Howardites - Rocks from Vesta? Target Name:   Asteroid Vesta, Achondrite Meteorite Produced by:   NASA/JPL-Caltech/Hap McSween (University of Tennessee), and Andrew Beck and Tim McCoy (Smithsonian Institution) Copyright:  NASA Copyright Free Policy Cross Reference:   PIA15137 Date Released:  2012-01-12

• Asteroid Vesta
• Meteorites

The HED (howardite, eucrite and diogenite) meteorites are a large group of meteorites believed to originate from Vesta, a hypothesis that is consistent with current Dawn observations. Howardites are regolith breccia rocks, meaning that they formed through the grinding and fusion of rock and dust that occurs during meteor impacts on the surface of Vesta. Howardites are comprised of fragments of eucrite and diogenite of varying grain sizes, which can be seen in this picture of the Bununu howardite. This sample weighs 217 grams and was recovered in 1942 in Africa. Along with fragments of eucrite and diogenite, some howardites also contain solar wind implanted noble gasses, which confirms that they once resided on the surface of their parent body. This makes howardites a good laboratory analog for spectral and chemical measurements that will be made of the Vestan surface by Dawn.