A desert planet is a type of terrestrial planet, in which the climate is mostly desert, with little to no natural precipitation. Desert planets outside and inside the Solar System are known to exist, with Mars usually being a prime example of a Desert planet. The term is often used for desert planets which are hospitable for life.
Desert planets are relatively common motif in science fiction.
A recent study has suggested that not only are life-sustaining desert planets possible, they may be more common then earth-like planets. The reason for this prediction is that, when modeled, desert planets had a much larger habitable zone than watery planets.
This same study has suggested that, long ago, Venus may have once been a habitable desert planet and that the same may have been true for Mars, and that life on Mars may exist even in the modern era. (Although this has yet to be determined).
Despite how they are commonly portrayed, a habitable desert planet would probably not have a completely uniform climate. It would likely have some amount of surface water near its poles, although the climate pattern would strongly depend, as for other bodies, on that planet's axial tilt.
Study conduct in 2013 concluded that hot desert planets without runaway greenhouse effect can exist in 0.5 AU around Sun-like stars. It was also concluded in that study that minimum humidity of 1% of is needed to wash off carbon dioxide from atmosphere, but too much water can act as a greenhouse gas itself. Higher atmospheric pressures increase the range of which the water can remain liquid.