KPL/PCK Asteroid (162173) Ryugu PCK SPICE kernel File =========================================================================== This text PCK file contains the orientation and the size/shape data for Asteroid (162173) Ryugu. Version and Date -------------------------------------------------------- Version 1.0 -- December 10, 2021 -- Shin-ya Murakami, ISAS/JAXA Swap order of definition for Ryugu's NAIF name. Version 0.9 -- September 28, 2020 -- Shin-ya Murakami, Keio Univ. Versioning is changed to M.N fomat from YYYYMMDD that represents a release date of each shape model. This file is based on hyb2_ryugu_SHAPE_v20200323.tpc, file of Version 20200323. Applied cosmetic changes and improved descriptions. Added GM value from [5]. Version 20200323 -- March 23, 2020 -- Naru Hirata, The Univ. of Aizu Pole information estimated by Naoyuki Hirata (Kobe Univ.) with SPC. PM/W0 is adjusted to the official definition of the Hayabusa2 project. Values are not changed from the previous ones, but newly released to form the complete data set. Version 20190328 -- March 28, 2019 -- Naru Hirata, The Univ. of Aizu Pole information estimated by Naoyuki Hirata (Kobe Univ.) with SPC. PM/W0 is adjusted to the official definition of the Hayabusa2 project. Version 20190308 -- March 08, 2019 -- Naru Hirata, The Univ. of Aizu Pole information estimated by Naoyuki Hirata (Kobe Univ.) with SPC. PM/W0 is adjusted to the official definition of the Hayabusa2 project. Version 20181109 -- November 09, 2018 -- Naru Hirata, The Univ. of Aizu Pole information estimated by Naoyuki Hirata (Kobe Univ.) with SPC. PM/W0 is adjusted to the official definition of the Hayabusa2 project. Version 20181014 -- October 14, 2018 -- Naru Hirata, The Univ. of Aizu Pole information estimated by Naoyuki Hirata (Kobe Univ.) with SPC. PM/W0 is adjusted to the official definition of the Hayabusa2 project. Version 20180805 -- August 10, 2018 -- Naru Hirata, The Univ. of Aizu Pole information estimated by Naoyuki Hirata (Kobe Univ.) with SPC. PM/W0 is adjusted to the official definition of the Hayabusa2 project. Version 20180805 -- August 05, 2018 -- Naru Hirata, The Univ. of Aizu Pole information estimated by Naoyuki Hirata (Kobe Univ.) with SPC. PM/W0 is adjusted to the official definition of the Hayabusa2 project. Version 20180731 -- July 31, 2018 -- Naru Hirata, The Univ. of Aizu Pole information estimated by Naoyuki Hirata (Kobe Univ.) with SPC. PM/W0 is adjusted to the official definition of the Hayabusa2 project. Version 20180727 -- July 27, 2018 -- Naru Hirata, The Univ. of Aizu Pole information estimated by Naoyuki Hirata (Kobe Univ.) with SPC. PM/W0 is adjusted to the official definition of the Hayabusa2 project. Version 20180717 -- July 17, 2018 -- Naru Hirata, The Univ. of Aizu Pole information estimated by Naoyuki Hirata (Kobe Univ.) with SPC. PM/W0 is adjusted to the official definition of the Hayabusa2 project. Version 20180710 -- July 10, 2018 -- Naru Hirata, The Univ. of Aizu Pole information estimated by Naoyuki Hirata (Kobe Univ.) with SPC. PM/W0 is adjusted to the official definition of the Hayabusa2 project. Version 20180705 -- July 05, 2018 -- Naru Hirata, The Univ. of Aizu Pole