# On Binary Channels to Anomalous Cepheids

## TL;DR

This study explores how binary star evolution models can better explain the origins of Anomalous Cepheids, suggesting that binary interactions expand the range of possible progenitors beyond single-star models.

## Contribution

It introduces binary evolution scenarios, including mass transfer and mergers, as a new approach to understanding Anomalous Cepheids, extending the parameter space of possible progenitors.

## Key findings

- Binary models allow stars with higher metallicities to pass through the instability strip.
- A wider range of star masses can produce Anomalous Cepheids in binary scenarios.
- Binary interactions may explain the observed properties of Anomalous Cepheids better than single-star models.

## Abstract

Anomalous Cepheids are a rather rare family of pulsating variables preferably found in dwarf galaxies. Attempts to model these variable stars via single-star evolution scenarios still leave space for improvements to better grasp their origin. Focusing on the LMC with its rich population of Anomalous Cepheids to compare against we probe the role binary stars might play to understand the nature of Anomalous Cepheids. The evolution of donors and accretors undergoing Case-B mass transfer along the first red-giant branch as well as merger-like models were calculated. First results show that in binary scenarios a larger range of star masses and metallicities up to Z < 0.008, higher than deemed possible hitherto, enter and pass through the instability strip. If binary stars play a role in Anomalous Cepheid populations, mass donors, mass accretors, or even mergers are potential candidates to counteract constraints imposed by the single-star approach.