A dynamical analysis of the Taurid Complex: evidence for past orbital convergences

Abstract

The goal of this work is to determine if the dynamics of individual Taurid Complex (TC) objects are consistent with the formation of the complex via fragmentation of a larger body, or if the current orbital affinities between the TC members result from other dynamical processes. To this end, the orbital similarity through time of comet 2P/Encke, fifty-one Near-Earth Asteroids (NEAs) and sixteen Taurid fireballs was explored. Clones of each body were numerically simulated backwards in time, and epochs when significant fractions of the clones of any two bodies approached each other with both a low Minimum Orbit Intersection Distance and small relative velocity were identified. Only twelve pairs of bodies in our sample show such an association in the past 20 000 years, primarily circa 3200 BCE. These include 2P/Encke and NEAs 2004 TG10, 2005 TF50, 2005 UR, 2015 TX24, and several Southern Taurid fireballs. We find this orbital convergence to be compatible with the fragmentation of a large parent body five to six thousand years ago, resulting in the separation of 2P/Encke and several NEAs associated with the TC, as well as some larger meteoroids now recorded in the Taurid stream. However, the influence of purely dynamical processes may offer an alternative explanation for this orbital rapprochement without requiring a common origin between these objects. In order to discriminate between these two hypotheses, future spectral surveys of the TC asteroids are required.

Data on 824 fireballs observed by the digital cameras of the European Fireball Network in 2017–2018

“…These asteroids can be considered as large members of the stream rather than parent bodies. Egal et al (2021) confirm their orbital convergence with 2P/Encke and also with 2004 TG10, which is now related to the Northern Taurids, about 5000 years ago. Here we note the close orbital similarity of another asteroid, 2014 NK52, with the Northern Taurids, namely with those observed around mid-November (while the orbit of 2004 TG10 is more similar to NTA meteors observed earlier in November).…”

An observational synthesis of the Taurid meteor complex

“…However, this apparent negative observation is less clear as only a large enhancement in fireball rates would be detectable for these daylight streams. Following the call for observations of Clark et al (2019), several new asteroids residing in the 7:2 MMR with Jupiter were discovered during the last return of the TSC in June 2019 (Egal et al 2021). Future swarm years are expected to occur in 2022, 2025 and 2032 for the autumn showers and 2026 and 2029 for the daytime Taurids.…”

“…The semi-major axis extent of the 7:2 MMR at an eccentricity of 0.85-0.87 ranges from about 2.23 to 2.28 AU (Asher 1991;Egal et al 2021). The distribution of the orbital elements of the NTA and STA largely spans the full extent of the resonance (see Figure C3.1), making it possible in principle to observe the TSC returns with different detection methods measuring particles at different sizes.…”

“…The existence of several branches in the Taurid stream has often been interpreted as a sign of old age. It takes about 5000 to 6000 years for 2P/Encke's orbit to cover one full cycle in perihelion argument (Egal et al 2021), depending on semi-major axis. Assuming 2P/Encke (or an object on a similar orbit) is the unique parent body of the four major Taurid showers, a time of at least one precession period is required to create a meteor shower at the ascending and descending node of the stream, with a northern and a southern branch.…”

“…Such associations support the original hypothesis of Clube & Napier (1984) that the Taurid stream was formed as a result of successive fragmentations of a large parent body a few thousand years ago. However, one must proceed with caution when searching for possible linkages among the different objects of the Taurid complex, given the multiple dynamical pathways which transit the Taurid orbital phase space (for more details, see Egal et al 2021).…”