Characterization of the MASCOT landing area by Hayabusa2

¹ Luleå University of Technology, 98128 Kiruna, Sweden
e-mail: stefanus.schroder@ltu.se
² Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa 252-5210, Japan
³ Center for Data Science, Ehime University, Matsuyama, Ehime 790–8577, Japan
⁴ Kochi University, Kochi 780-8520, Japan
⁵ Instituto de Astrofísica de Canarias, University of La Laguna, 38205 La Laguna, Tenerife, Spain
⁶ Planetary Science Institute, Tucson, AZ 85719-2395, USA
⁷ University of Tokyo, Bunkyo, Tokyo 113-0033, Japan
⁸ Rikkyo University, Toshima, Tokyo 171-8501, Japan
⁹ University of Aizu, Fukushima 965-8580, Japan
¹⁰ National Institute of Advanced Industrial Science and Technology, Koto, Tokyo 135-0064, Japan
¹¹ National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8567, Japan
¹² Planetary Exploration Research Center, Chiba Institute of Technology, Narashino, Chiba 275-0016, Japan
¹³ Institute of Planetary Research, German Aerospace Center (DLR), 12489 Berlin, Germany
¹⁴ Graduate University for Advanced Studies, SOKENDAI, Hayama, Kanagawa 240-0193, Japan
¹⁵ University of Tokyo, Kashiwa, Chiba 277-8561, Japan
¹⁶ Hiroshima University, 739-8526 Hiroshima, Japan
¹⁷ University of Potsdam, 14469 Potsdam, Germany
¹⁸ Institute of Space Systems, German Aerospace Center (DLR), 28359 Bremen, Germany
¹⁹ Institute of Geological Sciences, Free University of Berlin, 12249 Berlin, Germany

Received: 20 May 2022
Accepted: 30 August 2022

Abstract

Context. After landing on C-type asteroid Ryugu, MASCOT imaged brightly colored, submillimeter-sized inclusions in a small rock. Hayabusa2 successfully returned a sample of small particles from the surface of Ryugu, but none of these appear to harbor such inclusions. The samples are considered representative of Ryugu.

Aims. To understand the apparent discrepancy between MASCOT observations and Ryugu samples, we assess whether the MASCOT landing site, and the rock by implication, is perhaps atypical for Ryugu.

Methods. We analyzed observations of the MASCOT landing area acquired by three instruments on board Hayabusa2: a camera (ONC), a near-infrared spectrometer (NIRS3), and a thermal infrared imager. We compared the landing area properties thus retrieved with those of the average Ryugu surface.

Results. We selected several areas and landforms in the landing area for analysis: a small crater, a collection of smooth rocks, and the landing site itself. The crater is relatively blue and the rocks are relatively red. The spectral and thermophysical properties of the landing site are very close to those of the average Ryugu surface. The spectral properties of the MASCOT rock are probably close to average, but its thermal inertia may be somewhat higher.

Conclusions. The MASCOT rock can also be considered representative of Ryugu. Some of the submillimeter-sized particles in the returned samples stand out because of their atypical spectral properties. Such particles may be present as inclusions in the MASCOT rock.