Near-Infrared Observations of MUSES-C Mission Target
Near-Infrared Observations of MUSES-C Mission Target
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MUSES-C 任务目标的近红外观测
DOI：
10.1093/pasj/55.3.691
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发表时间：
2003
影响因子：
2.3
通讯作者：
S. Hasegawa
中科院分区：
文献类型：
--
作者：
M. Ishiguro;M. Abe;Y. Ohba;A. Fujiwara;T. Fuse;H. Terada;M. Goto;N. Kobayashi;A. Tokunaga;S. Hasegawa
我们给出了用8米斯巴鲁望远镜获得的日本小行星样品返回任务目标(25143)1998SF36的近红外光度和光谱观测结果。测得近红外色J−H=0.49±0.0 4，H−K=0.0 2±0.0 4，其中J、H、a ndk分别为中心波长1.2 5、1.6 3、2.12µm处的大小。将这些颜色与已知的分类类型小行星的颜色进行比较，我们发现这颗小行星是S类型的。我们将我们的M�波段(4.68um)光度数据与在中红外波长获得的N波段光度数据结合在一起。利用自由光束参数热模型(FBM)，推导出1998年SF36的几何尺寸为a=620±140m，b=280±60m，c=160±30m，V波段(0.55µm)几何反照率为0.35±0.11。从FBM得到的波束参数为1.1。结果表明，在S类小行星中，1998SF36的反照率较高，其热惯量似乎高于一般小行星的反照率。由此我们可以说，这颗小行星的表层厚度很薄，和/或表面覆盖着裸露的岩石。我们还获得了L波段(3.77微米)的光度和光谱数据。由于在3微米附近看不到明显的吸收带，我们估计表面材料的水丰度不到重量的1%。
We present near-infrared photometric and spectroscopic observations of the MUSES-C Japanese asteroid sample return mission target (25143) 1998 SF36, which were obtained with the 8-m SUBARU telescope. The near-infrared colors were found to be J − H =0.49 ±0.04 and H − K =0.02 ±0.04, where J, H ,a ndK are the magnitudes at the center wavelength of 1.25, 1.63, and 2.12 µm, respectively. Comparing these colors to those of known taxonomic type asteroids, we find this asteroid to be S-type. We combined our M � -band (4.68 µm) photometric data with N-band photometric data obtained at the mid-IR wavelength. Using the free beaming parameter thermal model (FBM), the derived size of 1998 SF36, assuming the shape of an ellipsoid, are a = 620 ±140m, b = 280 ±60m, and c = 160 ±30m, and geometric albedo in the V-band (0.55 µm) is 0.35 ±0.11. The beaming parameter from FBM is found to be 1.1. Our results show that the albedo of 1998 SF36 is high among S-type asteroids, and that the thermal inertia seems to be higher than that of average asteroids. From this we can say that the regolith thickness of this small asteroid is thin, and/or the surface is covered with bare rocks. We also obtained photometric and spectroscopic data in the L-band (3.77 µm). Since there is no clear absorption band seen around 3 µm, we estimate that the water abundance of the surface material is less than 1% in weight.