RADIATION PRESSURE ON FLUFFY SUBMICRON-SIZED GRAINS
RADIATION PRESSURE ON FLUFFY SUBMICRON-SIZED GRAINS
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DOI：
10.3847/0004-637x/818/2/133
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发表时间：
2015-08
期刊：
影响因子：
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通讯作者：
Kedron Silsbee;B. Draine
中科院分区：
文献类型：
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作者：
Kedron Silsbee;B. Draine
我们研究了太阳系中尘埃颗粒上的辐射压力与引力之比β对于某些颗粒尺寸可以大大超过1的说法，只要颗粒孔隙度足够高。对于由硅酸盐小球的随机聚集体组成的模型颗粒，我们发现β的最大值几乎与颗粒的孔隙度无关，但对于小颗粒（），β实际上随孔隙度的增加而减小。我们还研究了尘埃颗粒中金属铁和无定形碳夹杂物的影响，发现虽然这些夹杂物确实增加了辐射压力截面，但对于含有3 pg硅酸盐材料的颗粒，β仍然低于1。这些结果影响了对星尘号使命估计的颗粒轨迹的解释，这些颗粒轨迹是在假设β值超过1的情况下建模的。我们发现，辐射压力的影响是不够大的粒子猎户座和Hylabrook捕获的星尘是星际起源的报告的影响速度。我们还考虑了太阳辐射对横向速度和颗粒自旋的影响，并表明辐射压力引入了横向速度和赤道自旋速度为每秒几百米的传入星际颗粒在2 Au。这些横向速度对于轨迹建模并不重要，但是这样的旋转速率可能导致聚集体的离心破裂。
We investigate the claim that the ratio β of radiation pressure force to gravitational force on a dust grain in our solar system can substantially exceed unity for some grain sizes, provided that grain porosity is high enough. For model grains consisting of random aggregates of silicate spherules, we find that the maximum value of β is almost independent of grain porosity, but for small ( ) grains, β actually decreases with increasing porosity. We also investigate the effect of metallic iron and amorphous carbon inclusions in the dust grains and find that while these inclusions do increase the radiation pressure cross-section, β remains below unity for grains with 3 pg of silicate material. These results affect the interpretation of the grain trajectories estimated from the Stardust mission, which were modeled assuming β values exceeding one. We find that radiation pressure effects are not large enough for particles Orion and Hylabrook captured by Stardust to be of interstellar origin given their reported impact velocities. We also consider the effects of solar radiation on transverse velocities and grain spin, and show that radiation pressure introduces both transverse velocities and equatorial spin velocities of several hundred meters per second for incoming interstellar grains at 2 au. These transverse velocities are not important for modeling trajectories, but such spin rates may result in centrifugal disruption of aggregates.