An explanation for the gap in the Gaia HRD for M dwarfs

TL;DR

This paper explains a narrow gap in the Gaia Hertzsprung-Russell Diagram for M dwarfs using standard stellar evolution models, attributing it to a specific luminosity function dip caused by 3He mixing during stellar mergers.

Contribution

It provides a novel explanation for the observed gap in the Gaia HRD based on stellar evolution processes involving 3He mixing.

Findings

The gap is explained by a luminosity function dip due to 3He mixing.

Standard stellar models can reproduce the observed gap.

The gap occurs for a narrow mass range of M dwarfs.

Abstract

We show that the recently discovered narrow gap in the Gaia Hertzsprung - Russell Diagram near MG =10 can be explained by standard stellar evolution models and results from a dip in the luminosity function associated with mixing of 3He during merger of envelope and core convection zones that occurs for a narrow range of masses.