[meteorite-list] Water Detected on Largest Metallic Asteroid in Solar System (Psyche)

[Ron Baalke]

https://www.usgs.gov/news/water-detected-largest-metallic-asteroid-solar-system

Water Detected on Largest Metallic Asteroid in Solar System
USGS
Release Date: October 20, 2016

Scientists have discovered possible evidence for water-rich minerals on 
the surface of the largest metallic asteroid in the solar system, according 
to a study by the U.S. Geological Survey and NASA. 

The asteroid, called Psyche, is 186 miles across and is made of almost 
pure nickel-iron metal. It is thought to be the remnant core of a planetary 
embryo that was mostly destroyed by impacts billions of years ago.

Previous observations of Psyche had shown no evidence for water-rich minerals 
on its surface. However, new observations from the NASA Infrared Telescope 
Facility in Hawaii show evidence for water and/or hydroxyl on its surface. 
Results are published in The Astronomical Journal.

While the source of these water molecules on Psyche remains a mystery, 
scientists propose a few possible mechanisms for their formation. It is 
possible that water-rich minerals detected on Psyche might have been delivered 
to its surface by carbonaceous asteroids that impacted Psyche in the distant 
past.

"We think that Psyche may not be entirely exposed metallic core," 
says Driss Takir, lead author and scientist at the USGS Astrogeology Science 
Center in Flagstaff, Arizona. "What we see might instead have been a 
core-mantle boundary of a differentiated body that was disrupted via impacts. 
Solar radiation is another mechanism that can produce hydroxyl, which 
is a molecule consisting of one oxygen atom and one hydrogen atom, by 
interacting with the surface of Psyche."

"This work underscores how much more we have to learn about asteroids," 
says Laszlo Kestay, Director of the USGS Astrogeology Science Center. 
"It will take more of this kind of careful work with telescopes on Earth, 
and spacecraft visiting asteroids, before we understand what treasures 
await us in space."

Takir is a member of NASA's OSIRIS-REx mission and JAXA's Hayabusa 2 
mission to collect carbonaceous samples from the water-rich asteroids, 
Bennu and Ryugu.

"We are excited to continue studying Psyche, and other water-rich asteroids, 
to give us further insight into the distribution of potential resources 
in space," said Takir.

This research on Psyche is funded by the USGS/NASA Eugene M. Shoemaker 
Fellowship, NASA Planetary Science Division Planetary Geology and Geophysics 
and Solar System Observations Programs.