Stable Hydrogen burning limits in rapidly rotating very low mass objects

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.