The Red and Yellow Hypergiants

Abstract

The red and yellow hypergiants are a rare and important phase in the evolution of the most massive stars that can reach the cool part of the HR Diagram. The hypergiant phase is commonly characterized by high, often episodic mass-loss rates and significant changes in spectral type, probably due to the formation of a pseudo photopsphere during a high mass-loss episode. Many of the yellow hypergiants are the immediate successors to the most luminous red supergiants, and often show evidence in their dusty, circumstellar envelopes from past red supergiant activity. In this paper we review the yellow and red hypergiants with an emphasis on how they differ from more normal red supergiants.

Invited review for the Galaxies Special Issue on "Red Supergiants -- Crucial Signposts for the Fate of Massive Stars." 15 pages, 6 figures

References in corpus (29)

• The death of massive stars - I. Observational constraints on the progenitors of type II-P supernovae
• The 3D Morphology of VY Canis Majoris. I The Kinematics of the Ejecta
• A Diversity of Wave-driven Pre-supernova Outbursts
• Fundamental properties and atmospheric structure of the red supergiant VY CMa based on VLTI/AMBER spectro-interferometry
• Multiple ring nebulae around blue supergiants
• The evolution of Red Supergiants to supernova in the LMC cluster NGC 2100
• The close circumstellar environment of Betelgeuse - II. Diffraction-limited spectro-imaging from 7.76 to 19.50 microns with VLT/VISIR
• Evolved Massive Stars at Low-metallicity V. Mass-Loss Rate of Red Supergiant Stars in the Small Magellanic Cloud
• ALMA Observations of Anisotropic Dust Mass-loss in the Inner Circumstellar Environment of the Red Supergiant VY Canis Majoris
• Discrepancies in the ages of young star clusters; evidence for mergers?
• Episodic Gaseous Outflows and Mass Loss from Red Supergiants
• Exploring the Mass Loss Histories of the Red Supergiants
• Integral-Field Spectroscopy of the Post Red Supergiant IRC +10420: evidence for an axi-symmetric wind
• The 3D Morphology of VY Canis Majoris II: Polarimetry and the Line-of-Sight Distribution of the Ejecta
• Imaging the Cool Hypergiant NML Cygni's Dusty Circumstellar Envelope with Adaptive Optics
• Short Term Variability of Evolved Massive Stars with TESS II: A New Class of Cool, Pulsating Supergiants
• On massive dust clumps in the envelope of the red supergiant VY Canis Majoris
• Optical/near-infrared observations of the Fried Egg Nebula: Multiple shell ejections on a 100 yr timescale from a massive yellow hypergiant
• Three-dimensional imaging of convective cells in the photosphere of Betelgeuse
• Yellow Supergiants and Post-Red Supergiant Evolution in the Large Magellanic Cloud
• Red Supergiants, Yellow Hypergiants, and Post-RSG Evolution
• Long Term Evolution of Surface Features on the Red Supergiant AZ Cyg
• Constraints on the Surface Magnetic Fields and Age of a Cool Hypergiant: XMM-Newton X-ray Observations of VY CMa
• ALMA Compact Array observations of the Fried Egg nebula: Evidence for large-scale asymmetric mass-loss from the yellow hypergiant IRAS 17163-3907
• Images of Betelgeuse with VLTI/MATISSE across the Great Dimming
• The Great Dimming of Betelgeuse: the photosphere as revealed by tomography over the past 15 years
• Imaging the innermost circumstellar environment of the red supergiant WOH G64 in the Large Magellanic Cloud
• Tracing a decade of activity towards a yellow hypergiant. The spectral and spatial morphology of IRC+10420 at au scales
• Dense molecular clumps in the envelope of the yellow hypergiant IRC+10420