Optical Properties of (162173) 1999 JU3: In Preparation for the JAXA Hayabusa 2 Sample Return Mission

Masateru Ishiguro, Daisuke Kuroda, Sunao Hasegawa, Myung-Jin Kim, Young-Jun Choi, Nicholas Moskovitz, Shinsuke Abe, Kang-Sian Pan, Jun Takahashi, Yuhei Takagi, Akira Arai, Noritaka Tokimasa, Henry H. Hsieh, Joanna E. Thomas-Osip, David J. Osip, Masanao Abe, Makoto Yoshikawa, Seitaro Urakawa, Hidekazu Hanayama, Tomohiko SekiguchiKohei Wada, Takahiro Sumi, Paul J. Tristram, Kei Furusawa, Fumio Abe, Akihiko Fukui, Takahiro Nagayama, Dhanraj S. Warjurkar, Arne Rau, Jochen Greiner, Patricia Schady, Fabian Knust, Fumihiko Usui, Thomas G. Müller

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38 Citations (SciVal)


We investigated the magnitude-phase relation of (162173) 1999 JU3, a target asteroid for the JAXA Hayabusa 2 sample return mission. We initially employed the International Astronomical Union's H-G formalism but found that it fits less well using a single set of parameters. To improve the inadequate fit, we employed two photometric functions: the Shevchenko and Hapke functions. With the Shevchenko function, we found that the magnitude-phase relation exhibits linear behavior in a wide phase angle range (α = 5°-75°) and shows weak nonlinear opposition brightening at α < 5°, providing a more reliable absolute magnitude of H V = 19.25 ± 0.03. The phase slope (0.039 ± 0.001 mag deg–1) and opposition effect amplitude (parameterized by the ratio of intensity at α = 03 to that at α = 5°, I(03)/I(5°) = 1.31 ± 0.05) are consistent with those of typical C-type asteroids. We also attempted to determine the parameters for the Hapke model, which are applicable for constructing the surface reflectance map with the Hayabusa 2 onboard cameras. Although we could not constrain the full set of Hapke parameters, we obtained possible values, w = 0.041, g = –0.38, B 0 = 1.43, and h = 0.050, assuming a surface roughness parameter = 20°. By combining our photometric study with a thermal model of the asteroid, we obtained a geometric albedo of p v = 0.047 ± 0.003, phase integral q = 0.32 ± 0.03, and Bond albedo A B = 0.014 ± 0.002, which are commensurate with the values for common C-type asteroids.
Original languageEnglish
Pages (from-to)74
Number of pages1
JournalAstrophysical Journal
Issue number1
Publication statusPublished - 18 Aug 2014


  • meteorites
  • meteors
  • meteoroids
  • minor planets
  • asteroids
  • Astrophysics
  • Earth and Planetary Astrophysics


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