Infrared Variability of Carbon Stars in the LMC Observed with NEOWISE-R

TL;DR

This study analyzes infrared variability of over 11,000 carbon stars in the LMC using WISE data spanning 16 years, identifying new Mira candidates and establishing period-magnitude relations to aid future extragalactic studies.

Contribution

It provides the first large-scale infrared variability analysis of LMC carbon stars, including new Mira candidates and period relations in infrared bands.

Findings

Identified 672 Mira-like variables from WISE data.

Discovered 227 new Mira candidates.

Established period-magnitude and period-color relations.

Abstract

We investigate the infrared variability of carbon stars in the Large Magellanic Cloud (LMC). Our sample consists of 11,134 carbon stars identified in both visual and infrared bands. Among these, 1,184 objects are known Mira variables based on the Optical Gravitational Lensing Experiment III (OGLE-III) observations. We study the infrared variability of the entire sample using the Wide-field Infrared Survey Explorer (WISE) photometric data spanning the past 16 years, including the AllWISE multiepoch data and the Near-Earth Object WISE Reactivation (NEOWISE-R) 2024 final data release. We generate light curves using WISE observations in the W1 and W2 bands and compute Lomb-Scargle periodograms for all sample stars. From the WISE light curves, we derive reliable variability parameters for 1,615 objects. Among these, we identify 672 objects exhibiting clear Mira-like variations: 445 of these are previously known Miras from OGLE-III, while 227 are candidates for new Mira variables identified from the WISE data. We establish period-magnitude and period-color relations in both visual and infrared bands for the known Miras and the newly identified candidates from WISE data. We anticipate that these relations will serve as valuable references for studying carbon stars in other galaxies, including the Milky Way.