Scott Kenyon's terrestrial planet formation page


	*Terrestrial Planet Formation*

	Terrestrial planets are rocky planets Mercury, Venus, Earth, and Mars are mostly rock Asteroids are rocky fragments of protoplanets Terrestrial planets grow by accreting smaller objects Disk-shaped nebula of dust and gas Dust grains collide and merge Large (1 mm) dust grains fall into a thin, dusty sheet Collisions produce planetesimals 1 m to 1 km across More collisions produce planets Planets stir up the leftover planetesimals Planetesimal then collide and fragment A cascade of collisions reduces fragments to dust Planets sweep up some of the dust Radiation and a wind from the central star remove the rest Computer calculations produce Earths in 1-10 Myr Results for a small simulation without fragmentation Results for a large simulation without fragmentation Computer calculations produce lots of dust in 1-10 Myr Results for a small simulation with fragmentation Results for a large simulation without fragmentation Observations can test these models Dust from the collisional cascade is observable Dust geometry and luminosity can test the model		Debris disks are the dusty remains of planet formation. Learn more ...