Kevin Zahnle

Contact Information
Title: 
Scientist
Phone: 
(650)604-0840
Email : 
Kevin.J.Zahnle@nasa.gov
Professional Background
Professional Biography: 
NASA Ames Research Center 1988-present
Stanford University 1987-1988 (postdoc)
NRC (postdoc) at NASA Ames 1985-1987

Photochemical modelling; geochemical modelling of atmophiles; impact processes (both ab initio modelling and data-driven modelling); impact frequencies; atmospheric escape processes; planetary accretion.
Education: 
PhD 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.
Other Information
Awards and Other: 
1996: NASA Exceptional Scientific Achievement Medal.
2001: Ames Associate Fellow