Gravitational waves from accretion-induced descalarization in massive scalar-tensor theory

Understand

Many classes of extended scalar-tensor theories predict that dynamical instabilities can take place at high energies, leading to the formation of scalarized neutron stars.

• Depending on the theory parameters, stars in a scalarized state can form a solution-space branch that shares a lot of similarities with the so-called mass twins in general relativity appearing for equations of state containing first-order phase transitions.
• Members of this scalarized branch have a lower maximum mass and central energy density compared to Einstein ones.
• In such cases, a scalarized star could potentially over-accrete beyond the critical mass limit, thus triggering a gravitational phase transition where the star sheds its scalar hair and migrates over to its non-scalarized counterpart.