OPTICAL PROPERTIES OF (162173) 1999 JU3: IN PREPARATION FOR THE JAXA HAYABUSA 2 SAMPLE RETURN MISSION
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 inadeq...
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Veröffentlicht in: | The Astrophysical journal 2014-09, Vol.792 (1), p.1-9 |
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Zusammenfassung: | 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 ( alpha = 5[degrees]-75[degrees]) and shows weak nonlinear opposition brightening at alpha < 5[degrees], providing a more reliable absolute magnitude of Hv = 19.25 + or - 0.03. The phase slope (0.039 + or - 0.001 mag deg super(-1)) and opposition effect amplitude (parameterized by the ratio of intensity at alpha = 0[degrees].3 to that at alpha = 5[degrees], I(0.[degrees]3)/I(5[degrees]) = 1.31 + or - 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 sub(0) = 1.43, and h = 0.050, assuming a surface roughness parameter [theta] = 20[degrees]. By combining our photometric study with a thermal model of the asteroid, we obtained a geometric albedo of p sub(v) = 0.047 + or - 0.003, phase integral q = 0.32 + or - 0.03, and Bond albedo A sub(B) = 0.014 + or - 0.002, which are commensurate with the values for common C-type asteroids. |
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ISSN: | 1538-4357 0004-637X 1538-4357 |
DOI: | 10.1088/0004-637X/792/1/74 |