'Mini psyches' give insights into mysterious metal-rich near-Earth asteroids

Artist impression of a close flyby the near-Earth asteroid 1986 DA. NASA Infrared Telescope Facility has confirmed that the asteroid contains 85% of the metal. Astronomers have also confirmed this. Credit: Addy Graham/University of Arizona
Although rare near-Earth asteroids that are metal-rich, called NEAs, offer the intriguing possibility of iron, nickel, and cobalt being mined on Earth or in Space.

The Planetary Science Journal published new research that examined two metal-rich asteroids from our cosmic backyard. It aims to provide more information about their origins, compositions, and relationships with meteorites on Earth.

The metal-rich NEAs are thought to have been created by the destruction of the cores early in the history of the solar system. However, little is known about them. Vishnu Reddy, University of Arizona planetary science associate, led a team of students who studied asteroids 1986 DA (and 2016 ED85) and found that their spectral signatures were very similar to that of asteroid 16 Psyche. This is the largest body with a high level of metal content in the solar system. NASA's Psyche mission is focused on Psyche, which is located in the main asteroid Belt between Jupiter and Mars, rather than near Earth.

Juan Sanchez, a lead author and based at The Planetary Science Institute, stated that "our analysis shows both NEAs surface with 85% metal, such as iron or nickel, and 15% silicate material which is basically rock." These asteroids look similar to some stony iron meteorites like mesosiderites on Earth.

For decades, astronomers have speculated about the composition of Psyche's surface. They hope to find specific meteorites similar to Psyche's surface by studying NEAs rich in metals.

Reddy, the principal investigator for the NASA grant that funded this work, stated, "We started a compositional study of the NEA populace in 2005 when I was a graduate students with the goal to identify and characterize rare NEAs like these metal-rich asteroids." It is gratifying to have found these "mini Psyches" so close to Earth.

Adam Battle, a coauthor of the paper, is one of three graduate students from the Lunar and Planetary Laboratory, Theodore Kareta, and David Cantillo who are undergraduates in the Department of Geosciences.

The paper also examined the mining potential for 1986 DA. It found that the amount iron, nickel, and cobalt that could exist on an asteroid would be greater than the global reserves.

Asteroid families are a group of small asteroids with similar orbital paths and compositions that is formed when an asteroid is destroyed.

To identify four possible asteroid families, the team used orbits and compositions of asteroids 1986 DA (and 2016 ED85) to determine the locations of four possible asteroid families. This region is the home to the largest concentration of small bodies in our solar system. This is also the area where 16 Psyche, the largest known metallic asteroids, are located.

Cantillo stated that the two'mini Psyches,' although they are likely fragments of a large metallic asteroid within the main belt, and not 16 Psyches themselves. It's possible that some iron and stony iron meteorites found on Earth may have come from the same region of the solar system."

Continue reading Study provides a more comprehensive view of the massive asteroid Psyche

Juan A. Sanchez et. al., Physical Characterization of Metallic-rich Near-Earth Asteroids 6178 (1986 DA and 2016 ED85), The Planetary Science Journal (2021). Information from The Planetary Science Journal Juan A. Sanchez et. al., Physical Characterization of Metallic-rich Near-Earth Asteroids (6178) (1986 DA and 2016 ED85), (2021). DOI: 10.3847/PSJ/ac235f