论文标题
来自南半球的近地小行星（163899）2003 SD220的近地雷达观测
Bistatic Radar Observations of Near-Earth Asteroid (163899) 2003 SD220 from the Southern Hemisphere
论文作者
论文摘要
我们报告了堪培拉-ATCA多普勒连续波（CW）近地小行星（163899）2003 SD220的雷达观测值，其接收频率为7159 MHz（4.19厘米）（4.19厘米），2018年12月20日，21日，在0.019 au（7.4 lunar lunar distantes）内的紧密接近近距离接近。回声功率光谱提供了证据表明该形状显着伸长，不对称，并且至少具有一个相对较大的凹度。每个轨道的平均光谱得出0.39、0.27和0.25 km $^{2} $的OC（相反的圆极化）横截面，不确定性为35 \％。在三天内，在肢体到末端带宽中大约有两个因子的变化表明伸长对象的旋转。我们获得的圆极化比为0.21 $ \ pm $ 0.07，这与雷达观察到的其他S级接近地球小行星相一致，但略低于其他S级接近地球小行星。
We report results of Canberra-ATCA Doppler-only continuous wave (CW) radar observations of near-Earth asteroid (163899) 2003 SD220 at a receiving frequency of 7159 MHz (4.19 cm) on 2018 December 20, 21, and 22 during its close approach within 0.019 au (7.4 lunar distances). Echo power spectra provide evidence that the shape is significantly elongated, asymmetric, and has at least one relatively large concavity. An average spectrum per track yields an OC (opposite sense of circular polarisation) radar cross section of 0.39, 0.27, and 0.25 km$^{2}$, respectively, with an uncertainty of 35 \%. Variations by roughly a factor of two in the limb-to-limb bandwidth over the three days indicate rotation of an elongated object. We obtain a circular polarization ratio of 0.21 $\pm$ 0.07 that is consistent with, but somewhat lower than, the average among other S-class near-Earth asteroids observed by radar.
