Physical parameters of red supergiants in dwarf irregular galaxies in the Local Group

Abstract

Increasing the statistics of evolved massive stars in the Local Group enables investigating their evolution at different metallicities. During the late stages of stellar evolution, the physics of some phenomena, such as episodic and systematic mass loss, are not well constrained. For example, the physical properties of red supergiants (RSGs) in different metallicity regimes remain poorly understood. Thus, we initiated a systematic study of RSGs in dwarf irregular galaxies (dIrrs) in the Local Group. The target selection is based on 3.6 $\mu$m and 4.5 $\mu$m photometry from archival Spitzer Space Telescope images of nearby galaxies. We selected 46 targets in the dIrrs IC 10, IC 1613, Sextans B, and the Wolf-Lundmark-Melotte (WLM) galaxy that we observed with the GTC-OSIRIS and VLT-FORS2 instruments. We used several photometric techniques together with a spectral energy distribution analysis to derive the luminosities and effective temperatures of known and newly discovered RSGs. We identified and spectroscopically confirmed 4 new RSGs, 5 previously known RSGs, and 5 massive asymptotic giant branch (AGB) stars. We added known objects from previous observations. In total, we present spectral classification and fundamental physical parameters of 25 late-type massive stars in the following dIrrs: Sextans A, Sextans B, IC 10, IC 1613, Pegasus, Phoenix, and WLM. This includes 17 RSGs and 8 AGB stars that have been identified here and previously. Based on our observational results and PARSEC evolutionary models, we draw the following conclusions: (i) a trend to higher minimum effective temperatures at lower metallicities and (ii) the maximum luminosity of RSGs appears to be constant at $log$($L/L$${}_{\odot }$) $\approx$ $5.5$, independent of the metallicity of the host environment (up to $[Fe/H]$ $\approx$ $-1$ dex).

arXiv comment22 pages, 17 figures, in press (A&A)

References in corpus (55)

• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• Dwarf Galaxies of the Local Group
• The observed properties of dwarf galaxies in and around the Local Group
• Mass Loss: Its Effect on the Evolution and Fate of High-Mass Stars
• Rotating Massive Main-Sequence Stars I: Grids of Evolutionary Models and Isochrones
• Automated data reduction workflows for astronomy
• PARSEC evolutionary tracks of massive stars up to $350M_{\odot }$ at metallicities 0.0001$\le Z\le$0.04
• Presupernova evolution and explosive nucleosynthesis of rotating massive stars in the metallicity range -3 <=[Fe/H]<= 0
• The Star Formation Histories of Local Group Dwarf Galaxies I. Hubble Space Telescope / Wide Field Planetary Camera 2 Observations
• The Effective Temperature Scale of Galactic Red Supergiants: Cool, But Not As Cool As We Thought
• An empirical formula for the mass-loss rates of dust-enshrouded red supergiants and oxygen-rich Asymptotic Giant Branch stars
• Grids of stellar models with rotation - III. Models from 0.8 to 120 Msun at a metallicity Z = 0.002
• A UBVR CCD Survey of the Magellanic Clouds
• 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
• The Evolution of Massive Stars. I. Red Supergiants in the Magellanic Clouds
• Spitzer SAGE-SMC Infrared Photometry of Massive Stars in the Small Magellanic Cloud
• The wind speeds, dust content, and mass-loss rates of evolved AGB and RSG stars at varying metallicity
• The temperatures of Red Supergiants
• A Survey of Local Group Galaxies Currently Forming Stars: II. UBVRI Photometry of Stars in Seven Dwarfs and a Comparison of the Entire Sample
• The impact of mass-loss on the evolution and pre-supernova properties of red supergiants
• The VLT-FLAMES Tarantula Survey XVI. The optical+NIR extinction laws in 30 Doradus and the photometric determination of the effective temperatures of OB stars
• The luminosities of cool supergiants in the Magellanic Clouds, and the Humphreys-Davidson limit revisited
• Yellow and Red Supergiants in the Large Magellanic Cloud
• Star formation properties in the Local Volume galaxies via $H\alpha$ and FUV fluxes
• Grids of stellar models with rotation IV. Models from 1.7 to 120 Msun at a metallicity Z = 0.0004
• The Araucaria Project: the Local Group Galaxy WLM--Distance and metallicity from quantitative spectroscopy of blue Supergiants
• A WFPC2 Study of the Resolved Stellar Population of the Pegasus Dwarf Irregular Galaxy (DDO 216)
• The Araucaria Project. VLT spectra of blue supergiants in WLM: classification and first abundances
• Shock Breakout and Early Light Curves of Type II-P Supernovae Observed with Kepler
• First Stellar Abundances in the Dwarf Irregular Galaxy Sextans A
• Stellar Populations at the Center of IC 1613
• Luminosities and mass-loss rates of Local Group AGB stars and Red Supergiants
• Red Supergiant Stars as Cosmic Abundance Probes: KMOS Observations in NGC 6822
• An Infrared Census of DUST in Nearby Galaxies with Spitzer (DUSTiNGS), I. Overview
• The blue to red supergiant ratio in young clusters at various metallicities
• The ARAUCARIA Project: VLT-FORS spectroscopy of blue supergiants in NGC 3109 - Classifications, first abundances and kinematics
• Red Supergiants as Cosmic Abundance Probes: The Magellanic Clouds
• An LTE effective temperature scale for red supergiants in the Magellanic clouds
• Radial Velocity of the Phoenix Dwarf Galaxy: Linking Gas and Hi Gas
• A new survey of cool supergiants in the Magellanic Clouds
• Spectral Types of Red Supergiants in NGC 6822 and the Wolf-Lundmark-Melotte Galaxy
• The VLT-FLAMES Tarantula Survey. XXX. Red stragglers in the clusters Hodge 301 and SL 639
• Discrepancies in the ages of young star clusters; evidence for mergers?
• HV 11423: The Coolest Supergiant in the SMC
• Evolutionary models of red supergiants: Evidence for a metallicity-dependent mixing length and implications for Type IIP supernova progenitors
• Physical Properties of Red Supergiants
• Identification of red supergiants in nearby galaxies with mid-IR photometry
• Physical properties of the first spectroscopically confirmed red supergiant stars in the Sculptor Group galaxy NGC 55
• The chemical evolution of IC10
• Quantitative Spectroscopy of Supergiants in the Local Group Dwarf Galaxy IC 1613: Metallicity and Distance
• Identification of dusty massive stars in star-forming dwarf irregular galaxies in the Local Group with mid-IR photometry
• The AGB population in IC 1613 using JHK photometry
• Massive stars in the Sagittarius Dwarf Irregular Galaxy

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• It has to be cool: on supergiant progenitors of binary black hole mergers from common-envelope evolution
• Massive donors in interacting binaries: effect of metallicity
• The Sample of Red Supergiants in Twelve Low-Mass Galaxies of the Local Group
• A new reference catalogue for the very metal-poor Universe: +150 OB stars in Sextans A
• Investigating episodic mass loss in evolved massive stars: I. Spectroscopy of dusty massive stars in ten southern galaxies
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