Two cosmochemists at Arizona State University have made the first-ever measurements of water contained in samples from the surface of an asteroid. The samples came from asteroid Itokawa (our header picture is of Itokawa) and were collected by the Japanese space probe Hayabusa. The team’s findings suggest that similar asteroid impacts early in Earth’s history could have delivered half of our planet’s ocean water.
“We found the samples we examined were enriched in water compared to the average for inner solar system objects,” says Ziliang Jin. A postdoctoral scholar in ASU’s School of Earth and Space Exploratio, is the lead author on the paper reporting the results in the May 1 edition of Science Advances . His co-author is Maitrayee Bose, assistant professor in the School.
“It was a privilege that the Japanese space agency JAXA was willing to share five particles from Itokawa with a U.S. investigator,” Bose says. “It also reflects well on our School.”
The team’s idea of looking for water in the Itokawa samples came as a surprise for the Hayabusa project. In two of the five particles, the team identified the mineral pyroxene.
In terrestrial samples, pyroxenes have water in their crystal structure. The name is derived from from the Ancient Greek words for fire (πυρ) and stranger (ξένος) because they are in volcanic lavas sometimes seen as crystals embedded in volcanic glass. Originally, it was thought they were impurities in the glass, hence the “fire strangers” but instead scientists were able to discover that they were minerals captured & crystallized before the lava erupted. The upper mantle of Earth is composed mainly of olivine and pyroxene.
The NanoSIMS measurements revealed the samples were unexpectedly rich in water. They also suggest that even nominally dry asteroids such as Itokawa may in fact harbor more water than scientists have thought. Read the full story at Science News.
In astrology, the asteroid Itokawa is named for the Japanese scientist Dr. Hideo Itokawa or “Dr. Rocket”. Dr. Itokawa (born July 20, 1912 – February 21, 1999) is the founder of the Japanese Space Program, thus the asteroid is used in astrological charts to highlight astronomical or rocketry discoveries and advances. In our chart, Itokawa is at 05 Cancer (HS) “celebrities conversing at a banquet in their honour” two degrees away from 03 Cancer (HS) in “clouds, there is a source of rain.”
Kudos to Dr. Ziliang Jin and Dr. Maitrayee Bose for the pioneering research.