Derivation of 1.064 μm normal albedos on the C-type asteroid Ryugu from laser pulse intensity measurement of the Hayabusa2 LIDAR

Autor: Ryuhei Yamada, Keiko Yamamoto, Shoko Oshigami, Hiroshi Araki, Hiroki Senshu, Hirotomo Noda, Noriyuki Namiki, Koji Matsumoto, Fumi Yoshida, Shinsuke Abe, Naru Hirata, Sho Sasaki, Takahide Mizuno
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Earth, Planets and Space, Vol 74, Iss 1, Pp 1-18 (2022)
Druh dokumentu: article
ISSN: 1880-5981
DOI: 10.1186/s40623-022-01717-z
Popis: Abstract Japanese asteroid explorer Hayabusa2 arrived at C-type asteroid 162,173 Ryugu in June 2018. The laser altimeter (LIDAR) onboard Hayabusa2 measured its own transmitted laser and returned pulse intensities from a Ryugu surface until November 2019. Because the Ryugu surface is extremely rough, topography dominates over the material properties in the conventional derivation of normal albedo. Thus, we developed a method to retrieve the normal albedo from the rough surface of a C-type asteroid at a LIDAR laser wavelength of 1.064 μm. The albedo map covering an equatorial band between – 40° and + 20° in latitude was created with 3˚-by-3˚ resolution using the intensity data obtained before the conjunction of the spacecraft with the Sun. The average of the normal albedo is 0.0405 $$\pm$$ ± 0.0027, whereas approximately half of the 3°-by-3° grids are between 0.04 and 0.045. The low and uniform normal albedo feature is common to other remote-sensing observations of Ryugu by visible and near-infrared cameras onboard Hayabusa2. Graphical Abstract
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