NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Cosmic Ray Mantle Visibility on Kuiper Belt ObjectsOptically red objects constitute the dynamically cold, old component of the Classical Kuiper Belt (40 - 47 AU) with heliocentric orbits of low eccentricity and inclination. The red colors likely arise from primordial mixed ices processed by irradiation to meters in surface depth over the past four billion years, since the time of giant planet migration and Kuiper Belt stirring, at relatively moderate dosages of 60 gigarads provided by galactic cosmic ray protons and heavier ions. The red cosmic ray mantle is uniformly visible on the cold classical objects beneath a minimally thin eroded layer of more neutrally colored material arising from cumulative effects of heliospheric particle irradiation. The radiation fluxes are lowest in the middle heliospheric region containing the Classical Kuiper Belt and increase from there both towards and away from the Sun. Despite increasing irradiation at various times of solar system history from increases in solar and interstellar ion fluxes, the red object region has apparently never reached sufficiently high dosage levels to neutralize in color the red mantle material. Erosion processes, including plasma sputtering and micrometeroid impacts, act continuously to reduce thickness of the upper neutral crust and expose the cosmic ray mantle. A deeper layer at tens of meters and more may consist of relatively unprocessed ices that can erupt to the surface by larger impacts or cryovolcanism and account for brighter surfaces of larger objects such as 2003 UB313. Surface colors among the Kuiper Belt and other icy objects of the outer solar system are then a function, assuming uniform primordial composition, of relative thickness for the three layers and of the resurfacing age dependent on the orbital and impact history of each object.
Document ID
20070032071
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Cooper, John F.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Hill, Matt E.
(Johns Hopkins Univ. Laurel, MD, United States)
Richardson, J. D.
(Massachusetts Inst. of Tech. Cambridge, MA, United States)
Sturner, S. J.
(Universities Space Research Association Greenbelt, MD, United States)
Date Acquired
August 23, 2013
Publication Date
December 11, 2006
Subject Category
Astrophysics
Meeting Information
Meeting: 2006 American Geophysical Union Conference Fall Meeting
Location: San Francisco, CA
Country: United States
Start Date: December 11, 2006
End Date: December 15, 2006
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available