Evolution, nucleosynthesis and yields of AGB stars at different metallicities (III): intermediate mass models, revised low mass models and the ph-FRUITY interface

TL;DR

This paper introduces new models for intermediate mass AGB stars across various metallicities, detailing their evolution, nucleosynthesis, and the updated FRUITY database interface, highlighting differences from low mass models and implications for stellar observations.

Contribution

It provides a comprehensive set of intermediate mass AGB star models at different metallicities, integrating them into the FRUITY database with an upgraded web interface and detailed physical and chemical evolution analysis.

Findings

Models show modest surface enhancements due to less efficient dredge-up.

Heavy element nucleosynthesis varies with initial mass and metallicity.

The models' final core masses align with white dwarf observations.

Abstract

We present a new set of models for intermediate mass AGB stars (4.0, 5.0 and, 6.0 Msun) at different metallicities (-2.15<=Fe/H]<=+0.15). This integrates the existing set of models for low mass AGB stars (1.3<=M/M<=3.0) already included in the FRUITY database. We describe the physical and chemical evolution of the computed models from the Main Sequence up to the end of the AGB phase. Due to less efficient third dredge up episodes, models with large core masses show modest surface enhancements. The latter is due to the fact that the interpulse phases are short and, then, Thermal Pulses are weak. Moreover, the high temperature at the base of the convective envelope prevents it to deeply penetrate the radiative underlying layers. Depending on the initial stellar mass, the heavy elements nucleosynthesis is dominated by different neutron sources. In particular, the s-process distributions of the more massive models are dominated by the \nean~reaction, which is efficiently activated during Thermal Pulses. At low metallicities, our models undergo hot bottom burning and hot third dredge up. We compare our theoretical final core masses to available white dwarf observations. Moreover, we quantify the weight that intermediate mass models have on the carbon stars luminosity function. Finally, we present the upgrade of the FRUITY web interface, now also including the physical quantities of the TP-AGB phase of all the models included in the database (ph-FRUITY).