Two Asteroids Named for PSI Scientists

July 29, 2008, Tucson - Two asteroids have been named for Planetary Science Institute (PSI) researchers Keith Holsapple, of Seattle, Wash., and David O'Brien, of Tucson, Ariz.

The recently discovered asteroids are located in the inner region of the main asteroid belt, which is between the orbits of Jupiter and Mars.

20360 Holsapple honors Keith A. Holsapple, a PSI Senior Scientist and Professor of Engineering at the University of Washington. He is recognized for his work in modeling the response of planetary and asteroidal material to stress and shock. Holsapple also has developed scaling laws for cratering and has explored the relationship between asteroidal shape, spin rate and internal strength.

21774 O'Brien honors PSI Research Scientist David P. O'Brien for his studies of the collisional evolution of main-belt minor planets and cratering on 951 Gaspra and other objects. 951 Gaspra was the first asteroid visited closely by a spacecraft. O'Brien also was honored for his studies of primordial sculpting of the main asteroid belt during the planetary accretion process.

Edward Bowell, who discovered the asteroids, announced the new designations during the recent Asteroids, Comets, Meteors 2008 conference in Baltimore, Md. Bowell, an astronomer from Lowell Observatory in Flagstaff, Ariz., suggested the asteroids be named for Holsapple and O'Brien, and the names were then approved by the International Astronomical Union.

20360 Holsapple was discovered on May 1, 1998, and 21774 O'Brien on Sept. 3, 1999. They were found during the search for near-earth objects at the Lowell Observatory's Anderson Mesa Station, 12 miles south of Flagstaff.

The Planetary Science Institute is a private, nonprofit corporation founded in 1972 and dedicated to solar system exploration. It is headquartered in Tucson, Arizona.

PSI scientists are involved in numerous NASA and international missions, the study of Mars and other planets, the Moon, asteroids, comets, interplanetary dust, impact physics, the origin of the solar system, extra-solar planet formation, dynamics, the rise of life, and other areas of research. They conduct fieldwork in North America, Australia and Africa. They also are actively involved in science education and public outreach through school programs, children's books, popular science books and art.

The Institute's researchers are based in 15 states, the United Kingdom, Russia, Switzerland and Australia.