Red Supergiants in the Milky Way and Nearby Galaxies

Abstract

Identifications of red supergiants (RSGs) in the Milky Way and nearby galaxies have experienced an exponential increase in recent years, driven by advancements in selection techniques, the continued expansion of archival datasets, and a steady increase in spectroscopic data. This review describes the advances in methodologies and selection criteria for identifying RSGs and presents the current census of these stars in our own Galaxy and nearby galaxies. It also describes the insights gained from resolving nearby RSGs and their complex circumstellar material in the Milky Way and from the growing samples of RSGs being discovered in the Local Group and beyond. These advances impact the Humphreys--Davidson limit in the cool part of the Hertzsprung--Russell diagram. Furthermore, they provide insight into extreme RSGs and the role of photometric variability and, in particular, of the newly discovered phenomenon of dimming events. Recent observations have enabled the determination of the binarity fraction among RSGs, offering new constraints to stellar evolution. Looking ahead, the synergy between large-scale surveys, high-resolution observations, and emerging machine-learning tools promises to further transform our understanding of the final evolutionary stages of massive stars in the coming decade.

19 pages, 5 figures, Invited review for the Galaxies Special Issue on "Red Supergiants -- Crucial Signposts for the Fate of Massive Stars."

References in corpus (81)

• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• Binary interaction dominates the evolution of massive stars
• A distance to the Large Magellanic Cloud that is precise to one per cent
• A Survey of Local Group Galaxies Currently Forming Stars. I. UBVRI Photometry of Stars in M31 and M33
• Spitzer SAGE Infrared Photometry of Massive Stars in the Large Magellanic Cloud
• The Effective Temperatures and Physical Properties of Magellanic Cloud Red Supergiants: The Effects of Metallicity
• Variability in red supergiant stars: pulsations, long secondary periods and convection noise
• A new mass-loss rate prescription for red supergiants
• A Survey of Local Group Galaxies Currently Forming Stars: III. A Search for Luminous Blue Variables and Other H-alpha Emission-Lined Stars
• Spitzer SAGE-SMC Infrared Photometry of Massive Stars in the Small Magellanic Cloud
• Discovery of an Extraordinarily Massive Cluster of Red Supergiants
• POSYDON: A General-Purpose Population Synthesis Code with Detailed Binary-Evolution Simulations
• The impact of mass-loss on the evolution and pre-supernova properties of red supergiants
• The dust condensation sequence in red super-giant stars
• The PHANGS-JWST Treasury Survey: Star Formation, Feedback, and Dust Physics at High Angular resolution in Nearby GalaxieS
• A dusty veil shading Betelgeuse during its Great Dimming
• A third red supergiant rich cluster in the Scutum-Crux Arm
• The Araucaria Project: the Local Group Galaxy WLM--Distance and metallicity from quantitative spectroscopy of blue Supergiants
• Late-Type Red Supergiants: Too Cool for the Magellanic Clouds?
• Standing on the shoulders of giants: New mass and distance estimates for Betelgeuse through combined evolutionary, asteroseismic, and hydrodynamical simulations with MESA
• Red Supergiant Stars as Cosmic Abundance Probes: KMOS Observations in NGC 6822
• The Period-Luminosity Relation of Red Supergiant Stars in the Small Magellanic Cloud
• Discovery of a Thorne-Zytkow object candidate in the Small Magellanic Cloud
• A search for counterparts to massive X-ray binaries using photometric catalogues
• Red Supergiant Stars as Cosmic Abundance Probes. III. NLTE effects in J-band Magnesium lines
• Red Supergiants as Cosmic Abundance Probes: The Magellanic Clouds
• Spatially resolved dusty torus toward the red supergiant WOH G64 in the Large Magellanic Cloud
• A new survey of cool supergiants in the Magellanic Clouds
• Red Supergiants as Cosmic Abundance Probes: The Sculptor Galaxy NGC 300
• Red Supergiant Stars in the Large Magellanic Cloud: I. The Period-Luminosity Relation
• Evolved Massive Stars at Low-metallicity V. Mass-Loss Rate of Red Supergiant Stars in the Small Magellanic Cloud
• An Updated 2017 Astrometric Solution for Betelgeuse
