Hydrogen Burning in Low Mass Stars Constrains Alternative Gravity
  Theories
  The most general scalar-tensor theories of gravity predict a weakening of the
gravitational force inside astrophysical bodies. There is a minimum mass for
hydrogen burning in stars that is set by the interplay of plasma physics and
the theory of gravity. We calculate this for alternative theories of gravity,
and find that it is always significantly larger than the general relativity
prediction. The observation of several low mass Red Dwarf stars therefore rules
out a large class of scalar-tensor gravity theories, and places strong
constraints on the cosmological parameters appearing in the effective field
theory of dark energy.
