Meteor showers occur when streams of meteoroids originating from a common source intersect the Earth. There will be small dissimilarities between the direction of motion of different meteoroids within a stream, and these small differences will act to broaden the radiant, or apparent point of origin, of the shower. This dispersion in meteor radiant can be particularly important when considering the effect of the Earth’s gravity on the stream, as it limits the degree of enhancement of the stream’s flux due to gravitational focusing. In this paper, we present measurements of the radiant dispersion of 12 showers using observations from the Global Meteor Network. We find that the median offset of individual meteors from the shower radiant ranges from 0.32○ for the eta Aquariids to 1.41○ for the Southern Taurids. We also find that there is a small but statistically significant drift in Sun-centred ecliptic radiant and/or geocentric speed over time for most showers. Finally, we compare radiant dispersion with shower duration and find that, in contrast with previous results, the two quantities are not correlated in our data.

中文翻译：

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全球流星网络数据中的流星雨辐射分散

当来自一个共同来源的流星体流与地球相交时，就会发生流星雨。流中不同流星体的运动方向会有微小的差异，这些微小的差异将扩大流星雨的辐射范围或明显的起源点。在考虑地球重力对流的影响时，流星辐射的这种分散可能特别重要，因为它限制了由于重力聚焦而增强的流通量的程度。在本文中，我们使用来自全球流星网络的观测结果展示了 12 场流星雨的辐射散射测量结果。我们发现个别流星与淋浴辐射的中值偏移范围从宝瓶座 eta 的 0.32○ 到金牛座南部的 1.41○。我们还发现，随着时间的推移，大多数流星雨的以太阳为中心的黄道辐射和/或地心速度存在微小但具有统计学意义的漂移。最后，我们将辐射色散与阵雨持续时间进行比较，发现与之前的结果相比，这两个量在我们的数据中不相关。