期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 513, 期 4, 页码 5727-5751出版社
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stac1245
关键词
stars: kinematics and dynamics; stars: late-type; stars: pre-main-sequence; (Galaxy:) solar neighbourhood
资金
- STFC
- project PRIN-INAF 2019 'Spectroscopically Tracing the Disk Dispersal Evolution'
- ESO Telescopes at the La Silla Paranal Observatory [188.B-3002]
- UK Science and Technology Facilities Council
- European Union FP7 programme through ERC grant [320360]
- Leverhulme Trust [RPG-2012-541]
- INAF
- Ministero dell' Istruzione, dell' Universit 'a' e della Ricerca (MIUR)
- ESF (European Science Foundation) through the GREAT Research Network Programme
- Spanish MINECO/FEDER at Centro de Astrobiologia (CSIC-INTA) [AYA2017-84089, MDM-2017-0737]
- Unidad de Excelencia Maria de Maeztu
- European Union's Horizon 2020 research and innovation programme through the ESCAPE -The European Science Cluster of Astronomy & Particle Physics ESFRI Research Infrastructures project [824064]
A growing concern has emerged regarding the discrepancies between standard stellar models and observations of pre-main sequence stars in clusters. In this study, researchers tested different models, including those with surface magnetic fields and cool starspots, and found that magnetic models provide better fit for the color-magnitude diagrams and lithium depletion patterns. The study also revealed a correlation between rotation periods and the brightness and lithium depletion of stars.
A growing disquiet has emerged in recent years that standard stellar models are at odds with observations of the colour-magnitude diagrams (CMDs) and lithium depletion patterns of pre-main sequence stars in clusters. In this work we select 1246 high probability K/M-type constituent members of five young open clusters (5-125 Myr) in the Gaia-ESO Survey to test a series of models that use standard input physics and others that incorporate surface magnetic fields or cool starspots. We find that: standard models provide systematically under-luminous isochrones for low-mass stars in the CMD and fail to predict Li-depletion of the right strength at the right colour; magnetic models provide better CMD fits with isochrones that are similar to 1.5-2 times older, and provide better matches to Li depletion patterns. We investigate how rotation periods, most of which are determined here for the first time from 'Transiting Exoplanet Survey Satellite data, correlate with CMD position and Li. Among the K-stars in the older clusters we find the brightest and least Li-depleted are the fastest rotators, demonstrating the classic 'Li-rotation connection' for the first time at similar to 35 Myr in NGC 2547, and finding some evidence that it exists in the early M-stars of NGC 2264 at < 10 Myr. However, the wide dispersion in Li depletion observed in fully convective M-dwarfs in the gamma Vel cluster at similar to 20 Myr appears not to be correlated with rotation and is challenging to explain without a very large (> 10 Myr) age spread.
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