Monitoring survey of pulsating giant stars in the Local Group galaxies: survey description, science goals, target selection

TL;DR

This survey monitors pulsating giant stars in Local Group dwarf galaxies to study their evolution, mass loss, and contribution to galaxy evolution through long-term optical observations and infrared data integration.

Contribution

It is the first comprehensive optical monitoring survey of LPVs in most Local Group dwarf galaxies, linking stellar evolution to galaxy evolution.

Findings

Identification of long period variable stars in multiple dwarf galaxies.

Quantification of mass loss and dust production in AGB stars.

Mapping of stellar feedback into the interstellar medium.

Abstract

The population of nearby dwarf galaxies in the Local Group constitutes a complete galactic environment, perfect suited for studying the connection between stellar populations and galaxy evolution. In this study, we are conducting an optical monitoring survey of the majority of dwarf galaxies in the Local Group, with the Isaac Newton Telescope (INT), to identify long period variable stars (LPVs). These stars are at the end points of their evolution and therefore their luminosity can be directly translated into their birth masses; this enables us to reconstruct the star formation history. By the end of the monitoring survey, we will have performed observations over ten epochs, spaced approximately three months apart, and identified long period, dust-producing AGB stars; five epochs of data have been obtained already. LPVs are also the main source of dust; in combination with Spitzer Space Telescope images at mid-IR wavelengths we will quantify the mass loss, and provide a detailed map of the mass feedback into the interstellar medium. We will also use the amplitudes in different optical passbands to determine the radius variations of the stars, and relate this to their mass loss.