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RED SUPERGIANT STARS AS COSMIC ABUNDANCE PROBES: KMOS OBSERVATIONS IN NGC 6822

Patrick, LR and Evans, CJ and Davies, B and Kudritzki, R-P and Gazak, JZ and Bergemann, M and Plez, B and Ferguson, AMN (2015) RED SUPERGIANT STARS AS COSMIC ABUNDANCE PROBES: KMOS OBSERVATIONS IN NGC 6822. ASTROPHYSICAL JOURNAL, 803 (1). ISSN 0004-637X

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Open Access URL: https://arxiv.org/pdf/1501.07601 (Accepted version)

Abstract

We present near-IR spectroscopy of red supergiant (RSG) stars in NGC 6822, obtained with the new K-band Multi-Object Spectrograph Very Large Telescope, Chile. From comparisons with model spectra in the J-band we determine the metallicity of 11 RSGs, finding a mean value of [Z] = −0.52 ± 0.21, which agrees well with previous abundance studies of young stars and H ii 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 to recent evolutionary models.

Item Type: Article
Uncontrolled Keywords: 0201 Astronomical And Space Sciences, 0305 Organic Chemistry, 0306 Physical Chemistry (Incl. Structural)
Subjects: Q Science > QB Astronomy
Divisions: Astrophysics Research Institute
Publisher: IOP PUBLISHING LTD
Related URLs:
Date Deposited: 10 Apr 2017 12:43
Last Modified: 10 Apr 2017 12:43
DOI or Identification number: 10.1088/0004-637X/803/1/14
URI: http://researchonline.ljmu.ac.uk/id/eprint/6236

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