A Sun-like star orbiting a boson star

TL;DR

This paper proposes that a Sun-like star orbiting a dark object, observed by GAIA, can be explained by the presence of a boson star rather than a black hole, offering a new way to test compact object theories.

Contribution

It demonstrates that the observed star orbit can be explained by a boson star, challenging the black hole interpretation and suggesting a new avenue for testing fundamental physics.

Findings

The orbital dynamics are consistent with a boson star model.

Future measurements can distinguish between black holes and boson stars.

Boson stars can form stable two-body systems with Sun-like stars.

Abstract

The high-precision astrometric mission GAIA recently reported the remarkable discovery of a Sun-like star closely orbiting a dark object, with a semi-major axis and period of $1.4\, \rm{AU}$ and $187.8$ days respectively. While the plausible expectation for the central dark object is a black hole, the evolutionary mechanism leading to the formation of such a two-body system is highly challenging. Here, we challenge the scenario of a central black hole and show that the observed orbital dynamics can be explained under fairly general assumptions if the central dark object is a stable clump of bosonic particles of spin-0, or spin-1, known as a boson star. We further explain how future astrometric measurements of similar systems will provide an exciting opportunity to probe the fundamental nature of compact objects and test compact alternatives to black holes.