The beat Cepheids in the Magellanic Clouds: an analysis from the EROS-2 database

Abstract

A number of microlensing dark-matter surveys have produced tens of millions of light curves of individual background stars. These data provide an unprecedented opportunity for systematic studies of whole classes of variable stars and their host galaxies. We aim to use the EROS-2 survey of the Magellanic Clouds to detect and study the population of beat Cepheids (BCs) in both Clouds. BCs pulsating simultaneously in the first overtone and fundamental modes (FO/F) or in the second and first overtone modes (SO/FO) are of particular interest. Using special software designed to search for periodic variables, we have scanned the EROS-2 data base for variables in the typical period range of Cepheids. Metallicities of FO/F objects were then calculated from linear nonadiabatic convective stellar models. We identify 74 FO/F BCs in the LMC and 41 in the SMC, and 173 and 129 SO/FO pulsators in the LMC and SMC, respectively; 185 of these stars are new discoveries. For nearly all the FO/F objects we determine minimum, mean, and maximum values of the metallicity. The EROS data have expanded the samples of known BCs in the LMC by 31%, in the SMC by 110%. The FO/F objects provide independent measures of metallicities in these galaxies. The mean value of metallicity is 0.0045 in the LMC and 0.0018 in the SMC.

10 pages, 7 figures, accepted for publication in A&A

References in corpus (16)

• Limits on the Macho Content of the Galactic Halo from the EROS-2 Survey of the Magellanic Clouds
• Catalogue of [Fe/H] determinations for FGK stars : 2001 edition
• Chemical abundances in LMC stellar populations I. The Inner disk sample Based on observations collected at the VLT UT2 telescope
• The Chemical Enrichment History of the Large Magellanic Cloud
• The Chemical Enrichment History of the Small Magellanic Cloud and Its Gradients
• The MACHO Project LMC Variable Star Inventory: I. Beat Cepheids - Conclusive Evidence for the Excitation of the Second Overtone in Classical Cepheids
• The Infrared Ca II triplet as metallicity indicator
• X-ray Insights Into Interpreting CIV Blueshifts and Optical/UV Continua
• The MACHO Project LMC Variable Star Inventory. VI. The Second-overtone Mode of Cepheid Pulsation From First/Second Overtone (FO/SO) Beat Cepheids
• Detection of Beat Cepheids in M33 and Their Use as a Probe of the M33 Metallicity Distribution
• Chemical evolution of the Small Magellanic Cloud based on planetary nebulae
• Beat Cepheids as Probes of Stellar and Galactic Metallicity
• Observation of periodic variable stars towards the galactic spiral arms by EROS II
• Cepheid models based on self-consistent stellar evolution and pulsation calculations: the right answer?
• The Faint Cepheids of the Small Magellanic Cloud: an evolutionary selection effect?
• Beat Cepheids as Probes of Stellar and Galactic Metallicity: The New AGS Abundances

Cited by in corpus (15)

• Gaia Data Release 3: All-sky classification of 12.4 million variable sources into 25 classes
• The EPOCH Project: I. Periodic variable stars in the EROS-2 LMC database
• The VMC Survey. V. First results for Classical Cepheids
• Gaia Data Release 3: Cross-match of Gaia sources with variable objects from the literature
• The VMC Survey - X. Cepheids, RR Lyrae stars and binaries as probes of the Magellanic System's structure
• Milky Way metallicity gradient from Gaia DR2 F/1O double-mode Cepheids
• Eclipsing binary stars in the Large Magellanic Cloud. Results from the EROS-2, OGLE and VMC surveys
• The Baade-Wesselink p-factor applicable to LMC Cepheids
• Multi-Periodic Oscillations in Cepheids and RR Lyrae-Type Stars
• Properties of M31. III: Candidate Beat Cepheids from PS1 PAndromeda Data and Their Implication on Metallicity Gradient
• A Novel, Fully Automated Pipeline for Period Estimation in the EROS 2 Data Set
• Double-mode Cepheids in M31
• Double-Mode Radial Pulsations among RR Lyrae Stars
• The CoRoT discovery of a unique triple-mode cepheid in the galaxy
• Double Mode Cepheids from the Zwicky Transient Facility Survey