Mass Loss and Stellar Characteristics of Red Supergiants

Red supergiants represent an advanced evolutionary phase of stars with initial masses between roughly 8 and 25 solar masses. Their enormous luminosities and extended atmospheres drive powerful stellar winds that eject material at rates spanning 10⁻⁷ to 10⁻⁴ M⊙ yr⁻¹. This mass loss shapes their transition to core collapse, influences the chemical enrichment of the interstellar medium and regulates feedback processes in galaxies. Observationally, mass-loss rates are inferred from infrared excesses, molecular line profiles and spatially resolved imaging, while effective temperatures, luminosities and surface gravities are derived from spectroscopy and photometry. Theoretical models invoke a combination of pulsation, radiation pressure on dust and large-scale convection to explain episodic and steady winds. Convection cells on scales comparable to the stellar radius can create density inhomogeneities, facilitating dust formation and intermittent ejections. The mass removed during the red supergiant stage determines the final core structure and hence the nature of the ensuing supernova or black-hole remnant. Despite its global importance, the underlying physics of mass loss and atmospheric dynamics in red supergiants remains one of the key uncertainties in massive-star evolution.

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Mass Loss and Stellar Characteristics of Red Supergiants publication trend

The graph below shows the total number of articles in mass loss and stellar characteristics of red supergiants across all publications each year (not limited to Nature Index journals).

Technical terms

Mass-loss rate: The amount of stellar mass expelled per unit time, typically expressed in solar masses per year.

Convection cell: A large-scale flow pattern in a star’s envelope that transports energy by moving hot material outward and cooler material inward.

Supra-Eddington luminosity: A condition in which local radiative flux exceeds the Eddington limit, leading to enhanced mass ejection.

Radiatively driven wind: A stellar outflow propelled by momentum transfer from the star’s radiation field to gas and dust particles.

Spectral energy distribution (SED): The flux of a star measured across a wide range of wavelengths, used to infer temperature, radius and dust content.

References

1. Signatures of convection in the atmospheres of cool evolved stars. Living Reviews in Computational Astrophysics (2024).
2. Evolved massive stars at low-metallicity. Astronomy & Astrophysics (2023).
3. The Time-averaged Mass-loss Rates of Red Supergiants as Revealed by Their Luminosity Functions in M31 and M33. The Astrophysical Journal (2023).