Bullialdus crater and its central peak.

Bullialdus lunar crater. 17 July 2013, 22:00-22:28 LT

The relatively isolated impact lunar crater Bullialdus is found in the western portion of Mare Nubium. This crater has a high outer rim that is circular with the usual subtle polygonal appearance. The inner terraced walls for which this crater is famous for are hidden in darkness. On the other hand the outer ramparts are conspicuous, and highlight a radial pattern of low ridges and valleys.

The illuminated part of the floor of the crater is generally rough with many low rises. In the center of the crater is a formation of several peaks and rises that climb to over a kilometer in height. The sketch shows this prominent peak that comes out of the surrounding shadow simply because of its height.

Klima et al., (2013) showed how the central peak of Bullialdus Crater is significantly enhanced in hydroxyl relative to its surroundings. This is indicative that the peak originated from deep down below the crater as result of the immense impact pressure and heat.

Two smaller but notable craters lie just to the south of the main crater. Bullialdus A lies just to the south-west of Bullialdus, within its ramparts. To the south of Bullialdus A is the slightly smaller Bullialdus B.To the Southwest is the conspicuous but smaller lunar crater Konig. Its shadow suggests a tapering side wall towards the northwest.


References:

R. Klima, J. Cahill, J. Hagerty, D. Lawrence (2013). Remote detection of magmatic water in Bullialdus Crater on the Moon. Nature Geoscience 6, 737–741 (2013) doi:10.1038/ngeo1909