Instability of rotating Bose stars

Understand

Light bosonic (axion-like) 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 $l \ne 0$ 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.