A search of periodic variable stars in the LMC by JWST photometry

TL;DR

This study demonstrates JWST's capability to detect and analyze various types of periodic variable stars in the crowded fields of the LMC, deriving period-luminosity relations and assessing detection limits.

Contribution

It provides the first assessment of JWST's sensitivity and feasibility for variable star detection in dense stellar environments, including new PLRs and detection threshold analysis.

Findings

Identified 304 periodic variables in the LMC using JWST data.

Derived period-luminosity relations consistent with previous studies for some variables.

Quantified detection limits and the impact of observational cadence on low-amplitude variable detection.

Abstract

Based on high-resolution near-infrared photometric data from the James Webb Space Telescope (JWST) targeting the Large Magellanic Cloud (LMC), this study attempts to evaluate the feasibility and sensitivity limits of variable star detection in crowded stellar fields. Through light curve analysis, we identified a total of 304 periodic variable stars, including 71 EW-type eclipsing binaries, 7 EA-type eclipsing binaries, 177 rotational variables, 38 $\delta$ Scuti (DSCT) stars, and 12 RR Lyrae stars. Period--luminosity relations (PLRs) were derived for EW-type eclipsing binaries, DSCT stars, and RR Lyrae stars. The PLRs for EW-type and RR Lyrae stars are in good agreement with previous studies, while the PLR zero point for DSCT stars appears systematically fainter by approximately 0.15--0.30 mag. Our PLRs exhibit low dispersion and are minimally affected by crowding. We analyzed the capability of JWST archival data to detect low-amplitude variables and found that only stars with amplitudes greater than approximately 0.05 mag can be reliably detected. Through simulations, we quantified how increasing the number of photometric epochs improves the detectability of low-amplitude, low signal-to-noise ratio variables. Despite current limitations in observational cadence, JWST demonstrates unique advantages in detecting short-period eclipsing binaries, rotational variables, and high-amplitude pulsators. Its exceptional spatial resolution enables high-precision PLR calibrations, offering new opportunities for future studies in variable star astrophysics and extragalactic distance measurements.