Stable Hydrogen burning limits in rapidly rotating very low mass objects

TL;DR

This paper explores how rapid uniform stellar rotation affects the minimum and maximum mass thresholds for stable hydrogen burning in very low mass stars, revealing new effects and limits.

Contribution

It introduces an analytic model that accounts for rapid rotation and predicts a rotation period limit for stable hydrogen burning in very low mass stars.

Findings

Derived an analytic formula for minimum hydrogen burning mass as a function of rotation speed.

Discovered a maximum stable hydrogen burning mass caused by rapid rotation.

Identified a minimum rotation period (~22 min) below which stars cannot reach the main sequence.

Abstract

We present novel effects of uniform rapid stellar rotation on the minimum mass of stable hydrogen burning in very low mass stars, using an analytic model, and relaxing the assumption of spherical symmetry. We obtain an analytic formula for the minimum mass of hydrogen burning as a function of the angular speed of stellar rotation. Further, we show the existence of a maximum mass of stable hydrogen burning in such stars, which is purely an artefact of rapid rotation. The existence of this extremum in mass results in a minimum admissible value of the stellar rotation period $\sim 22$ min, below which a very low mass object does not reach the main sequence, within the ambits of our model. For a given angular speed, we predict a mass range beyond which such an object will not evolve into a main sequence star.