Science with an ngVLA: Stellar Activity on Red Giant and Supergiant Stars: Mass Loss and the Evolution of the Stellar Dynamo

TL;DR

The ngVLA will significantly advance understanding of stellar activity, mass loss, and dynamo evolution in red giant and supergiant stars through high-resolution, multi-frequency observations of their atmospheres and outflows.

Contribution

This paper highlights the potential of the ngVLA to image stellar surfaces and study atmospheric processes in evolved stars, offering new empirical data to test theoretical models.

Findings

High spatial resolution enables imaging of red supergiant surfaces.

Multi-frequency observations allow thermal continuum tomography.

Synergy with ALMA enhances observational capabilities.

Abstract

In this Chapter we examine the role of the ngVLA to further our understanding of the different manifestations of convective or turbulence-driven stellar activity on red giant and supergiant stars. The combination of high spatial resolution and high sensitivity will enable the ngVLA to significantly improve our understanding of the processes that dissipate energy in the extended atmospheres of cool evolved stars, and drive ubiquitous stellar outflows. The high spatial resolution will enable us to image the surfaces of nearby red supergiants, and to measure the atmospheric extent of red giants. Multi-frequency observations will permit thermal continuum tomography on the largest angular diameter stars, providing key empirical data to test theoretical models. The complementary frequencies and similar spatial resolutions of the ngVLA and ALMA will be a powerful synergy.