information estimated by Naoyuki Hirata (Kobe Univ.) with SPC. PM/W0 is adjusted to the official definition of the Hayabusa2 project. Version 20180630 -- June 30, 2018 -- Naru Hirata, The Univ. of Aizu Pole information estimated by Naoyuki Hirata (Kobe Univ.) with SPC. PM/W0 is arbitrary adjusted to ONC images. Version 20180627 -- June 27, 2018 -- Naru Hirata, The Univ. of Aizu Pole information estimated by Naoyuki Hirata (Kobe Univ.) with SPC. PM/W0 is arbitrary adjusted to ONC images. Version 0.5 -- May 24, 2018 -- Yukio Yamamoto, ISAS/JAXA Fix asteroid parameters according to Mueller et al. (2017) Version 0.4 -- April 5, 2018 -- Yoshiaki Ishihara and Yukio Yamamoto, ISAS/JAXA Update asteroid parameters according to Mueller et al. (2017) Version 0.3 -- March 29, 2018 -- Shin-ya Murakami, ISAS/JAXA Update with some cosmetic changes. Version 0.2 -- May 18, 2017 -- Yoshiaki Ishihara and Yukio Yamamoto, ISAS/JAXA Split the FK and PCK contents into two kernels respectively. Version 0.1 -- June 16, 2016 -- Manabu YAMADA, PERC/Chitech Added the Ryugu name-ID mapping. Version 0.0 -- June 16, 2016 -- Yoshiaki Ishihara and Yukio Yamamoto, ISAS/JAXA Draft version by ground observation (As of Sep. 22, 2014). References -------------------------------------------------------- [1] Ishiguro, et al (2014), Optical Properties of (162173) 1999 JU3: In Preparation for the JAXA Hayabusa 2 Sample Return Mission, ApJ, 792, 74. https://doi.org/10.1088/0004-637X/792/1/74 [2] Mueller, et al (2017), Hayabusa-2 mission target asteroid 162173 Ryugu (1999 JU3): Searching for the object's spin-axis orientation, A&A, 599, A103. https://doi.org/10.1051/0004-6361/201629134 [3] Hirata (2020), Ryugu Coordinate System Description, in document collection of Hayabusa2 mission bundle. urn:jaxa:darts:hyb2:document:ryugu_coord_desc [4] Sugita, et al (2019), The geomorphology, color, and thermal properties of Ryugu: Implications for parent-body processes, Science, 364, 6437, eaaw0422. https://doi.org/10.1126/science.aaw0422 [5] Yamamoto, et al (2020), Dynamic precise orbit determination of Hayabusa2 using laser altimeter (LIDAR) and image tracking data sets, Earth, Planets and Space, 72, 85. https://doi.org/10.1186/s40623-020-01213-2 Contact Information -------------------------------------------------------- Naru Hirata, The University of Aizu, naru@u-aizu.ac.jp Parameter History -------------------------------------------------------- Date RA [deg] Dec. [deg] Period [h] Init.Rot.Angle(JD0) ---------- ----------- ---------- ---------- ------------------------- 2020-03-23 96.43112 -66.38741 7.632624787382541 2019-03-28 96.43112 -66.38741 7.632624787382541 2019-03-08 96.42997 -66.39277 7.6326238293793 2018-11-09 96.40503 -66.38442 7.632616576126643 2018-10-14 96.40101 -66.39948 7.632621866444357 2018-08-29 96.39792 -66.39867 7.632622910551389 2018-08-10 96.39069 -66.40321 7.632625803575571 2018-08-05 96.38837 -66.40425 7.632626749577289 2018-07-31 96.37915 -66.41831 7.632613738534321 2018-07-27 96.35333 -66.42016 7.632595559221877 2018-07-17 96.36813 -66.40245 7.63255 2018-07-10 96.34221 -66.42105 7.63253 2018-07-05 96.33551 -66.47482 7.63249 2018-06-30 96.17157 -66.53653 7.63253 