# Astro2020: Unlocking the Secrets of Late-Stage Stellar Evolution and Mass Loss through Radio Wavelength Imaging

## TL;DR

This paper discusses how radio wavelength imaging can reveal critical details about the mass loss processes in late-stage stellar evolution, which are essential for understanding stellar and galactic evolution.

## Contribution

It highlights the potential of upcoming radio observations to resolve key uncertainties in the physics of stellar mass loss during late evolutionary phases.

## Key findings

- Radio imaging can resolve stellar atmospheres and ejecta.
- Mass loss mechanisms and geometries can be better understood.
- Implications for galaxy evolution and cosmology.

## Abstract

During the late phases of evolution, low-to-intermediate mass stars like our Sun undergo periods of extensive mass loss, returning up to 80% of their initial mass to the interstellar medium. This mass loss profoundly affects the stellar evolutionary history, and the resulting circumstellar ejecta are a primary source of dust and heavy element enrichment in the Galaxy. However, many details concerning the physics of late-stage stellar mass loss remain poorly understood, including the wind launching mechanism(s), the mass loss geometry and timescales, and the mass loss histories of stars of various initial masses. These uncertainties have implications not only for stellar astrophysics, but for fields ranging from star formation to extragalactic astronomy and cosmology. Observations at centimeter, millimeter, and submillimeter wavelengths that resolve the radio surfaces and extended atmospheres of evolved stars in space, time, and frequency are poised to provide groundbreaking new insights into these questions in the coming decade.