Strange Stars ’ - have they been discovered ?

Recently there have been controversial claims about the nature of the isolated compact star RXJ1856.5−3754, with one group claiming it to be a strange star (Drake et al., 2002) while the other asserting it to be a normal neutron star (Walter & Lattimer, 2002). The controversy arises mainly due to the distance estimate, which in turn is used to resolve the measured angular diameter, and thus the radiation radius R∞. In this we discuss the theoretical constraints that appear from analysing the usual mass-radius relation alongwith the redshift factors arising from the strong gravity effects and possible lensing. Unless the distance estimate is confirmed independently, without any uncertainty, it is premature to come to any conclusion regarding the nature of this star. Subject headings: star: RXJ1856.5−3754 – strange star – neutron star – equation of state