Pre-main sequence evolution of low-mass stars in Eddington-inspired Born-Infeld gravity

TL;DR

This paper explores how Eddington-inspired Born-Infeld gravity affects early low-mass star evolution, revealing dependencies on the theory's parameters and central density, and discusses implications for detecting new physics in stars.

Contribution

It provides a detailed analysis of low-mass star evolution in EiBI gravity, highlighting the influence of the theory's parameters and central density on key stellar properties.

Findings

Hayashi tracks shift depending on EiBI parameter sign

Minimum mass for main sequence varies with theory parameters

Maximum mass for fully convective stars is affected by central density

Abstract

We study three aspects of the early-evolutionary phases in low-mass stars within Eddington-inspired Born-Infeld (EiBI) gravity, a viable extension of General Relativity. These aspects are concerned with the Hayashi tracks (i.e. the effective temperature-luminosity relation); the minimum mass required to belong to the main sequence; and the maximum mass allowed for a fully convective star within the main sequence. In all cases we find a dependence of these quantities not only on the theory's parameter, but also on the star's central density, a feature previously found in Palatini $f(R)$ gravity. Using this, we investigate the evolution of these quantities with the (sign of the) EiBI parameter, finding a shift in the Hayashi tracks in opposite directions in the positive/negative branches of it, and an increase (decrease) for positive (negative) parameter in the two masses above. We use these results to ellaborate on the chances to seek for traces of new physics in low-mass stars within this theory.