Determining the seismic age of the young open cluster $\alpha$ Per using $\delta$ Scuti stars

TL;DR

This study uses seismic analysis of $\delta$ Scuti stars in the $\alpha$ Per cluster to estimate its age more accurately, demonstrating the effectiveness of space asteroseismology in cluster dating.

Contribution

It introduces a new seismic method for constraining the age of young open clusters using $\delta$ Scuti stars and the MultiModes code for pulsation analysis.

Findings

Estimated cluster age between 96 and 100 Myr

Improved accuracy over previous age determination techniques

Validated space asteroseismology as a tool for cluster dating

Abstract

In this work we aim at constraining the age of the young open cluster Melotte 20, known as $\alpha$ Per, using seismic indices. The method consists of the following steps: 1) Extract the frequency content of a sample of stars in the field of an open cluster. 2) Search for possible regularities in the frequency spectra of $\delta$ Scuti candidates, using different techniques, such as the Fourier transform, the autocorrelation function, the histogram of frequency differences and the \'echelle diagram. 3) Constrain the age of the selected stars by both the physical parameters and seismic indices by comparing them with a grid of asteroseismic models representative of $\delta$ Scuti stars. 4) Find possible common ages between these stars to determine the age of the cluster. We performed the pulsation analysis with MultiModes, a rapid, accurate and powerful open-source code, which is presented in this paper. The result is that the age of $\alpha$ Per could be between 96 and 100 Myr. This is an improvement over different techniques in the past. We therefore show that space astroseismology is capable of taking important steps in the dating of young open clusters.