Red Supergiant Stars as Cosmic Abundance Probes: KMOS Observations in NGC 6822

Abstract

We present near-IR spectroscopy of red supergiant (RSG) stars in NGC 6822, obtained with the new VLT-KMOS instrument. From comparisons with model spectra in the J-band we determine the metallicity of 11 RSGs, finding a mean value of [Z] = -0.52 $\pm$ 0.21 which agrees well with previous abundance studies of young stars and HII regions. We also find an indication for a low-significance abundance gradient within the central 1 kpc. We compare our results with those derived from older stellar populations and investigate the difference using a simple chemical evolution model. By comparing the physical properties determined for RSGs in NGC 6822 with those derived using the same technique in the Galaxy and the Magellanic Clouds, we show that there appears to be no significant temperature variation of RSGs with respect to metallicity, in contrast with recent evolutionary models.

Accepted for publication in ApJ

References in corpus (9)

• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• The Star Formation Histories of Local Group Dwarf Galaxies I. Hubble Space Telescope / Wide Field Planetary Camera 2 Observations
• Present-day cosmic abundances. A comprehensive study of nearby early B-type stars and implications for stellar and Galactic evolution and interstellar dust models
• A Survey of Local Group Galaxies Currently Forming Stars: III. A Search for Luminous Blue Variables and Other H-alpha Emission-Lined Stars
• Scaling Relations and the Fundamental Line of the Local Group Dwarf Galaxies
• The Molecular Interstellar Medium of the Local Group Dwarf NGC6822
• A New Method for Measuring Metallicities of Young Super Star Clusters
• Quantitative Spectroscopic J-band Study of Red Supergiants in Perseus OB-1
• Radial velocities from VLT-KMOS spectra of giant stars in the globular cluster NGC 6388

Cited by in corpus (32)

• Young stars and ionized nebulae in M83: comparing chemical abundances at high metallicity
• Carbon and oxygen in HII regions of the Magellanic Clouds: abundance discrepancy and chemical evolution
• Massive donors in interacting binaries: effect of metallicity
• Age dating of an early Milky Way merger via asteroseismology of the naked-eye star $\nu$ Indi
• Red Supergiant Stars as Cosmic Abundance Probes. III. NLTE effects in J-band Magnesium lines
• Red Supergiants as Cosmic Abundance Probes: The Sculptor Galaxy NGC 300
• 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
• First stellar spectroscopy in Leo P
• Detailed chemical composition of classical Cepheids in the LMC cluster NGC 1866 and in the field of the SMC
• Euclid: Early Release Observations -- Deep anatomy of nearby galaxies
• Red supergiants in M31 and M33 II. The Mass Loss Rate
• The metallicity and distance of NGC 2403 from blue supergiants
• Multiplicity of the red supergiant population in the young massive cluster NGC 330
• Constraining the population of isolated massive stars within the Central Molecular Zone
• Young LMC clusters: the role of red supergiants and multiple stellar populations in their integrated light and CMDs
• New infrared spectral indices of luminous cold stars: from early K to M-types
• Gas-phase Fe/O and Fe/N abundances in Star-Forming Regions. Relations between nucleosynthesis, metallicity and dust
• 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
• Physical parameters of red supergiants in dwarf irregular galaxies in the Local Group
• Investigating the metallicity dependence of the mass-loss rate relation of red supergiants
• Investigating episodic mass loss in evolved massive stars: II. Physical properties of red supergiants at subsolar metallicity
• MAGIS (Measuring Abundances of red super Giants with Infrared Spectroscopy) project I. Establishment of an abundance analysis procedure for red supergiants and its evaluation with nearby stars
• Red supergiant stars in IC 1613 and metallicity-dependent mixing length in the evolutionary model
• Investigating episodic mass loss in evolved massive stars: III. Spectroscopy of dusty massive stars in three northern galaxies
• Star formation and gas flow history of a dwarf irregular galaxy traced by gas-phase and stellar metallicities
• Red Supergiants in the Milky Way and Nearby Galaxies
• Euclid: Early Release Observations -- The star cluster systems of the Local Group dwarf galaxies IC 10 and NGC 6822
• A machine-learning photometric classifier for massive stars in nearby galaxies II. The catalog
• Locating Red Supergiants in the Galaxy NGC 6822
• The dwarf irregular galaxy NGC 6822. II. Young, intermediate and old stellar populations: comparison between theory and observations
• On the dwarf irregular galaxy NGC 6822. I. Young, intermediate and old stellar populations