# Convection physics and tidal synchronization of the subdwarf binary NY Virginis

## TL;DR

This paper investigates the discrepancy between observed tidal synchronization in the subdwarf binary NY Virginis and theoretical models, exploring whether extended convective cores or alternative convection treatments can explain the synchronization.

## Contribution

It introduces a parametric study of sdB models with extended convective cores and discusses the potential role of non-MLT convection in tidal synchronization.

## Key findings

- Standard models cannot explain the observed synchronization.
- Extended convective cores alone do not account for synchronization.
- Non-MLT convection treatments might be necessary for accurate modeling.

## Abstract

Asteroseismological analysis of NY Vir suggests that at least the outer 55 per cent of the star (in radius) rotates as a solid body and is tidally synchronized to the orbit. Detailed calculation of tidal dissipation rates in NY Vir fails to account for this synchronization. Recent observations of He core burning stars suggest that the extent of the convective core may be substantially larger than that predicted with theoretical models. We conduct a parametric investigation of sdB models generated with the Cambridge STARS code to artificially extend the radial extent of the convective core. These models with extended cores still fail to account for the synchronization. Tidal synchronization may be achievable with a non-MLT treatment of convection.