What can the redshift observed in EXO 0748-676 tell us?
  The mass-radius relations for bare and crusted strange stars are calculated with the bag model. Comparing these relations with the observed one derived from redshift, we address that the conclusion, that EXO 0748-676 can not be a strange star, is incorrect. Various strange star models can show that EXO 0748-676 could have a mass of (1.3 ~ 1.7) M_sun and a radius of (8.4 ~ 11.4) km. It is proposed that some nascent strange stars could be bare and have mass \~ 0.1 M_sun, whereas their masses increase during a long accretion history. 
R.X. Xu (PKU)