Meteor shower activity profiles and the use of orbital dissimilarity (D) criteria

TL;DR

This paper investigates how orbital dissimilarity criteria are used to identify meteor shower members, revealing that such methods may underestimate the true duration of showers due to orbital dispersion effects.

Contribution

It demonstrates the impact of orbital dissimilarity thresholds on meteor shower duration estimates and assesses measurement errors' influence on membership classification.

Findings

Orbital dissimilarity criteria can underestimate shower duration.

Dispersion in longitude affects shower membership identification.

Measurement errors influence the maximum allowed deviation.

Abstract

Orbital dissimilarity, or D, criteria are often used to select members of a meteor shower from a set of meteor observations. These criteria provide a quantitative description of the degree to which two orbits differ; if the degree of dissimilarity between a shower's reference orbit and an individual meteor does not exceed a selected threshold, the meteor is considered to be a member of that shower. However, members of a meteor shower tend to disperse in longitude of the ascending node (and thus in solar longitude) while preserving a common Sun-centered ecliptic radiant. Employing dissimilarity criteria to judge shower membership may therefore make the shower appear briefer than it actually is. We demonstrate this effect for two simulated meteor showers and assess the maximum permitted deviation in solar longitude as a function of radiant and velocity measurement error.