Kevin Zahnle

Email: Kevin.J.Zahnle@nasa.gov

Phone: (650)604-0840

Professional Biography

NASA Ames Research Center 1988-present Stanford University 1987-1988 (postdoc) NRC (postdoc) at NASA Ames 1985-1987 Photochemical modeling; geochemical modeling of atmophiles; impact processes (both ab initio modeling and data-driven modeling); impact frequencies; atmospheric escape processes; planetary accretion.

Education

Ph.D. University of Michigan 1985 (Prof. James C. G. Walker)

Research Interests

Dr. Zahnle will be responsible for the studies involving whether impacts created the Martian valley river networks and the runaway greenhouse studies for Mars and Venus-like planets.

Select Publications

K. Zahnle and J. C. G. Walker (1982). “Evolution of solar ultraviolet luminosity.” Rev. Geophys. Space Phys. 20, 280€“292.

K. Zahnle (1986). “Photochemistry of methane and the formation of hydrocyanic acid (HCN) in the Earth’s early atmosphere.” J. Geophys. Res. 91, 2819€“2834.

K. Zahnle, J. Kasting, and J. Pollack (1988). “Evolution of a steam atmosphere during Earth’s accretion.” Icarus 74, 62€“97.

N. Sleep, K. Zahnle, J. Kasting, and H. Morowitz (1989). “Annihilation of ecosystems by large asteroid impacts on the early Earth.” Nature 342, 139€“142.

K. Zahnle (1990). “Atmospheric chemistry by large impacts.” In Global Catastrophes in Earth History, eds. V. Sharpton and P. Ward, G.S.A. Special Paper 247, 271€“288.

K. Zahnle & N. H. Sleep (1997). “Impacts and the early evolution of life.” In Comets and the Origin of Life, P. Thomas, C. Chyba, & C. McKay, eds, Springer-Verlag, pp. 175-208.

N. H. Sleep & K. Zahnle (2001). “Carbon dioxide cycling and implications for climate on ancient Earth.” J. Geophys. Res. 106, 1373-1399.

N. H. Sleep, K. Zahnle and P. S. Neuhoff (2001). “Initiation of clement surface conditions on the earliest Earth.” Proc. Nat. Acad. Sci. 98, 3666-3672.

T. Segura, O.B. Toon, A. Colaprete, & K. Zahnle (2002). “Environmental effects of large impacts on Mars.” Science 298, 1977-1980.

D. C. Catling, C.P. McKay, & K. Zahnle (2001). “Biogenic methane, hydrogen escape, and the irreversible oxidation of the early Earth.” Science 293, 839-843.

Awards and Others

1996: NASA Exceptional Scientific Achievement Medal.
2001: Ames Associate Fellow