Meteor shower radiant dispersions in Global Meteor Network data

TL;DR

This study measures and analyzes the dispersion of meteor shower radiants using Global Meteor Network data, revealing variations among showers and their implications for understanding meteoroid streams and Earth's gravitational effects.

Contribution

It provides new measurements of radiant dispersion for twelve meteor showers and examines their relationship with shower duration and other parameters.

Findings

Median radiant offset ranges from 0.32° to 1.41°

Detected a small but significant drift in radiant and speed over time

Radiant dispersion is not correlated with shower duration

Abstract

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 twelve 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$^\circ$ for the eta Aquariids to 1.41$^\circ$ for the Southern Taurids. We also find that there is a small but statistically significant drift in Sun-centered 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.