Cerenkov radiation and scalar stars

We explore the possibility that a charged particle moving in the gravitational field generated by a scalar star could radiate energy via a recently proposed gravitational Cerenkov mechanism. We prove numerically that this is not possible for stable boson stars. We also show that soliton stars could have Cerenkov radiation for particular values of the boson mass. although the diluteness of the star grows and actual observational possibility decreases for the more usually discussed boson masses. These conclusions diminish, although do not completely rule out, the observational possibility of actually detecting scalar stars using this mechanism, and lead us to consider other forms, such as gravitational lensing.