论文标题
Comet C/2018 V1的极低线性极化（Machholz-Fujikawa-Iwamoto）
Extremely low linear polarization of comet C/2018 V1 (Machholz-Fujikawa-Iwamoto)
论文作者
论文摘要
我们在2018年11月中旬测量了Comet C/2018 V1（Machholz-Fujikawa-Iwamoto）的线性极化P度（Machholz-Fujikawa-Iwamoto）。在2018年11月中旬。在\ r {ho r {ho} = 17,000 km的半径范围内，我们在83至91至91 and Cheper and copare coma的coma coma coma coma = 17,000 km，并且在83至91.2 teply and clase ofer ancy plassection = 83至91.2。 +/- 1.8）％。这是彗星中有史以来最低的PMAX。使用模型团聚的碎屑颗粒，我们重现了彗星C/2018 V1的极化响应。四个检索折射率与富含铁含量或没有铁含量的富含MG的硅酸盐中发现的折射率非常匹配。此外，聚集的碎屑颗粒的尺寸分布与彗星1p/halley的原位发现符合良好的定量一致。彗星C/2018 V1极化的尘埃模型表明，振幅| PMIN | = 5％-7％；而基于气态发射的解释需要在小相角下无负极化。这种戏剧性的差异可以用来区分低pmax彗星中的气体发射和灰尘解释。
We measured the degree of linear polarization P of comet C/2018 V1 (Machholz-Fujikawa-Iwamoto) with the broadband Johnson V filter in mid-November of 2018. Within a radius of \r{ho}=17,000 km of the inner coma, we detected an extremely low linear polarization at phase angles from 83 to 91.2 degree and constrained the polarization maximum to Pmax = (6.8 +/- 1.8)%. This is the lowest Pmax ever measured in a comet. Using model agglomerated debris particles, we reproduced the polarimetric response of comet C/2018 V1. Four retrieved refractive indices closely match what was experimentally found in Mg-rich silicates with little or no iron content. Moreover, the size distribution of the agglomerated debris particles appears in good quantitative agreement with the in situ findings of comet 1P/Halley. The dust model of polarization of comet C/2018 V1 suggests a strongly negative polarization with amplitude |Pmin| = 5%-7%; whereas, an interpretation based on gaseous emission requires no negative polarization at small phase angles. This dramatic difference could be used to discriminate gaseous-emission and dust explanations in low-Pmax comets in future.
