ERIK ASPHAUG Professor of Earth & Planetary Sciences Asteroids, comets, impact cratering
		Office: EMS A108 Phone: 831-459-2260 Fax: 831-459-3074 E-mail: easphaug@ucsc.edu		For more information: • Website • Publications (PDF) • Focus on Research

Education and Training

BA, Mathematics and English, Rice University, Houston
PhD, Planetary Sciences (minor in geophysics), University of Arizona, Tucson

Research Interests

Like any planetary scientist, Erik Asphaug is interested in the origin and evolution of the solar system. One focus of his research is the geologic makeup and evolution of asteroids and comets, from which the planets accumulated; despite their ultra-low gravity, these appear to be rubble piles. Another is what happens when asteroids and comets impact planets, forming craters. He also studies larger scale collisions, common during early planet formation, such as the impact believed to have formed the Moon. With Craig Agnor and Quentin Williams of UCSC he is exploring "hit and run" planetary collisions, where bodies of comparable size collide in early planet formation but do not merge. This has led to new ideas both for the early solar system history and for late stage planetary evolution.

Spacecraft have just begun examining the resource-rich, scientifically exciting, and sometimes dangerous near-Earth objects. These "NEOs" are mostly asteroids scattered inwards from the Main Belt, but include dead comets and other relics. Asphaug is leading a UCSC-JPL proposal effort for NASA Discovery called Deep Interior, the mission goal being to acquire a radar data set from close orbit about an asteroid or comet, to image its volumetric interior much like a medical tomographic scan. He is also working on the development of technologies for seismo-mechanical asteroid exploration.

Asphaug uses computer hydrocode techniques to model planetary collisions. For his Ph.D. he helped develop a commonly used explicit brittle fracture model for use in smooth particle hydrodynamics (SPH) impact simulations. Because planetary collisions occur far beyond the scale of any experimental laboratory, we resort to such simulations to research this complex family of processes. For example, numerical experiments revealed the process of hit-and-run collisions, and the results of those simulations are now being connected to meteorite evidence from the first few million years of solar system history, and to oddball planets like Mercury.

Asphaug collaborates with students and other researchers on the coupled topics of Mars landscape and climate evolution. His students work on the perturbation of Mars climate by outflow channels, on the subsurface and atmospheric effects of large-scale impacts, on the evolution of crater lakes, and on the presence of martian alluvial fans which occur almost entirely within the inside rims of impact craters. (What's the connection?) Another student is using supervised classifiers to auto-detect features on the martian surface.

Together with Don Korycansky of UCSC, he is a member of the science team of LCROSS, the Lunar Crater Observation and Sensing Satellite, under development at NASA Ames. LCROSS is a secondary payload, in which a well-instrumented Shepherding Spacecraft observes, up close, what happens when the LRO spent Centaur upper stage crashes into a permanently shadowed, possibly ice-rich region of the Moon, sometime in late 2008.

Teaching Interests

Planetary Science, Comparative Planetology, Planetary Discovery