The Schönberg-Chandrasekhar limit in presence of small anisotropy and modified gravity

Abstract

The Schönberg-Chandrasekhar limit in post main sequence evolution for stars of masses in the range $1.4\lesssim M/M_{\odot }\lesssim 6$ gives the maximum pressure that the stellar core can withstand, once the central hydrogen is exhausted. It is usually expressed as a quadratic function of $1/\alpha$, with $\alpha$ being the ratio of the mean molecular weight of the core to that of the envelope. Here, we revisit this limit in scenarios where the pressure balance equation in the stellar interior may be modified, and in the presence of small stellar pressure anisotropy, that might arise due to several physical phenomena. Using numerical analysis, we derive a three parameter dependent master formula for the limit, and discuss various physical consequences. As a byproduct, in a limiting case of our formula, we find that in the standard Newtonian framework, the Schönberg-Chandrasekhar limit is best fitted by a polynomial that is linear, rather than quadratic, to lowest order in $1/\alpha$.

To appear in MNRAS

References in corpus (11)

• Healthy theories beyond Horndeski
• Exploring gravitational theories beyond Horndeski
• Equation of State of a Dense and Magnetized Fermion System
• Breaking of Vainshtein screening in scalar-tensor theories beyond Horndeski
• Modified gravity inside astrophysical bodies
• Towards Strong Field Tests of Beyond Horndeski Gravity Theories
• Modeling of Magneto-Rotational Stellar Evolution I. Method and first applications
• Modified gravity in the interior of population II stars
• Constraining modified gravity from tidal phenomena in binary stars
• Giant planet formation in Palatini gravity
• The nature of the Schoenberg-Chandrasekhar limit

Cited by in corpus (1)

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