Delta Scuti Variables

TL;DR

This review discusses recent observational and theoretical advances in the study of Delta Scuti stars, highlighting challenges, methodologies, and future research directions in asteroseismology.

Contribution

It provides a comprehensive overview of recent progress, issues, and strategies in observing and analyzing Delta Scuti variables, including insights from space missions and theoretical developments.

Findings

Identification of challenges in analyzing high-amplitude pulsators

Insights into hybrid and pre-main sequence Delta Scuti stars

Discussion of theoretical models and future research questions

Abstract

We review recent research on Delta Scuti stars from an observer's viewpoint. First, some signposts helping to lead the way through the Delta Scuti jungle are placed. Then, some problems in studying individual pulsators in the framework of asteroseismology are given before a view on how the study of these variables has benefited (or not) from past and present high-precision asteroseismic space missions is presented. Some possible pitfalls in the analysis of data with a large dynamical range in pulsational amplitudes are pointed out, and a strategy to optimize the outcome of asteroseismic studies of Delta Scuti stars is suggested. We continue with some views on "hybrid" pulsators and interesting individual High Amplitude Delta Scuti stars, and then take a look on Delta Scuti stars in stellar systems of several different kinds. Recent results on pre-main sequence Delta Scuti stars are discussed as are questions related to the instability strip of these variables. Finally, some remarkable new theoretical results are highlighted before, instead of a set of classical conclusions, questions to be solved in the future, are raised.