 The relative abundances of these three compounds in the largest KBOs is directly related to their surface gravity and ambient temperature, which determines which they can retain.Water ice has been detected in several KBOs, including members of the Haumea family such as , mid-sized objects such as 38628 Huya and 20000 Varuna, and also on some small objects.The presence of crystalline ice on large and mid-sized objects, including 50000 Quaoar where ammonia hydrate has also been detected, may indicate past tectonic activity aided by melting point lowering due to the presence of ammonia.