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Sahara Meteorite Points to Moon‑Size Lost Protoplanet

A peer‑reviewed mineral pressure analysis finds the angrite NWA 12774 crystallized at roughly 17.5 kilobars, implying a parent body far larger than an asteroid.

Overview

  • Researchers measured aluminum‑rich clinopyroxene in NWA 12774 and used a newly developed geobarometer to infer crystallization pressure of about 17.5 kilobars.
  • The pressure estimate requires a parent body with a radius of at least ~1,000 km, and crystal textures that formed at shallow depth make a Moon‑ to Mars‑scale body plausible.
  • The study was published online April 10, 2026 in Earth and Planetary Science Letters after lab validation of the geobarometer against experimental data.
  • Authors stress the result rests on a small number of rare angrite specimens, temperature and depth assumptions that add roughly ±2 kilobars uncertainty, and an unresolved mechanism for how the parent body was destroyed.
  • If confirmed by more samples, the finding would show the early inner solar system produced large, now‑destroyed protoplanets and that many such bodies may still be hiding in under‑studied meteorite collections.