Episodic Gaseous Outflows and Mass Loss from Red Supergiants

TL;DR

This paper presents observational evidence that gaseous outflows, driven by magnetic activity and surface phenomena, are a major mass loss mechanism in red supergiants, including VY CMa and Betelgeuse.

Contribution

It provides new measurements and discusses the role of gaseous ejections as a significant, previously underappreciated component of mass loss in red supergiants.

Findings

Gaseous outflows dominate mass loss in luminous RSGs like VY CMa.

Circumstellar condensations contribute significantly to Betelgeuse's mass loss.

Gaseous ejections are linked to magnetic fields and surface activity.

Abstract

The red hypergiant VY CMa and the more typical red supergiant Betelgeuse provide clear observational evidence for discrete, directed gaseous outflows in their optical and infrared imaging, spectra, and light curves. In the very luminous VY CMa, mass loss estimates from the infrared bright knots and clumps, not only dominate its measured overall mass loss, but explain it. In the lower luminosity Betelgeuse, similar mass estimates of its circumstellar condensations show that they contribute significantly to its measured mass loss rate. We present new measurements for both stars and discuss additional evidence for gaseous ejections in other red supergiants. Gaseous outflows are the dominant mass loss mechanism for the most luminous RSGs and an important contributor to the more typical red supergiants like Betelgeuse. We conclude that gaseous outflows, related to magnetic fields and surface activity, comparable to coronal mass ejections, are a major contributor to mass loss from red supergiants and the missing component in discussions of their mass loss mechanism.