  M dwarfs host most of the exoplanets in the local Milky Way. Some of these
planets, ranging from sub-Earths to super-Jupiters, orbit in their stars'
habitable zones (HZs), although many likely possess surface environments that
preclude habitability. Moreover, exomoons around these planets could harbor
life for long timescales and thus may also be targets for biosignature surveys.
Here we investigate the potential habitability, stability, and detectability of
exomoons around exoplanets orbiting M dwarfs. We first compile an updated list
of known M-dwarf exoplanet hosts, comprising 109 stars and 205 planets. For
each M dwarf, we compute and update precise luminosities with the Virtual
Observatory spectral energy distribution Analyzer and Gaia DR2 parallaxes to
determine inner and outer boundaries of their HZs. For each planet, we retrieve
(or, when necessary, homogeneously estimate) their masses and radii, calculate
the long-term dynamical stability of hypothetical moons, and identify those
planets that can support habitable moons. We find that 33 exoplanet candidates
are located in the HZs of their host stars and that four of them could host
Moon- to Titan-mass exomoons for timescales longer than the Hubble time.
