  The possibility that ions in a helium white dwarf star are in a Bose-Einstein
condensed state has been explored recently. In particular, it has been argued
that the resulting novel quantum liquid has a new kind of quasiparticle
excitation with a phonon-like dispersion relation. We investigate the neutrino
emission rate due to this gapless state and the resulting impact on the total
luminosity of helium white dwarf stars, as a possible observable way of
detecting this exotic phase. If the condensation temperature for the quantum
liquid state, which is currently not known very precisely, turns out to be high
enough, our calculations indicate that neutrino emission due to the gapless
mode would make a large contribution to the total luminosity of the helium
white dwarf stars.
