ions without the presence of water or hydroxyl, so we were puzzled by our observations at first.”
The findings are interesting in the context of a proposed $500 million mission to send a spacecraft to Psyche, currently under review by NASA. Images taken by a spacecraft orbiting Psyche may enable us to distinguish between water and hydroxyl on the surface.
Asteroids are remaining fragments from the formation of the solar system that today orbit the Sun between the orbits of Mars and Jupiter. Most of them fall into two broad categories: those rich in silicates, and those rich in carbon and volatiles. Metallic asteroids such as Psyche are extremely rare, making it a laboratory to study how planets formed.
While the source of this water on Psyche remains a mystery, Reddy and his colleagues propose two possible mechanisms for its formation. “We think the water we see on Psyche might have been delivered to its surface by carbonaceous asteroids that impacted Psyche in the distant past,” says Reddy.
“Our discovery of carbon and water on an asteroid that isn’t supposed to have those compounds supports the notion that these building blocks of life could have been delivered to our Earth early in the history of our solar system,” said Reddy, who discovered similar dark, carbonaceous impactors rich in volatiles on the surface of asteroid Vesta by studying images from NASA’s Dawn mission. Alternatively, the hydroxyl could be the product of solar wind interacting with silicate minerals on Psyche’s surface.
To further explore the hypothesis of carbon and water delivered to protoplanetary bodies by asteroids in the early solar system, the UA is leading NASA’s OSIRIS-REx mission to bring back a sample from carbonaceous asteroid 101955 Bennu in 2023.
Daniel W. Stolte
Video Caption: Movie showing the radar shape model of main belt asteroid (16) Psyche with high (red) and low (blue) areas on its surface. The radar data were acquired with the Arecibo Radio Observatory. New observations of Psyche by the NASA Infrared Telescope Facility on Mauna Kea, Hawai’i, show that its surface is covered with water/hydroxyl. These volatiles are thought to have been delivered via carbonaceous chondrite impactors or by solar wind interacting with the surface. (Movie Credit: James Richardson (PSI)/Shepard et al. 2016)
“Detection of Water and/or Hydroxyl on Asteroid (16) Psyche,” Driss Takir, Vishnu Reddy et al., 2016, Astronomical Journal [http://aj.aas.org, preprint: https://arxiv.org/abs/1610.00802].
Reddy’s research on Psyche is funded by NASA’s Planetary Science Division’s Planetary Geology and Geophysics program.
The joint 48th meeting of the Division for Planetary Sciences (DPS) and 11th European Planetary Science Congress (EPSC) in Pasadena, California, is second time DPS and EPSC have been joined into one meeting. The goal of the joint meeting is to strengthen international scientific collaboration in all areas of planetary science. This is the first time that EPSC, which provides the dissemination platform for the Europlanet 2020 Research Infrastructure, is held outside Europe. For more information, see: https://aas.org/meetings/dps48. Follow: #dpsepsc, @DPSMeeting, @europlanetmedia, and @AAS_Press on Twitter.