Geological Chronicle
Das is an impact crater on the far side of the Moon, situated northwest of the walled plain Chebyshev, with Mariotte lying to its southwest. Measuring 35.95 kilometers in diameter, the crater exhibits a sharp-edged rim free of notable overlying craters. Slumping along its inner walls has dropped toward an uneven interior floor, while the perimeter remains roughly circular with slight outward bulges toward the west and northwest.
Computer simulations suggest that Das was produced by a projectile about 6 kilometers wide striking the surface at 10 kilometers per second at an angle of 70 degrees. This event excavated material to an estimated depth of roughly 3 kilometers, a fraction of the local lunar crustal thickness. Because the excavation did not reach mantle depths, the olivine and magnesium-rich spinel detected within the formation may represent surviving fragments of the impacting asteroid.
High-albedo ejecta extends continuously outward from the rim for nearly two crater diameters before thinning into faint, wispy rays that reach farthest toward the northwest. The presence of this ray pattern places Das within the Copernican system of lunar geological history.
The International Astronomical Union formally adopted the name Das in 1970, honoring Indian solar astronomer Anil Kumar Das.