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Paper: |
Infrared Molecular Bands of Carbon-Rich Stars in Nearby Galaxies |
Volume: |
378, Why Galaxies Care About AGB Stars: Their Importance as Actors and Probes |
Page: |
450 |
Authors: |
Matsuura, M.; Sloan, G.C.; Zijlstra, A.A.; Wood, P.R.; Harris, J.G; Bernard-Salas, J.; van Loon, J.Th.; Whitelock, P.A.; Menzies, J.W. |
Abstract: |
We have obtained infrared spectra of carbon stars in four nearby galaxies – the Large and Small Magellanic Clouds, the Sagittarius dwarf spheroidal galaxy, and the Fornax dwarf spheroidal galaxy. These stars were observed using the Infrared Spectrometer (IRS) onboard the Spitzer Space Telescope which covers 5 to 35 μm, and the Infrared Spectrometer And Array Camera (ISAAC) on the Very Large Telescope which covers the 3 μm region. HCN, CH and C2H2 bands are identified in the spectra. We found that C2H2 bands are prominent features at 3–15 μm among extragalactic carbon stars, which is not always the case for Galactic carbon stars. We argue that the difference is caused by systematically high C/O ratios in low-metallicity environments. |
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