Department Seminar by Dr. Orkan Umurhan

Solid state ice convection in Pluto’s Sputnik Planum

Dr. Orkan Umurhan, NASA Ames Research Center

Date: Thursday, June 16, 2016
Time: 10:40
Place: EA 409

The New Horizons spacecraft flyby of Pluto revealed a planet full of surprises including a surface active with glaciation and solid-state convection driven by nitrogen ice. In this talk I will present visual and spectroscopic evidence of unsteady buoyant convection in Pluto’s Sputnik Planum as well as the latest results published regarding the nature of this phenomenon on Pluto which depends critically upon the temperature dependent rheology of nitrogen and carbon monoxide. The rest of the talk will focus on current developments on the modeling of temperature dependent viscous convection appropriate to this system. Of central importance is the question of thermal boundary conditions at the base of a convecting nitrogen ice layer as this physical effect directly influences the spatio-temporal quality of emergent cells. I will also discuss how the presence of or lack thereof a liquid water ocean far beneath Pluto’s surface may influence the quality of convection cells. Numerical simulations will be presented to showcase the various theoretical problems currently posed by this most subtle system.

Short bio:

Orkan Umurhan did his undergraduate studies in physics and astrophysics from UCLA. He received his PhD in Astronomy at Columbia. He is primarily an applied mathematician working on problems in astrophysical flows, geophysical flows, chaos, turbulence and the origins of the Solar System. Orkan has co-authored a graduate level textbook on fluid dynamics for physicists that has been released by Springer in June 2016. Orkan’s research career has spanned several institutions including Stanford, The Technion, Tel Aviv University, Queen Mary University of London and University of California, Merced. Orkan joined the New Horizon’s Geology and Geophysics Imaging team in February 2013 and is now employed at NASA Ames Research Center in Mountain View, California working on various topics including geophysical processes and landform evolution modeling on planetary bodies.

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