Modeling the past and future activity of the Halleyid meteor showers

Abstract

Context. We present a new numerical model of the η-Aquariid and Orionid meteor showers. Aims. The model investigates the origin, variability, and age of the η-Aquariid and Orionid apparitions from 1985 to the present day in order to forecast their activity over the next several decades. Methods. Through the numerical integration of millions of simulated meteoroids and a custom-made particle weighting scheme, we model the characteristics of every η-Aquariid and Orionid apparition between 1985 and 2050. The modeled showers are calibrated using 35 yr of meteor observations, including the shower activity profiles and interannual variability. Results. Our model reproduces the general characteristics of the present-day η-Aquariids and part of the Orionid activity. Simulations suggest that the age of the η-Aquariids somewhat exceeds 5000 yr, while a greater fraction of the Orionids is composed of older material. The 1:6 mean motion resonance with Jupiter plays a major role in generating some (but not all) Halleyid stream outbursts. We find consistent evidence for a periodicity of 11.8 yr in both the observations and modeled maximum meteor rates for the Orionids. Weaker evidence of a 10.7 yr period in the peak activity for the η-Aquariids needs to be investigated with future meteor observations. The extension of our model to future years predicts no significant Orionid outbursts through 2050 and four significant η-Aquariid outbursts, in 2023, 2024, 2045, and 2046.

Meteor shower radiant dispersions in Global Meteor Network data

“…This opens up the possibility that some of these meteoroid streams may be elliptical in cross-section. This is supported by other studies: for instance, both observations (Vida 2020) and models (Egal et al 2020) of the Orionid meteor shower indicate a complex radiant structure. An apparently asymmetric Orionid radiant distribution is also presented in Fig.…”

The Global Meteor Network -- Methodology and First Results

“…In that study, the GMN contributed the most observed trajectories and the GMN mean orbit was in agreement with orbits reported by other networks. Finally, Egal et al (2020) performed dynamical simulations of the Orionids and the 𝜂-Aquariids, and shown that the radiants observed by the GMN were a good match to their simulations.…”

“…Characterization of the absolute flux, variability and particle ★ E-mail: dvida@uwo.ca distribution within streams can therefore provide unique insights into parent body physical properties and evolution (e.g. Egal et al 2020).…”

Computing optical meteor flux using Global Meteor Network data

“…Another potential source of error might be the power law assumption. For example, using a numerical model of meteoroid ejection from comet 1P/Halley, Egal et al (2020) predicted that Orionid meteoroids arriving at the Earth should have a mass distribution which follows a broken power law, notably with several sharp slope changes around 1 mm sizes.…”