SIMBAD references

2024MNRAS.534.2014W - Mon. Not. R. Astron. Soc., 534, 2014-2029 (2024/November-1)

Using neural network models to estimate stellar ages from lithium equivalent widths: an EAGLES expansion.

WEAVER G., JEFFRIES R.D. and JACKSON R.J.

Abstract (from CDS):

We present an artificial neural network (ANN) model of photospheric lithium depletion in cool stars ($3000\lt T_{\rm eff}/{\rm K} \lt 6500$), producing estimates and probability distributions of age from $^7$Li 6708 Å equivalent width (LiEW) and effective temperature data inputs. The model is trained on the same sample of 6200 stars from 52 open clusters, observed in the Gaia-ESO spectroscopic survey, and used to calibrate the previously published analytical EAGLES model, with ages 2-6000 Myr and $-0.3 \lt $ [Fe/H] $\lt 0.2$. The additional flexibility of the ANN provides some improvements, including better modelling of the 'lithium dip' at ages $\lt 50$ Myr and $T_{\rm eff}\sim 3500$ K, and of the intrinsic dispersion in LiEW at all ages. Poor age discrimination is still an issue at ages >1 Gyr, confirming that additional modelling flexibility is not sufficient to fully represent the LiEW-age-T$_{\text{eff}}$ relationship, and suggesting the involvement of further astrophysical parameters. Expansion to include such parameters-rotation, accretion, and surface gravity-is discussed, and the use of an ANN means these can be more easily included in future iterations, alongside more flexible functional forms for the LiEW dispersion. Our methods and ANN model are provided in an updated version 2.0 of the EAGLES software.

Abstract Copyright: © 2024 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society.

Journal keyword(s): stars: abundances - stars: evolution - stars: fundamental parameters - stars: pre-main-sequence - Open clusters and associations: general

Status at CDS : Large table(s) will be appraised for possible ingestion in VizieR.

Simbad objects: 20

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