Jeans instability of a monatomic gas in the presence of thermal radiation

The Jeans instability in magneto-radiative gas dynamics [MRGD] is discussed in the framework of magneto-gas dynamics [MGD] incorporating rotation and viscosity of the medium. The system of the present problem is assumed to adopt the Landau and Lifshitz model. The dispersion relation is obtained with the help of linearized perturbation equations. We find that the Jeans condition remains valid but the expression of the critical Jeans wave number is modified. Owing to the inclusion of radiative effect the sound speed changes which means that the critical wavelength depends on the amount of rate of radiation. We hope that our discussion on the present problem will help to improve our knowledge of interstellar medium [ISM].