Period-change rates in Large Magellanic Cloud Cepheids revisited

ABSTRACT The period-change rate (PCR) of pulsating variable stars is a useful probe changes in their interior structure, and thus evolutionary stages. So far, the PCRs classical Cepheids Large Magellanic Cloud (LMC) have been explored limited sample total population these variables. Here, we use template-based method to build observed-minus-computed (O ? C) period diagrams, from which can derive for by taking advantage long time baseline afforded Digital Access Sky Century @ Harvard light curves, combined with additional data Optical Gravitational Lensing Experiment, MAssive Compact Halo Object project, Gaia’s Data Release 2, some cases All-Sky Automated Survey. From an initial 2315 sources, our provides unprecedented 1303 LMC accurate PCRs, largest any single galaxy, including Milky Way. derived are largely compatible theoretically expected values, as computed team using Modules Experiments Stellar Astrophysics code, well similar previous computations available literature. Additionally, five long-period ($P\,\gt\, 50\, \rm {d}$) sources display cyclic behaviour O C clearly incompatible changes. Finally, on basis large positive PCR two first-crossing Cepheid candidates identified.