparing the LDB location in absolute colour−magnitude diagrams (CMDs) with the predictions of standard models. This is more than twice the age derived from fitting isochrones to low-mass stars in the CMD with the same models. Much closer agreement between LDB and CMD ages is obtained from models that incorporate magnetically suppressed convection or flux-blocking by dark, magnetic starspots. The best agreement is found at ages of 45−50 Myr for models with high levels of magnetic activity and starspot coverage fractions &gt;50 per cent, although a uniformly high spot coverage does not match the CMD well across the full luminosity range considered.</jats:p>

Description

Keywords

stars: kinematics and dynamics, stars: late-type, stars: pre-main-sequence, solar neighbourhood

Journal Title

Monthly Notices of the Royal Astronomical Society

Conference Name

Journal ISSN

0035-8711
1365-2966

Volume Title

505

Publisher

Oxford University Press (OUP)

Rights

Publisher's own licence
Sponsorship
Leverhulme Trust (RPG-2012-541)
STFC (ST/T003081/1)