  Selk crater is an $\sim$ 80 km diameter impact crater on the Saturnian icy
satellite, Titan. Melt pools associated with impact craters like Selk provide
environments where liquid water and organics can mix and produce biomolecules
like amino acids. It is partly for this reason that the Selk region has been
selected as the area that NASA's Dragonfly mission will explore and address one
of its primary goals: to search for biological signatures on Titan. Here we
simulate Selk-sized impact craters on Titan to better understand the formation
of Selk and its melt pool. We consider several structures for the icy target
material by changing the thickness of the methane clathrate layer, which has a
substantial effect on the target thermal structure and crater formation. Our
numerical results show that a 4 km-diameter-impactor produces a Selk-sized
crater when 5-15 km thick methane clathrate layers are considered. We confirm
the production of melt pools in these cases and find that the melt volumes are
similar regardless of methane clathrate layer thickness. The distribution of
the melted material, however, is sensitive to the thickness of the methane
clathrate layer. The melt pool appears as a torus-like shape with a few km
depth in the case of 10-15 km thick methane clathrate layer, and as a shallower
layer in the case of a 5 km thick clathrate layer. Melt pools of this thickness
may take tens of thousands of years to freeze, allowing more time for complex
organics to form.
