  In this article we discuss some aspects of solar physics from the standpoint
of the so-called chameleon fields (i.e. quantum fields, typically scalar, where
the mass is an increasing function of the matter density of the environment).
Firstly, we analyze the effects of a chameleon-induced deviation from standard
gravity just below the surface of the Sun. In particular, we develop solar
models which take into account the presence of the chameleon and we show that
they are inconsistent with the helioseismic data. This inconsistency presents
itself not only with the typical chameleon set-up discussed in the literature
(where the mass scale of the potential is fine-tuned to the meV), but also if
we remove the fine-tuning on the scale of the potential. Secondly, we point out
that, in a model recently considered in the literature (we call this model
"Modified Fujii's Model"), a conceivable interpretation of the solar
oscillations is given by quantum vacuum fluctuations of a chameleon.
