A stabilization mechanism for excited fermion-boson stars

Understand

We study numerically the nonlinear stability of {\it excited} fermion-boson stars in spherical symmetry.

• Such compound hypothetical stars, composed by fermions and bosons, are gravitationally bound, regular, and static configurations described within the coupled Einstein-Klein-Gordon-Euler theoretical framework.
• The excited configurations are characterized by the presence in the radial profile of the (complex, massive) scalar field -- the bosonic piece -- of at least one node across the star.
• The dynamical emergence of one such configuration from the accretion of a cloud of scalar field onto an already-formed neutron star, was numerically revealed in our previous investigation.