Theoretical fit of Cepheid light an radial velocity curves in the Large Magellanic Cloud cluster NGC 1866

TL;DR

This study models the light and radial velocity curves of five Cepheids in NGC 1866 to estimate their stellar parameters and distances, supporting a slightly brighter mass-luminosity relation and confirming the cluster's distance.

Contribution

It provides a theoretical framework for fitting Cepheid light and velocity curves to derive stellar parameters and distances in the Large Magellanic Cloud.

Findings

Best fit models yield intrinsic stellar parameters.

Derived distance modulus of 18.56 mag aligns with previous results.

Indicates a slightly brighter mass-luminosity relation than canonical.

Abstract

We present a theoretical investigation of multifilter (U,B,V, I and K) light and radial velocity curves of five Classical Cepheids in NGC 1866, a young massive cluster of the Large Magellanic Cloud. The best fit models accounting for the luminosity and radial velocity variations of the five selected variables, four pulsating in the fundamental mode and one in the first overtone, provide direct estimates of their intrinsic stellar parameters and individual distances. The resulting stellar properties indicate a slightly brighter Mass Luminosity relation than the canonical one, possibly due to mild overshooting and/or mass loss. As for the inferred distances, the individual values are consistent within the uncertainties. Moreover, their weighted mean value corresponds to a distance modulus of 18.56 + - 0.03 (stat) + - 0.1 (syst) mag, in agreement with several independent results in the literature.