The Local Group Galaxy IC1613 and its Asymptotic Giant Branch Variables

Abstract

JHKs photometry is presented from a three-year survey of the central regions of the Local Group dwarf irregular galaxy IC1613. The morphologies of the colour-magnitude and colour-colour diagrams are discussed with particular reference to the supergiants and M- and C-type asymptotic giant branch (AGB) stars. Mean JHKs magnitudes, amplitudes and periods are given for five O-rich and nine C-rich Mira variables for which bolometric magnitudes are also estimated. A distance of 750 kpc ($(m-M{)}_0=24.37\pm 0.08$ mag) is derived for IC1613 by fitting a period-luminosity relation to the C-rich Miras. This is in agreement with values from the literature. The AGB stars exhibit a range of ages. A comparison with theoretical isochrones suggests that four luminous O-rich Miras are as young as $2\times 10^8$ yrs. One of these has a lithium absorption line in its spectrum, demonstrating that it is undergoing hot bottom burning (HBB). This supports the idea that HBB is the cause of the high luminosity of these AGB stars, which puts them above the fundamental period-luminosity (PL) relation. Further studies of similar stars, selected from their positions in the PL diagram, could provide insight into HBB. A much fainter, presumed O-rich, Mira is similar to those found in Galactic globular clusters. The C Miras are of intermediate age. The O-rich variables are not all recognized as O-rich, or even as AGB stars, on the basis of their J-Ks colour. It is important to appreciate this when using near-infrared surveys to classify AGB stars in more distant galaxies.

17 pages, 13 figures, 8 tables (1 online only) accepted for publication in MNRAS

References in corpus (17)

• The UKIRT Infrared Deep Sky Survey (UKIDSS)
• The Catalina Surveys Periodic Variable Star Catalog
• The UKIRT Wide Field Camera ZYJHK Photometric System: Calibration from 2MASS
• Evidence for TP-AGB stars in high redshift galaxies, and their effect on deriving stellar population parameters
• Spitzer SAGE survey of the Large Magellanic Cloud II: Evolved Stars and Infrared Color Magnitude Diagrams
• Near-Infrared Photometry of Carbon Stars
• The ACS LCID project. X. The Star Formation History of IC 1613: Revisiting the Over-Cooling Problem
• AGB Stars in the Fornax Dwarf Spheroidal Galaxy
• An Infrared Census of DUST in Nearby Galaxies with Spitzer (DUSTiNGS), I. Overview
• Winds of low-metallicity OB-type stars: HST-COS spectroscopy in IC1613
• Carbon-Rich Mira Variables: Kinematics and Absolute Magnitudes
• Asymptotic Giant Branch Stars in the Phoenix Dwarf Galaxy
• Stellar Content and Recent Star Formation History of the Local Group Dwarf Irregular Galaxy IC1613
• A Spitzer IRAC Census of the Asymptotic Giant Branch Populations in Local Group Dwarfs. II. IC 1613
• The white dwarf cooling sequence of 47 Tucanae
• The AGB population in IC 1613 using JHK photometry
• Evidence for Photometric Contamination in Key Observations of Cepheids in the Benchmark Galaxy IC 1613

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