Instability of rotating Bose stars
Abstract
Light bosonic (axionlike) dark matter may form Bose stars—clumps of nonrelativistic Bose-Einstein condensate supported by self-gravity. We study rotating Bose stars composed of condensed particles with nonzero angular momentum l . We analytically prove that these objects are unstable at arbitrary l ≠0 if particle self-interactions are attractive or negligibly small. They decay by shedding off the particles and transporting the angular momentum to the periphery of the system until a Saturn-like configuration appears: One (or several) spin-zero Bose stars and clouds of diffuse particles orbit around the mutual center. In the case of no self-interactions, we calculate the profiles and dominant instability modes of the rotating stars: numerically at 1 ≤l ≤15 and analytically at l ≫1 . Notably, their lifetimes are always comparable to the inverse binding energies; hence, these objects cannot be considered long-living. Finally, we numerically show that in models with sufficiently strong repulsive self-interactions the Bose star with l =1 is stable.
- Publication:
-
Physical Review D
- Pub Date:
- July 2021
- DOI:
- 10.1103/PhysRevD.104.023504
- arXiv:
- arXiv:2104.00962
- Bibcode:
- 2021PhRvD.104b3504D
- Keywords:
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- General Relativity and Quantum Cosmology;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- Condensed Matter - Statistical Mechanics;
- High Energy Physics - Theory
- E-Print:
- 18 pages, 17 figures