= Meteorites and Their Parent Planets = === QB755.M465 1999, 2nd Ed, Harry Y. McSween, Jr., Cambridge University Press === ----- .'''Meteoroid''' - orbiting object in space .'''Meteor''' - object passing through atmosphere .'''Meteorite''' - recovered fragment .'''Chondrite''' - 86%, silicate and oxide minerals, looser sediment .'''Achondrite''' - 8%, igneous rock, partial melting and crystalization .'''Iron''' - 5%, nickle-iron .'''Stony Iron''' - 1%, mixed iron and rock .'''Willamette Stone''' - 12700 kg iron . maximum 72 km/s retrograde, typically 10 to 30 km/s prograde .p22 fig 1.13: meteors carried through blue ice to ablate in katabatic winds in front of mountains, a few thousands to a million years later .'''Amor''' outside Earth's radius, or overlap '''Apollo''' > 1 year '''Aten''' < 1 year .p43 Rubidium to strontium isotope ratios yield age .p48 Element ratios the same as the Sun, though less gasses and more lithium === Connection to Asteroids === -p79 1959 Pribam near Prague tracked by several cameras intended for satellite tracking .1964-1974 Smithsonian's Prarie Network, 16 cameras in 500 km radius of SE Nebraska . tracked hundreds, recovered "Lost City" in Oklahoma . Canadian network recovered "Innisfree" in Alberta . Asteroid types: S - chondrites, C - carbonaceous, D, P - dark .p120 ultramafic, like earth mantle basalt, olivine and pyroxene, rich in Mg and Fe .p192 iron phase diagram. Kamacite lower temperature BCC crystal, Taenite higher temperature (or more nickel) FCC crystal . Widmanstätten patterns from crystal growth .p243 Fig 8.6, spall ejecta from planets Jay Melosh