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arXiv · 2601.19476

On the stability of the objects of limiting compactness: Black hole and Buchdahl star

Soumya Chakrabarti·Chiranjeeb Singha·Naresh Dadhich
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Abstract

In General Relativity, there exist two objects of limiting compactness, one with a null boundary defining the horizon of a black hole and the other with a timelike boundary defining a Buchdahl star. The two are characterized by gravitational energy equal to or half the mass. Since non-gravitational mass-energy is the source of gravitational energy, both of these objects are manifestly stable. We demonstrate in this letter, in a simple and general way, that the equilibrium state defining the object is indeed stable, independent of the nature of the perturbation.

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Soumya Chakrabarti, Chiranjeeb Singha, Naresh Dadhich. 2026-01-27. On the stability of the objects of limiting compactness: Black hole and Buchdahl star. https://arxiv.org/abs/2601.19476

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