The environmental dependence of the stellar mass fundamental plane of
  early-type galaxies
  Aims. We investigate the environmental dependence of the stellar mass
fundamental plane (FP$_*$) using the early-type galaxy sample from the Sloan
Digital Sky Survey Data Release 7 (SDSS DR7).
  Methods. The FP$_*$ is calculated by replacing the luminosity in the
fundamental plane (FP) with stellar mass. Based on the SDSS group catalog, we
characterize the galaxy environment according to the mass of the host dark
matter halo and the position in the halo. In halos with the same mass bin, the
color distributions of central and satellite galaxies are different. Therefore,
we calculate FP$_*$ coefficients of galaxies in different environments and
compare them with those of the FP to study the contribution of the stellar
population.
  Results. We find that coefficient $a$ of the FP$_*$ is systematically larger
than that of the FP, but coefficient $b$ of the FP$_*$ is similar to the FP.
Moreover, the environmental dependence of the FP$_*$ is similar to that of the
FP. For central galaxies, FP$_*$ coefficients are significantly dependent on
the halo mass. For satellite galaxies, the correlation between FP$_*$
coefficients and the halo mass is weak.
  Conclusions. We conclude that the tilt of the FP is not primarily driven by
the stellar population.
