Scientists Study Surface Composition of Asteroid 2004 BL86 During Close Flyby

[Rick]

PSI Scientists Study Surface Composition of Asteroid 2004 BL86 During Close Flyby of Earth

"Our observations show that this asteroid has a spectrum similar to V-type asteroids," said Reddy. "V-type asteroids are basalt, similar in composition to lava flows we see in Hawai'i. The principal source of V-type asteroids is thought to be ancient basin-forming impacts on the south pole of the large, main-belt asteroid (4) Vesta. These impacts gave rise to the Vesta asteroid family spanning the inner part of the main asteroid belt, and some of those fragments in turn were transported to Earth-crossing orbits." Vesta was the first target of NASA Dawn mission.

More: http://www.psi.edu/news/ceresopnav2

[Rick]

Vesta's Potassium-to-Thorium Ratio Reveals Hot Origins

Studies of materials on the surface of Vesta offer new evidence that the giant asteroid is the source of howardite, eucrite and diogenite (HED) basaltic meteorites, supporting current models of solar system evolution and terrestrial planet formation, a new paper by Planetary Science Institute researcher Tom Prettyman says.

Prettyman, a senior scientist at the Planetary Science Institute, and co-authors determined the globally averaged concentrations of radioactive elements potassium (K) and thorium (Th) on Vesta's surface using data from the Gamma Ray and Neutron Detector (GRaND) instrument aboard NASA's Dawn spacecraft.

PSI Postdoctoral Research Scientist Yuki Yamashita and Senior Scientist Bob Reedy were coauthors on the paper "Concentrations of Potassium and Thorium within Vesta's Regolith" that appears in the Icarus Special Issue on Vesta's Composition. 

"The K and Th content is important because together these elements provide constraints on the composition of materials from which Vesta was made and conditions in the early solar system," Prettyman said. The K/Th ratio of Vesta is very similar to that of the HED meteorites and distinct from other basaltic meteorites, which strongly supports connection between Vesta and the HEDs. 

More: https://www.psi.edu/news/vestak-th