# How Rotation Affects Masses and Ages of Classical Cepheids

## TL;DR

This paper explores how stellar rotation influences the masses and ages of Classical Cepheids, resolving longstanding issues and revealing that rotation extends their lifetimes, affecting their use as cosmic distance markers.

## Contribution

It demonstrates that stellar rotation resolves the Cepheid mass discrepancy and significantly increases their estimated ages, impacting astrophysical models and distance measurements.

## Key findings

- Rotation resolves the Cepheid mass discrepancy.
- Rotation doubles the estimated ages of Cepheids.
- Short-period Cepheids are key indicators for model validation.

## Abstract

Classical Cepheid variable stars are both sensitive astrophysical laboratories and accurate cosmic distance tracers. We have recently investigated how the evolutionary effects of rotation impact the properties of these important stars and here provide an accessible overview of some key elements as well as two important consequences. Firstly, rotation resolves the long-standing Cepheid mass discrepancy problem. Second, rotation increases main sequence lifetimes, i.e, Cepheids are approximately twice as old as previously thought. Finally, we highlight the importance of the short-period ends of Cepheid period distributions as indicators for model adequacy.