Speed of sound in hybrid stars and the role of bag pressure in the emergence of special points on the M -R variation of hybrid stars

We compute the hybrid star (HS) properties with the help of Maxwell construction. For the purpose we choose a fixed hadronic model and four different forms of MIT bag model for the quark phase. We investigate thoroughly the effects of the different parameters of the bag model on the speed of sound in HS matter and the structural properties of HSs in the light of the various recent constraints on them from astrophysical observations. We also examine the importance of each parameter involved in these four forms of bag model in the context appearance of special points (SPs) in the mass-radius (M -R ) variation of HSs. We find that among all these parameters the bag pressure play the most significant role in the emergence of the SPs in the M -R dependence of HSs.