Abstract: 
Since the arrival of the JAXA’s Hayabusa2 spacecraft at asteroid Ryugu on June 27, 2018, observations by onboard remote-sensing instruments and landers have provided interesting insights into the features of asteroid Ryugu. The two-times of successful touchdowns have enabled collections of both surface and interior samples of the asteroid, which is an advantage to investigate origin and evolution of the Solar System as well as the surface processes of the asteroid. After the sample return in December 2020, curatorial work on the Ryugu sample will be conducted at JAXA for the first 6 months. Afterward, initial sample analysis will be performed during the following 12 months.

The presence of organic compounds is unknown at this stage, although the low albedo at 0.55 μm may be related to the presence of organic carbon. Thus, the initial sample analysis will be the first opportunity to unveil the distributions and compositions of organic molecules on a C-type asteroid, which lead to our understanding of the Solar System formation and volatile delivery to the Earth.

Organic macromolecules have been identified from various types of small body materials, such as chondritic meteorites, interplanetary dust particles (IDPs), cometary dusts, and Antarctic micrometeorites (AMMs), indicating that they enable our comprehensive understanding of chemical history of the early Solar System. Comparison of organic chemistry in association with mineralogy between meteorites and cometary materials have revealed a blurred boundary between carbonaceous chondrites and comets, implying the material mixing in the early Solar System. Investigation of organic macromolecules in asteroid Ryugu samples will verify the hypothesis and constrain the origin and chemical evolution of building blocks of planets and life as well as the formation of asteroid Ryugu. 

Speaker: Dr Hikaru Yabuta, Hiroshima University.

Speaker bio: 
Hikaru Yabuta obtained her PhD in chemistry from University of Tsukuba in 2002. Her research interest is chemical evolution of organic molecules in Solar System small bodies. She has been devoted to the carbonaceous asteroid sample–return mission, Hayabusa2, as a leader of organic macromolecule analysis team in the mission.

Host: Tony Jia, ELSI.

Date: Fri, 25 September at 15:30 JST (Fri, 25 September 2020 at 06:30 UTC)

Venue: Online