Long Period Variables in the Large Magellanic Cloud from the EROS-2 survey

TL;DR

This study analyzes over 850,000 variable stars in the Large Magellanic Cloud from the EROS-2 survey to identify, classify, and characterize Long Period Variables, providing a comprehensive catalog and insights into their properties.

Contribution

It introduces a new method using the Abbe test for extracting LPVs from large time series datasets and provides a detailed catalog with multi-band data and classifications.

Findings

Catalog of 43,551 LPV candidates in the LMC.

Identification of multiple periods and characterization of star types.

Analysis of period-luminosity and period-amplitude relations.

Abstract

Context. The EROS-2 survey has produced a database of millions of time series from stars monitored for more than six years, allowing to classify some of their sources into different variable star types. Among these, Long Period Variables (LPVs), known to follow sequences in the period-luminosity diagram, include long secondary period variables whose variability origin is still a matter of debate. Aims.We use the 856 864 variable stars available from the Large Magellanic Cloud (LMC) in the EROS-2 database to detect, classify and characterize LPVs. Methods. Our method to extract LPVs is based on the statistical Abbe test. It investigates the regularity of the light curve with respect to the survey duration in order to extract candidates with long-term variability. The period search is done by Deeming, Lomb-Scargle and generalized Lomb-Scargle methods, combined with Fourier series fit. Color-magnitude, period-magnitude and period-amplitude diagrams are used to characterize our candidates. Results. We present a catalog of 43 551 LPV candidates for the Large Magellanic Cloud. For each of them, we provide up to five periods, mean magnitude in EROS-2, 2MASS and Spitzer bands, BE-RE color, RE amplitude and spectral type.We use infrared data to make the distinction between RGB, O-rich, C-rich and extreme AGB stars. Properties of our LPV candidates are investigated by analyzing period-luminosity and period-amplitude diagrams.