Procyon A

The Procyon System is located about 11.4 light-years from our Sun, Sol. Procyon A, or Alpha Canis Minoris A, is the brightest and most easily located naked-eye star of the Constellation Canis Minor (the Smaller Dog). Procyon is also the upper left member of the "Winter Triangle", whose other components are Sirius (Alpha Canis Minoris) at lower left and Betelgeuse (Alpha Orionis) at right center. (http://www.astro.uiuc.edu/projects/sow/procyon.html) Procyon A …

…the thick, hot atmosphere. Since the water never left the planet and it just evaporated into the atmosphere, it means its always been there but Mikros is usually never cool enough for the water vapor to condense. However at this time once a year the temperature is cool enough for water (condenses at 0 deg. Celsius) and sulfuric acid (below 175 o C). The surface temperature is also cool enough so that the liquid doesn't instantly evaporate.