The Dust Grains from 9P/Tempel 1 Before and After the Encounter with Deep Impact
The Dust Grains from 9P/Tempel 1 Before and After the Encounter with Deep Impact
复制标题
9P/Tempel 1 遭遇深度撞击前后的尘粒
作者：
D. Harker;C. Woodward;D. Wooden
双子座N观测了9P/坦普尔1号彗星在遭遇深度撞击前后的尘埃特性。在7.8到13微米的光谱能量分布和派生的内部彗发的颗粒性质中看到了显著的变化。撞击后1小时，由无定形辉石、无定形橄榄石和富镁结晶橄榄石的排放物主导的强烈、宽广的硅酸盐特征已经形成。根据我们的模型，抛出的尘埃质量为≅104至106千克。26小时后，硅酸盐特征已经褪色，留下了一个平滑而无特征的光谱，与撞击前观察到的光谱相似，这表明撞击没有产生一个新的活动区，在原子核上释放小粒子。
Gemini-N observed the properties of dust ejected from the nucleus of comet 9P/Tempel 1 before and after its encounter with Deep Impact. Marked changes were seen in the 7.8- to 13-micrometer spectral energy distribution and derived grain properties of the inner coma. A strong, broad silicate feature dominated by emission from amorphous pyroxene, amorphous olivine, and magnesium-rich crystalline olivine had developed by 1 hour after impact. The ejected dust mass is ≅104 to 106 kilograms on the basis of our models. Twenty-six hours later the silicate feature had faded, leaving a smooth featureless spectrum, similar to that observed before the impact, suggesting that the impact did not produce a new active region releasing small particles on the nucleus.