2018-06-27 95.783988 -66.382491 7.63109 in J2000EQ Date Lambda[deg] Beta[deg] Period [h] Init.Rot.Angle(JD0) ---------- ----------- ---------- ---------- ------------------------- 2018-04-05 310.0-340.0 -40.0+-15 7.63109 2016-03-04 329.0+-10 -39.0+-20 7.6312 phi0=0 JD0=2454289.000000 2014-09-22 325.0+-10 -40.0+-15 7.6312 2014-09-19 326.478506 -36.065302 7.63121164 phi0=0 JD0=2454289.000000 As of September 22, 2014 From private communication with Thomas Mueller: Rotational period 7.6312 +- 0.0010 hr H0 in V-band 19.25 +- 0.03 G parameter (a<30 deg) 0.3 +- 0.02 Geometric albedo 0.047 +- 0.003 Effective diameter 875 +- 15 m Thermal inertia 50 +- 50 J(m^2*s^0.5*K) Pole orientation (l, b) = (325, -40) +- (10, 15) deg l ... lambda_ecl (Ecliptic longitude) b ... beta_ecl (Ecliptic latitude) As of March 4, 2016, From design reference: Rotational period 7.6312 hr G parameter (a<30 deg) 0.13 +- 0.02 Geometric albedo 0.047 +- 0.043-0.050 (V-band) Effective diameter 880 +- 15 m Thermal inertia 250 +- 150-500 J/(m^2*s^0.5*K) Pole orientation (l, b) = (329, -39) +- (10, 20) deg Surface slope 0.1 rms GM 32 m^3/s^2 Ellipsoidal shape a=446.5, b=439.7, c=433.9 m Axis ratios (a/b, b/c) = (1.0153, 1.0135) As of March 9, 2017, Rotational period 7.63109 hr [2] H0 in V-band 19.22 +- 0.02 [1] G parameter (a<30 deg) 0.13 +- 0.02 [1] Geometric albedo 0.047 +- 0.003 [1] Effective diameter 850 - 880 m [2] Thermal inertia 150 - 300 J/(m^2*s^0.5*K) [2] Pole orientation (l, b) = (340, -40) deg (Table 5, ID 2) [2] Heat conductivity 0.1 to 0.6 W/(K*m) [2] Grain size 1 - 10 mm [2] Axis ratios (a/b, b/c) = (1.025, 1.014) [2] Values in Version 20181109 body2162173_pole_ra = ( 96.40503 0.0 0.0 ) body2162173_pole_dec = ( -66.38442 0.0 0.0 ) body2162173_pm = ( 265.94597 1131.98402066 0.0 ) Values in Version 1.0 The W0 term for the prime meridian (PM) is set to 274.16225. The W1 term is set to 1131.98280286 that corresponds to the period of 7.632624787 hours. 360 [deg/rev] x 24 [hours/day] / ( 1131.98280286 [deg/day] ) = 7.63262478738254 [hours/rev] \begindata BODY2162173_POLE_RA = ( 96.43112 0.0 0.0 ) BODY2162173_POLE_DEC = ( -66.38741 0.0 0.0 ) BODY2162173_PM = ( 274.16225 1131.98280286 0.0 ) \begintext Radii for asteroid (162173) Ryugu -------------------------------------------------------- The radii provided in the keyword below are also from [3]. \begindata BODY2162173_RADII = ( 0.502 0.502 0.438 ) \begintext Albedo values for asteroid (162173) Ryugu -------------------------------------------------------- The albedo provided in the keywords below is taken from [4]. \begindata BODY2162173_ALBEDO_GEOMETRIC = 0.045 \begintext GM value for asteroid (162173) Ryugu -------------------------------------------------------- The GM value provided in the keywords below is GM = 29.8 +- 0.3 m^3/s^2, taken from [5]. UNITS: km^3/s^2 \begindata BODY2162173_GM = 2.98E-08 \begintext Asteroid (162173) Ryugu name-ID mappings -------------------------------------------------------- The keywords below implement the Ryugu name-ID mappings. \begindata NAIF_BODY_NAME += ( '1999JU3' ) NAIF_BODY_CODE += ( 2162173 ) NAIF_BODY_NAME += ( 'RYUGU' ) NAIF_BODY_CODE += ( 2162173 ) \begintext End of PCK file.