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Illuminated distribution of dust and rocks

This is an example of a large rock with a small rock partially filled by a regolith (center) above it. This image shows various fragment sizes, approximately 4 meters wide, taken by the Hayabusa2 optical navigation camera taken near the MINERVA-II landing site (Sugita et al. 2019). Credit: ISAS / JAXA, University of Tokyo.

A new analysis of the Hayabusa2 data on the asteroid Ryugu reveals that much of the surface reflects and scatters light in a manner consistent with laboratory studies of carbonaceous chondrite meteorites. In this study, we pay particular attention to the data taken by Ryugu against the spacecraft and the Sun, and utilize the measurements and observations of Hayabusa2’s near-infrared spectrometer NIRS3 and the optical navigation camera ONC. Deborah Domingue, Deputy Director and Senior Scientist at PSI, led the work. this is, Planetary Science JournalIncludes, and PSI researchers Faith Villas and Lucille Le Colle.


In June 2018, the Hayabusa 2 mission of the Aerospace Research and Development Organization (JAXA) rendezvous with the near-earth asteroid Ryugu. The spacecraft is tasked with studying and sampling this example from the early solar system, and is an uncomfortable object that could one day cross the path of the Earth. (Currently, no object has been identified as a risk to Earth.)

Hayabusa2 studied Ryugu with both a camera that takes pictures like a mobile phone and a spectrometer that diffuses light into various colors like a prism to create a rainbow. This data can be used to understand the different materials that make up an asteroid and the size of the materials.

NIRS3 and ONC have revealed that Ryugu is a dark object made of rubble of various sizes, but has a similar composition throughout and is very similar to carbonic chondrite meteorites. “The image of Ryugu shows a very rough surface, like pebbles on a rocky beach. Our spectral analysis also shows that it also contains finer particle components (think dust). Shows, “said Dominge.

Ryugu against Hayabusa2: A heavily illuminated distribution of dust and rocks

This is another example of a larger rock partially filled with finer regoliths. This is a Type 2 rock with a smoother surface and a thinner layered structure (Sugita et al. 2019). The width of the image taken by the optical navigation camera is about 80 meters. Credit: ISAS / JAXA, University of Tokyo.

This data was obtained under very special conditions, with the spacecraft turning the sun backwards and Ryugu shining brightly in front of the instrument. This alignment is called the opposite. Ryugu was particularly well illuminated because the asteroid is on the other side of the spacecraft from the Sun, enhancing the specific effect of dust interacting with light. The amount of dust present does not impress those who have old, dusty barns, but it was enough to get the attention of these researchers. “The Mobile Asteroid Surface Scout (MASCOT) lander did not see evidence of dust, but two sampling activities showed evidence of dust and a fragile surface. The presence and abundance of dust Under discussion. Our analysis fails. Under the “some dust” side of the discussion, “Dominge said.

The MASCOT was one of the three small robots that Hayabusa2 installed to search for Ryugu.This German aerospace lander explored autonomously for 17 hours and found a very porous surface like pumice, but not. Dust..

Understanding Ryugu is becoming increasingly difficult due to its complexity. The area studied at the opposition looked uniform, but this dataset does not describe the entire asteroid. Throughout its long history, asteroids have experienced heating and radiation from the Sun, and countless collisions with large and small objects. Each interaction leaves its own trace. “The surface of Ryugu is complex,” said Dominge. “There are fluctuations, and these fluctuations are the result of non-uniform interactions with the space environment, from micro to macro scale effects, in addition to changes from the sun.”

It’s easy to imagine that every snowflake is different, but in reality, every asteroid is also different, showing its own composition, weathering, and impact patterns.

This work appears in Planetary Science Journal Titled “162173 Spectral Properties of Ryugu’s Surface from NIRS3 Opposite Observations”, it is only part of Ryugu’s story. This treatise is part of two companion publications, one led by Dominge and one led by Japanese colleague Yakota Yasuhiro, highlighting the team’s efforts to decipher the physical properties of Ryugu. Water surface..


Japanese spacecraft releases rover to asteroid in final mission


For more information:
Deborah Domingue et al, 162173 Ryugu surface spectrophotometric characteristics from NIRS3 counter-observations, Planetary Science Journal (2021). DOI: 10.3847 / PSJ / ac14bb

Quote: Survey of the asteroid Ryugu against Hayabusa2: Glittering dust obtained from https://phys.org/news/2021-09-asteroid-ryugu-opposition-hayabusa2- on September 2, 2021. And rock distribution (September 2, 2021) starkly.html

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