To Ngoc Van (crater)
To Ngoc Van is a pit-floored crater on Mercury, named after the Vietnamese artist Tô Ngọc Vân. It was discovered in January 2008 during the first flyby of the planet by MESSENGER spacecraft. Its floor displays an irregularly shaped collapse feature, which is called a central pit. The size of the pit is. Such a feature may have resulted from collapse of a magma chamber underlying the central part of the crater. The collapse feature is an analog of Earth's volcanic calderas.
