|Region||Mare Australe quadrangle|
|Quadrangle||Mare Australe quadrangle|
Playfair is an impact crater in the Mare Australe quadrangle of Mars, located at 78.1°S latitude and 126.2°W longitude. It measures 64.2 kilometers in diameter and was named after Scottish scientist and mathematician John Playfair. The naming was approved in 1973, by the IAU's Working Group for Planetary System Nomenclature.
This picture was taken in the spring season on Mars when the temperature was rising. During the winter, much frost accumulates. When the temperature goes up in the spring, the frost disappears in the thin Martian atmosphere and leaves behind the dark ground. The surface appears covered with dark spots when this defrosting process is occurring.
The dark spots can be seen in some of the pictures below.
Playfair (Martian crater), as seen by CTX camera (on Mars Reconnaissance Orbiter). Dark dots are places where frost has disappeared.
Defrosting going on in Playfair crater, as seen by CTX camera (on Mars Reconnaissance Orbiter). Dark areas are where frost has disappeared thereby showing dark ground. Note: this is an enlargement of the previous image of Playfair crater.