Fate of initially bound timelike geodesics in spherical boson stars
Year: 2024
Type: article
Abstract: Boson stars are horizonless compact objects and they could possess novel geodesic orbits under the equilibrium assumption, which differ from those in black hole backgrounds. However, unstable boson stars may collapse into black holes or migrate to stable states, resulting in an inability to maintain the initially bound geodesic orbits within the backgrounds of unstable boson stars. To elucidate the fate of initially bound geodesic orbits in boson stars, we present a study of geodesics within the spherical space times of stable, collapsing, and migrating boson stars. We focus on timelike geodesics that are initially circular or reciprocating. We verify that orbits initially bound within a stable boson star persist in their bound states. For a collapsing boson star, we show that orbits initially bound and reciprocating finally either become unbound or plunge into the newly formed black hole, depending on their initial maximal radii. For initially circular geodesics, we have discovered the existence of a critical radius. Orbits with radii below this critical value are found to plunge into the newly formed black hole, whereas those with radii larger than the critical radius continue to orbit around the vicinity of the newly formed black hole, exhibiting nonzero eccentricities. For the migrating case, a black hole does not form. In this case, the reciprocating orbits span a wider radial range. For initially circular geodesics, orbits with small radii become unbound, and orbits with large radii remain bound with nonvanishing eccentricities. This geodesic study provides an approach to investigating the gravitational collapse and migration of boson stars. Published by the American Physical Society 2024
Source: Physical Review Research
Institutions: Lanzhou University, The University of Texas at Austin
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,625
Awards: G1281507003, G1474490597, G1507536813, G1598136356, G1643667426, G2392200583, G2392315045, G2565927577, G2843948999, G291658462, G3418968631, G4415466890, G4866298534, G5190951959, G6506214067, Collaborative Research: Frameworks: The Einstein Toolkit Ecosystem: Enabling fundamental research in the era of multi-messenger astrophysics, G6933418284, Compact Objects and Gravitational Radiation, G7251405481, G7846331539, Compact Objects and Gravitational Radiation, G8805052026, G8981695096
OpenAlex ID: W4401700057