The asteroidal source of the Park Forest meteorite

Mon, 05/22/2017 - 08:58 -- pheck
Park Forest

A bit more than 14 years ago, a 2-6 ton space rock entered the Earth's atmosphere. It broke up above Chicagoland, and up to 100 kg of fragments fell into southern suburb of Park Forest, which now lends its name to the meteorite. The new study published by Matthias Meier, a researcher at the Swiss Federal Institute of Technology and a former graduate student of Robert A. Pritzker Associate Curator Philipp Heck, shows now that the meteorite has been traveling in space for 14 million years, and is also a fragment of a large asteroid (>100 km) destroyed in a big collision 470 million years ago. The same collision from which the fossil meteorites, now exhibited with Park Forest at the Field Museum, are from. Thanks to cameras which tracked the meteor as it lighted up the mid-western skies, we now know on which orbit the space rock was revolving around the Sun before it hit Earth. The Robert A. Pritzker Center for Meteoritics and Polar Studies at the Field Museum of Natural History holds the largest mass of the Park Forest meteorite and loaned a subsample of it to Matthias and co-authors. The paper is published in the journal Meteoritics & Planetary Science.

A cross sectioned specimen of the Park Forest meteorite on exhibit at the Field Museum of Natural History. (c) Copyright John Weinstein, FMNH.