  We hypothesize that hot Jupiters with inflated sizes represent a separate
planet formation channel,the merging of two low-mass stars. We show that the
abundance and properties of W UMa stars and low mass detached binaries are
consistent with their being possible progenitors. The degree of inflation of
the transiting hot Jupiters correlates with their expected spiral-in life time
by tidal dissipation, and this could indicate youth if the stellar dissipation
parameter Q'* is sufficiently low. Several Jupiter-mass planets can form in the
massive compact disk formed in a merger event. Gravitational scattering between
them can explain the high incidence of excentric, inclined, and retrograde
orbits. If the population of inflated planets is indeed formed by a merger
process, their frequency should be much higher around blue stragglers than
around T Tauri stars.

Solar and Stellar Astrophysics;Earth and Planetary Astrophysics