This page provides (162173) Ryugu maps, including background (texture) maps and derived color maps used in the Hayabusa2 data search and visualization system (JADE2).
JADE2: https://jade2.darts.isas.jaxa.jp

Please see here for background maps previously used in JADE.

About the Data

The data on this page are provided mainly in the following formats:

GeoTIFF format: Data with geographic information. These files can be used directly in GIS software such as QGIS. (Original values)

JPEG format: Image data for quick viewing and reference. (Values are scaled for 8 bit)

For analysis and further use, the GeoTIFF format is recommended.

All datasets are provided using the equirectangular projection (simple cylindrical projection), which represents the surface of Ryugu on a two-dimensional plane based on latitude and longitude coordinates. This projection is convenient for global surface analysis, although it may introduce distortions in area and distance at high latitudes.

1. High-Resolution Mosaic Maps

Three types of high-resolution mosaic maps based on the telescopic Optical Navigation Camera (ONC-T) are available in JADE2.

Global map 1

Created from images acquired between June 30, 2018 and November 22, 2018 (prior to the conjunction operation).

A global mosaic created mainly from images acquired at an altitude of 20 km, supplemented with images acquired at 5 km altitude during the middle-altitude operations.

Resolution: 0.1 deg/pixel (approximately 0.88 m/pixel at the equator).

Global map 2

Created from images acquired between January 21, 2019 and November 7, 2019 (after the conjunction operation).

A global mosaic created mainly from images acquired at an altitude of 20 km, supplemented with images acquired at 5 km altitude during the BOX-C operations.

Resolution: 0.1 deg/pixel (approximately 0.88 m/pixel at the equator).

High resolution

Created from images acquired on October 3–4, 2018 during the MASCOT separation operation.

A mosaic created from images acquired at an altitude of 3 km, covering low-latitude regions only (within ±30° latitude).

Resolution: 0.036 deg/pixel (approximately 0.28 m/pixel at the equator).

2. False-Color Map (Normal Albedo RGB Map)

　

This map represents the surface color of Ryugu using a false-color RGB composite based on Normal Albedo data observed by ONC-T.

Observations conducted with the Sun positioned behind the spacecraft produce images with minimal shadows, similar to the appearance of a full Moon. The reflectance measured under these conditions is referred to as normal albedo. Because such images are minimally affected by surface topography, they are well suited for analyzing surface color variations (Yokota et al. 2021).

Separate observation bands are assigned to each RGB color channel. Since these wavelengths differ from those perceptible to the human eye, the resulting image is presented as a false-color composite.

Blue channel: 480 nm (b-band)
Green channel: 549 nm (v-band)
Red channel: 857 nm (x-band)

Although Ryugu would appear nearly black and colorless to the human eye, subtle spectral differences are enhanced in this map to facilitate visual discrimination.

3. Albedo Map (v-band Normal Albedo Map)

This map is derived from the same normal albedo dataset described in Section "2. False-Color Map (Normal Albedo RGB Map)" and shows the albedo at 550 nm (Yokota et al. 2021).

This wavelength corresponds to the astronomical v-band, which is commonly used for brightness comparisons.

4. Spectral Slope Map (b–x Slope Map)

Although Ryugu shows relatively weak intrinsic color variation, several studies have reported regional variations in spectral slope within the visible to near-infrared wavelength range (approximately 0.55–0.86 µm).

This map calculates spectral slope values using the normal albedo data described in Section 2 and reproduces the distribution reported in Kameda et al. 2021.

5．Thermal Inertia Map

The thermal inertia map shows how rapidly the surface of Ryugu responds to temperature changes. Regions with low thermal inertia tend to heat up and cool down quickly.

This map is derived from Hayabusa2 Thermal Infrared Imager (TIR) data by applying a physical thermal model to observed diurnal temperature variations (Shimaki et al. 2020).

Variations in thermal inertia are related to surface properties such as rock abundance and the presence of fine-grained material, providing insights into the physical environment around craters, boulders, and landing sites.

Black regions indicate areas where no valid data are available.

Reference:

• Sugita et al. (2019). The geomorphology, color, and thermal properties of Ryugu: Implications for parent-body processes, Science 364, 6437. https://doi.org/10.1126/science.aaw0422
• Yokota et al. (2021). Opposition Observations of 162173 Ryugu: Normal Albedo Map Highlights Variations in Regolith Characteristics, Planet. Sci. J. 2 177. https://doi.org/10.3847/PSJ/ac14ba
• Kameda et al. (2021). Improved method of hydrous mineral detection by latitudinal distribution of 0.7-μm surface reflectance absorption on the asteroid Ryugu, Icarus 360, 114348. https://doi.org/10.1016/j.icarus.2021.114348
• Shimaki et al. (2020). Thermophysical properties of the surface of asteroid 162173 Ryugu: Infrared observations and thermal inertia mapping, Icarus 348, 113835. https://doi.org/10.1016/j.icarus.2020.113835