Minimum main sequence mass in quadratic Palatini f (R ) gravity
Abstract
General relativity yields an analytical prediction of a minimum required mass of roughly ∼0.08  0.09 M_{⊙} for a star to stably burn sufficient hydrogen to fully compensate photospheric losses and, therefore, to belong to the main sequence. Those objects below this threshold (brown dwarfs) eventually cool down without any chance to stabilize their internal temperature. In this work we consider quadratic Palatini f (R ) gravity and show that the corresponding Newtonian hydrostatic equilibrium equation contains a new term whose effect is to introduce a weakening/strengthening of the gravitational interaction inside astrophysical bodies. This fact modifies the general relativity prediction for this minimum main sequence mass. Through a crude analytical modeling we use this result in order to constraint a combination of the quadratic f (R ) gravity parameter and the central density according to astrophysical observations.
 Publication:

Physical Review D
 Pub Date:
 August 2019
 DOI:
 10.1103/PhysRevD.100.044020
 arXiv:
 arXiv:1906.04629
 Bibcode:
 2019PhRvD.100d4020O
 Keywords:

 General Relativity and Quantum Cosmology;
 Astrophysics  Solar and Stellar Astrophysics
 EPrint:
 9 pages, revtex41 style. v2: some footnotes and references added. Version accepted for publication in Phys. Rev. D