  The convective collapse of thin magnetic flux tubes in the photospheres of
sun-like stars is investigated using realistic models of the superadiabatic
upper convection zone layers of these stars. The strengths of convectively
stable flux tubes are computed as a function of surface gravity and effective
temperature. We find that while stars with T$_{eff}\ge$ 5500 K and log $g$$\ge$
4.0 show flux tubes highly evacuated of gas, and hence strong field strengths,
due to convective collapse, cooler stars exhibit flux tubes with lower field
strengths. Observations reveal the existence of field strengths close to
thermal equipartition limits even in cooler stars, implying highly evacuated
tubes, for which we suggest possible reasons.
