Galileo encounter with 951 gaspra: first pictures of an asteroid.
نویسندگان
چکیده
Galileo images of Gaspra reveal it to be an irregularly shaped object (19 by 12 by 11 kilometers) that appears to have been created by a catastrophic collisional disruption of a precursor parent body. The cratering age of the surface is about 200 million years. Subtle albedo and color variations appear to correlate with morphological features: Brighter materials are associated with craters especially along the crests of ridges, have a stronger 1-micrometer absorption, and may represent freshly excavated mafic materials; darker materials exhibiting a significantly weaker 1-micrometer absorption appear concentrated in interridge areas. One explanation of these patterns is that Gaspra is covered with a thin regolith and that some of this material has migrated downslope in some areas.
منابع مشابه
Cratering on Gaspra
eted. The biggest facet exceeds the largest crater (relative to body radius) ever observed on a satellite or expected from Galileo flyby images of 951 Gaspra show a crater population collisional fragmentation models. Facets cannot be successive dominated by fresh craters several hundred meters in diameter crater-forming impacts; later scars would have destroyed earlier and smaller. They must re...
متن کاملInteraction of the Solar Wind with Magnetized Asteroids
RESUME We use a 2-D hybrid code (fluid electrons, particle ions) to simulate the interaction of the solar wind with a magnetized asteroid. The asteroid field is taken as a dipole with different strengths. For a small magnetic moment a whistler wake is generated. Stronger dipoles generate a magnetosonic perturbation. We compare simulation results with the signatures observed by Galileo near Gasp...
متن کاملTest facility for SD2 comet sampler performance improvement
Rosetta Mission is the third cornerstone of the European Space Agency (ESA) scientific program "Horizon 2000". This program derives from the desire to study comets, that are recognized as important objects for scientific research. Our knowledge about comets and asteroids has improved over the last twenty years. The previous mission which tried to reveal the comet secretes were ESA’s Giotto sate...
متن کاملAsteroid Geology from Galileo and NEAR Shoemaker Data
The four asteroids visited by spacecraft, Gaspra, Ida, Mathilde, and Eros, have shapes and surface morphologies dominated by the effects of impact cratering. The presence of impactderived regolith has been inferred on S-class asteroids Gaspra, Ida, and Eros from photometry, morphological features, and subtle color variations related to optical maturation of surface materials. Grooves and ridges...
متن کاملSecular spin dynamics of inner main-belt asteroids
Understanding the evolution of asteroid spin states is challenging work, in part because asteroids have a variety of orbits, shapes, spin states, and collisional histories but also because they are strongly influenced by gravitational and non-gravitational (YORP) torques. Using efficient numerical models designed to investigate asteroid orbit and spin dynamics, we study here how several individ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Science
دوره 257 5077 شماره
صفحات -
تاریخ انتشار 1992