Overview
- Researchers report that the angrite meteorite NWA 12774 contains aluminum-rich clinopyroxene whose chemistry records formation at pressures of at least 17.5 kilobars, a level unattainable in small asteroids.
- The team used standard geobarometry and crystal-texture observations to infer a parent body with a minimum radius near 1,000 kilometers and a plausible size exceeding 1,800 kilometers, comparable to the Moon or approaching Mars.
- The peer-reviewed paper by Aaron S. Bell et al., published online April 10, 2026, presents these pressure and texture measurements as the strongest direct evidence that a large protoplanet once existed and later broke apart.
- Angrites are very rare volcanic meteorites and NWA 12774 preserves delicate crystal edges and chemical zoning that imply formation at relatively shallow depths within a much larger body, not deep in a small rock.
- The finding rewrites a long-standing assumption that angrites come only from small asteroids, raises the prospect of more lost embryos hiding in unstudied meteorite collections, and leaves the timing and mechanism of the parent body's destruction an open question.