Mid-infrared JWST spectra of carbon Stars in the Large Magellanic Cloud

Sloan, G. C., Aringer, B., Kraemer, Kathleen E., Cami, J., Eriksson, K., Höfner, S., Justtanont, K., Lagadec, E., Marigo, Paola, Matsuura, M. ORCID: https://orcid.org/0000-0002-5529-5593, McDonald, I., Montiel, E. J., Sahai, R. and Zijlstra, A. A. 2026. Mid-infrared JWST spectra of carbon Stars in the Large Magellanic Cloud. The Astrophysical Journal 1002 (2) , 115. 10.3847/1538-4357/ae5a24

PDF - Published Version Available under License Creative Commons Attribution. Download (6MB)

Abstract

Mid-infrared spectra from the Medium Resolution Spectrometer (MRS) on the James Webb Space Telescope have revealed the molecular chemistry of carbon stars in the Large Magellanic Cloud with better resolution and sensitivity than previously possible. Our sample spans a range of dust-production rates and includes three relatively dust-free semiregular variables and six dustier Mira variables. All were observed 15–20 yr earlier with the Infrared Spectrograph on the Spitzer Space Telescope at lower spectral resolution. The new spectra show that the C3 molecule is responsible for a strong absorption band centered at 5.2 μm. CS is clearly present in some of the sample, especially the stars with less dust. HCN also appears to be present. Some of the spectra have changed significantly between the Spitzer epoch and the MRS observations in 2023 and 2024, and in most cases these changes can be attributed to the stellar pulsation cycle. One exception is the disappearance of a dust emission feature at ∼18 μm in one of the Miras. The new spectra reveal a dip centered at ∼10 μm, which could arise either from an unknown carrier or from variable molecular emission to the red and blue. The presence of this spectral structure on the short-wavelength side of the SiC dust emission feature at ∼11.3 μm along with the broad C2H2 band centered at 14 μm raise the possibility that some previously reported detections of weak SiC dust emission in other carbon stars may not be real.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Schools > Physics and Astronomy
Additional Information:	License information from Publisher: LICENSE 1: URL: https://creativecommons.org/licenses/by/4.0/, Type: cc-by
Publisher:	American Astronomical Society
ISSN:	0004-637X
Date of First Compliant Deposit:	7 May 2026
Date of Acceptance:	16 March 2026
Last Modified:	07 May 2026 08:30
URI:	https://orca.cardiff.ac.uk/id/eprint/186839

Actions (repository staff only)

Edit Item