Rapidly rotating compact strange stars

We compute numerical, relativistic models of uni- formly rotating strange stars for the recently proposed QCD- based equation of state (EOS) of strange quark matter (Dey et al. 1998). Static models based on this EOS are characterised by a larger surface redshift than strange stars within the MIT bag model. The frequencies of the fastest rotating configura- tions described by the Dey et al. (1998) model are much higher than those for neutron star models and for the simplest strange star MIT bag model. We determine a number of physical param- eters for such stars and compare them with those obtained for neutron stars. We construct constant baryon mass equilibrium sequences, both normal and supramassive. We find the upper limits on the maximal masses and maximal frequencies of the rotating configurations. We show that the maximum mass limit does not coincide with the stability limit to quasi-radial pertur- bation. Just as for a neutron star model, a supramassive strange star, prior to its collapse to a black hole, increases its spin as it loses angular momentum. We find that for any given baryon mass, the maximal rotating configuration is not Keplerian. A normal and low mass supramassive strange star gaining angular momentum always slows down just before reaching the Keple- rian limit. For a high-mass supramassive strange star sequence, the Keplerian configuration is the one with the lowest rotational frequency in the sequence. The value of T=W for rapidly ro- tating strange stars of any mass is significantly higher than that for ordinary neutron stars. For Keplerian configurations it in- creases as mass decreases. The results are robust for all linear self-bound equations of state.