• Red Supergiants as Cosmic Abundance Probes: massive star clusters in M83, and the mass-metallicity relation of nearby galaxies
• The VLT-FLAMES Tarantula Survey. XXX. Red stragglers in the clusters Hodge 301 and SL 639
• Red supergiants around the obscured open cluster Stephenson 2
• ALMA sub-mm maser and dust distribution of VY Canis Majoris
• The period-luminosity relation of red supergiants with Gaia DR2
• Discrepancies in the ages of young star clusters; evidence for mergers?
• The Red Supergiant Content of M31 and M33
• The Luminosity Function of Red Supergiants in M31
• The Time-Averaged Mass-Loss Rates of Red Supergiants As Revealed by their Luminosity Functions in M31 and M33
• Exploring the Mass Loss Histories of the Red Supergiants
• ALMA detection of CO rotational line emission in red supergiant stars of the massive young star cluster RSGC1 -- Determination of a new mass-loss rate prescription for red supergiants
• Red Supergiants in M31 and M33 I. The Complete Sample
• Establishing a mass-loss rate relation for red supergiants in the Large Magellanic Cloud
• The Mass-Loss History of the Red Hypergiant VY CMa
• The Period-Luminosity Relations of Red Supergiants in M33 and M31
• The Sample of Red Supergiants in Twelve Low-Mass Galaxies of the Local Group
• The Red Supergiant Binary Fraction as a Function of Metallicity in M31 and M33
• Binary Red Supergiants II: Discovering and Characterizing B-type Companions
• Evolved Massive Stars at Low-metallicity II. Red Supergiant Stars in the Small Magellanic Cloud
• Multiplicity of the red supergiant population in the young massive cluster NGC 330
• Red Supergiants in M31: The Humphreys-Davidson limit at high metallicity
• The impact of winds on the spectral appearance of Red Supergiants
• Is Betelgeuse Really Rotating? Synthetic ALMA Observations of Large-scale Convection in 3D Simulations of Red Supergiants
• The effect of mass loss in models of red supergiants in the Small Magellanic Cloud
• Characterisation of red supergiants in the Gaia spectral range
• A machine-learning photometric classifier for massive stars in nearby galaxies I. The method
• New infrared spectral indices of luminous cold stars: from early K to M-types
• High-resolution spectroscopic study of massive blue and red supergiants in Per OB1
• Red Supergiant Candidates for Multimessenger Monitoring of the Next Galactic Supernova
• An Exceptional Dimming Event for a Massive, Cool Supergiant in M51
• Evolved Massive Stars at Low-metallicity IV. Using 1.6 $\mu$m "H-bump" to identify red supergiant stars: a case study of NGC 6822
• Investigating episodic mass loss in evolved massive stars: I. Spectroscopy of dusty massive stars in ten southern galaxies
• Prospects for Multimessenger Observations of Thorne-Żytkow Objects
• The Infrared Massive Stellar Content of M83
• Physical parameters of red supergiants in dwarf irregular galaxies in the Local Group
• The Great Dimming of the hypergiant star RW Cephei: CHARA Array images and spectral analysis
• On Granulation and Irregular Variation of Red Supergiants
• Long Term Evolution of Surface Features on the Red Supergiant AZ Cyg
• Photometric Classifications of Evolved Massive Stars: Preparing for the Era of Webb and Roman with Machine Learning
• Properties of luminous red supergiant stars in the Magellanic Clouds
• The temperatures of red supergiants in low metallicity environments
• Investigating episodic mass loss in evolved massive stars: II. Physical properties of red supergiants at subsolar metallicity
• The dusty circumstellar environment of Betelgeuse during the Great Dimming as seen by VLTI/MATISSE
• Identification of late-type stars of class I
• Episodic mass loss in the very luminous red supergiant [W60] B90 in the Large Magellanic Cloud
• Imaging the innermost circumstellar environment of the red supergiant WOH G64 in the Large Magellanic Cloud
• The effect of winds on atmospheric layers of red supergiants II. Modelling VLTI/GRAVITY and MATISSE observations of AH Sco, KW Sgr, V602 Car, CK Car and V460 Car
• Investigating episodic mass loss in evolved massive stars: III. Spectroscopy of dusty massive stars in three northern galaxies
• Searching for Galactic Red Supergiants with Gaia RVS Spectra

Cited by in corpus (1)

• A constant upper luminosity limit of cool supergiant stars down to the extremely low metallicity of I Zw 18