Titanʹs Snowline

We show that the “snowline” altitude on Titan, above which the condensed nonideal methane–nitrogen phase is solid, is lower (∼14 km) near the equator than at high latitudes (∼19 km). This counterintuitive result derives from the thermodynamic behavior of the binary condensate. The snowline altitude is an operating constraint on future Titan missions where icing would pose a ceiling on atmospheric flight. These snowline altitudes are higher than likely topography, suggesting that optically bright regions on Titan are not due to veneering caused by methane frost deposition.