  A correction to the Jeans stability criterion due to heat conduction is
established for the case of high temperature gases. This effect is only
relevant for relativistic fluids and includes an additional term due to a
density gradient driven heat flux. The result is obtained by thoroughly
analyzing the exponentially growing modes present in the dynamics of density
fluctuations in the linearized relativistic Navier-Stokes regime. The
corrections to the corresponding Jeans mass and wavenumber are explicitly
obtained and are compared to the non-relativistic and non-dissipative values
using the transport coefficients obtained in the BGK approximation.
