Quark star matter within an extended quasiparticle model

Abstract In this work, we extend the quasiparticle model to include the chemical potential dependence of the coupling constant g and consider the density-dependent bag constant $$B_m$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>B</mml:mi> <mml:mi>m</mml:mi> </mml:msub> </mml:math> in order to satisfy the asymptotic freedom feature. By satisfying the absolutely stable condition at zero temperature, we draw the stability region of the strange quark matter (SQM) and describe the recently discovered pulsars PSR J0952-0607, PSR J2215+5135, PSR J0740+6620, 4U 1702-429, and HESS J1731-347 as quark stars (QSs) within the extended quasiparticle model. In particular, our results indicate that the polytropic index $$\gamma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>γ</mml:mi> </mml:math> of the quark star matter becomes anisotropic with different magnetic field orientation distributions, and $$\gamma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>γ</mml:mi> </mml:math> decreases with the increment of the maximum star mass of QSs at zero temperature or under the density-dependent magnetic fields within quasiparticle model.