Thermodynamic equilibrium conditions for mass varying particle structures

The thermodynamic equilibrium conditions for compact structures composed by mass varying particles are discussed assuming that the so-called dynamical mass behaves like an additional extensive thermodynamic degree of freedom. It then follows that, such weakly interacting massive particles can form clusters of non-baryonic matter or even astrophysical objects that, at cosmological scales, are held together by gravity and by the attractive force mediated by a background scalar field. The equilibrium conditions for resultant static, spherically symmetric objects of uniform energy density are derived for the case where the particles share essential features with the mass varying mechanism in the context of cosmological scenarios. Physical solutions which result in stable astrophysical lumps are obtained and discussed.