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Western University Physics & Astronomy Western Meteor Group
Western University Peter Brown Meteor Physics — Western University
Research › Meteorites & Their Orbits

Meteorites & Their Orbits

Rocks you can trace back to where they were born.

A freshly recovered meteorite beside a coin for scale
A fragment of the Grimsby meteorite as found during a ground search. This fragment was located using information from its associated fireball trajectory to narrow down the area on the ground to search.

Most meteorites are rocks without a return address. But if you record the fireball which produces the meteorite, you can reconstruct its orbit — and link the rock in your hand to a specific region, or even a specific family, of asteroids.

I have led or been part of teams that analysed or recovered roughly one third of all meteorites with instrumentally measured orbits. Each one is a calibration point tying a meteorite type to a birthplace in the asteroid belt.

Some of the falls we have studied

  • Tagish Lake (2000) — a pristine carbonaceous chondrite, now the most-studied Canadian meteorite and a ground-truth sample for the Hayabusa2 and OSIRIS-REx asteroid missions. Likely formed in the outer solar system near Saturn.  Full story ›
  • Hamburg (H4) most likely escaped the main asteroid belt through the 3:1 resonance with Jupiter, reinforcing an inner-belt origin for H chondrites.
  • Golden (L/LL5) fell on a high-inclination orbit that is hard to reconcile with the presumed inner-belt Flora-family source for LL chondrites.
  • Almahata Sitta / asteroid 2008 TC3 — the first asteroid detected before it hit, which turned out to be a rare Urelite meteorite but also a rubble-pile mix of other meteorite types.
  • 2023 CX1 — one of only a handful of asteroids predicted to impact and then recovered; we showed its catastrophic disruption in the atmosphere happened deeper than normal hinting at an as-yet uncharacterized but more dangerous NEA population (Egal, Brown et al. 2025, Nature Astronomy).

How precisely you need to measure a fireball to make these links is itself a research question — our orbit-uncertainty analyses are used by camera networks worldwide as they set their design requirements.

Work on this as a student

Use the JPL/CNEOS fireball catalogue to work out the orbits and physical properties of metre-sized Earth impactors.

See open projects

Key publications

  • Brown, P. et al. 2000. The fall, recovery, orbit and composition of the Tagish Lake meteorite. Science 290, 320–325.
  • Borovička, J., Spurný, P., Brown, P.G. 2015. Small near-Earth asteroids as a source of meteorites. In Asteroids IV, 257–280.
  • Egal, A., Brown, P.G. et al. 2025. Catastrophic disruption of asteroid 2023 CX1 and implications for planetary defence. Nature Astronomy.