Evolution of asymptotic giant branch stars II. Optical to far-infrared isochrones with improved TP-AGB models

TL;DR

This paper introduces a comprehensive set of improved theoretical isochrones for asymptotic giant branch stars, covering optical to far-infrared wavelengths, with detailed treatment of the TP-AGB phase and dust effects, useful for stellar population studies.

Contribution

It provides a new, detailed set of TP-AGB stellar isochrones with enhanced modeling of dust effects, available across multiple photometric systems and accessible via web tools.

Findings

Enhanced TP-AGB modeling improves isochrone accuracy.

Isochrones cover 20+ photometric systems, including infrared.

Dust correction enhances optical to far-IR predictions.

Abstract

We present a large set of theoretical isochrones, whose distinctive features mostly reside on the greatly improved treatment of the thermally pulsing asymptotic giant branch (TP-AGB) phase. Essentially, we have coupled the TP-AGB tracks described in Paper I, at their stages of pre-flash quiescent H-shell burning, with the evolutionary tracks for the previous evolutionary phases from Girardi et al. (2000). Theoretical isochrones for any intermediate value of age and metallicity are then derived by interpolation in the grids. We take care that the isochrones keep, to a good level of detail, the several peculiarities present in these TP-AGB tracks. Theoretical isochrones are then converted to about 20 different photometric systems -- including traditional ground-based systems, and those of recent major wide-field surveys such as SDSS, OGLE, DENIS, 2MASS, UKIDSS, etc., -- by means of synthetic photometry applied to an updated library of stellar spectra, suitably extended to include C-type stars. Finally, we correct the predicted photometry by the effect of circumstellar dust during the mass-losing stages of the AGB evolution, which allows us to improve the results for the optical-to-infrared systems, and to simulate mid- and far-IR systems such as those of Spitzer and AKARI. Access to the data is provided both via a web repository of static tables (http://stev.oapd.inaf.it/dustyAGB07 and CDS), and via an interactive web interface (http://stev.oapd.inaf.it/cmd) that provides tables for any intermediate value of age and metallicity, for several photometric systems, and for different choices of dust properties.