Small strange stars and marginally stable orbit in Newtonian theory

Abstract

It is shown that for very rapidly rotating low-mass strange stars the marginally stable orbit is located above the stellar surface. This effect is explained by the very important role of the oblateness of the rotating strange star. The comparison with some ``academic'' examples is presented. This feature is purely Newtonian in its nature and has nothing to do with relativistic marginally stable orbit. The effect is very large and cannot be treated in a perturbative way. It seems that strange stars as very dense self-bound objects are the only possibility in nature to represent these toy models.