论文标题
卫星观察2018年12月18日在白令海举行的重大bolide赛事的尘埃径
Satellite observation of the dust trail of a major bolide event over the Bering Sea on December 18, 2018
论文作者
论文摘要
近几十年来，美国政府传感器（USGS）在2018年12月18日在白令海的偏远地区发现了最有活力的炸弹事件之一。不存在基于地面的光学观察。我们使用钢铁岛留下的尘埃径的卫星图像，我们试图重建钢铁轨迹。结合USGS报告的炸药速度，我们计算了大气前轨道。从0.4到13.3微米的各种光谱带的观测使我们能够研究灰尘特性。使用了Terra卫星和地球静止卫星Himawari-8和Goes-17从各个角度获得的尘埃径及其阴影的图像。步道的初始位置和方向变化，并计算出其在Geoid坐标网格中的投影，并将其与真实数据进行比较。考虑到大气风引起的步道运动。尘埃径的选定部分的辐射和反射是从MODIS仪器中取出的。将反射光谱与小行星光谱进行了比较。在Azimuth 130 \ degr \（从南到西）和Zenith距离14 \ degr的Azimuth 130 \ degr上发现，抗Bolide辐射量比USGS报道的乙酰辐射为13 +/- 9度。确认了硼化物位置，包括大约25公里的最大灰尘沉积高度。进入的小行星必须非常强大才能将高速降至这一高度。 USGS报告的32 km/s的速度被认为是合理的。该轨道的倾斜度高约50 \ degr \，而近日距离为0.95-1 au。半轴轴不能很好地限制，但很可能在1-3 au之间。蓝色的尘埃反射率要比红色低得多，与A-或L型小行星的材料一致。 11微米处的吸收证实了灰尘中的结晶硅酸盐的存在。
One of the most energetic bolide events in recent decades was detected by the US Government sensors (USGS) over remote areas of the Bering Sea on December 18, 2018, 23:48 UT. No ground-based optical observations exist. Using the satellite imagery of the dust trail left behind by the bolide, we tried to reconstruct the bolide trajectory. In combination with the bolide speed reported by the USGS, we computed the pre-atmospheric orbit. Observations in various spectral bands from 0.4 to 13.3 microns enabled us to study the dust properties. Images of the dust trail and its shadow obtained from various angles by the MISR instrument on board the Terra satellite and geostationary satellites Himawari-8 and GOES-17 were used. The initial position and orientation of the trail was varied, and its projections into the geoid coordinate grid were computed and compared with real data. Trail motion due to atmospheric wind was taken into account. Radiances and reflectances of selected parts of the dust trail were taken from the MODIS instrument. Reflectance spectra were compared with asteroid spectra. The bolide radiant was found to be 13 +/- 9 degrees from that reported by the USGS, at azimuth 130\degr\ (from south to west) and zenith distance 14\degr. The bolide position was confirmed, including the height of maximum dust deposition around 25 km. The incoming asteroid had to be quite strong to maintain a high speed down to this height. The speed of 32 km/s, reported by the USGS, was found to be plausible. The orbit had a high inclination of about 50\degr\ and a perihelion distance between 0.95-1 AU. The semimajor axis could not be restricted well but was most probably between 1-3 AU. The dust reflectance was much lower in the blue than in the red, consistent with the material of A- or L-type asteroid. The absorption at 11 microns confirms the presence of crystalline silicates in the dust.
