Speaker
Description
This project exploits the sensitivity, angular resolution, and high-frequency coverage of AtLAST to investigate key processes in late stellar evolution. We target compact and extended sources linked to post-AGB stars and planetary nebulae. For compact objects, we focus on pre-planetary nebulae with rotating disks, divided into high- and low-momentum subclasses. Using mm-wavelength radio recombination lines and salt emission (NaCl, KCl) as tracers, we will probe ionized cores, jet-launching regions, and dense disks, while C I lines will constrain photodissociation regions and total mass. AtLAST will enable the first statistically significant surveys of these faint tracers, currently limited to few detections. For extended sources, we will map circumstellar envelopes and nebulae to recover mass-loss history and address the “missing mass” problem. Combining CO isotopologues, dense gas tracers (HCN, HNC, HCO$^+$, CN), recombination lines, and C I emission, we will characterize the extent, kinematics, and physico-chemical conditions of faint halos that dominate the mass budget but are filtered out by interferometers. AtLAST’s mapping speed and multi-beam capability will recover diffuse emission on large angular scales with high sensitivity. These observations will constrain jet onset, disk formation, binarity, and chemical evolution across the AGB–pPN–PN transition, providing a comprehensive view of how evolved stars shed and recycle mass into the interstellar medium.