Tau Herculids 2022: Rate, number density, population index and geometrical effects from visual data

TL;DR

This study analyzes visual data of the Tau Herculids meteor shower in 2022, estimating its population index, rate, density, and effects of geometrical factors, providing detailed observational insights into its activity and origins.

Contribution

It presents the first detailed analysis of visual observations of the 2022 Tau Herculids, including population index, activity maxima, and geometrical effects, enhancing understanding of this meteor shower.

Findings

Population index for the entire sample is 2.4.

Maximum ZHR of 55±7 on May 31, 2022.

Estimated spatial number density of approx. 380 meteoroids larger than 10mg.

Abstract

We analysed visual observation data of the Tau Herculids collected between 2022 May 28 and June 1. The population index for the entire sample is 2.4. For the pre-peak period we find r=2.57+-0.23, the peak period yields r=2.38+-0.06. The ZHR maximum of the 1995 ejecta from comet Schwassmann-Wachmann3 (SW3) is found at 69.450 deg solar longitude (May 31, 05h04mUT, +-5min) with a ZHR=55+-7, corresponding to a spatial number density ND of approx. 380 meteoroids larger than 10mg in a cube with 1000km edge length. An earlier maximum occurred at 69.207 deg solar longitude (centred May 30, 23h UT) with a ZHR=18+-3 and is tentatively associated with SW3-ejecta from 1892. Effects of the radiant shift due to the large zenith attraction of about 10 deg for the radiant close to the horizon are discussed.