77au discoveredbyguiseppepiazziin1801

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Unformatted text preview: More than 20,000 Main Belt asteroids have wellknown orbital parameters • The number known has been recently increasing by a few thousand per year because of new telescopic search programs Edge on view Asteroids: The Largest Ones Asteroids: The Largest Ones 1 Ceres (1801): D = 940 km, a = 2.77 AU Discovered by Guiseppe Piazzi in 1801 Piazzi was searching for a "missing planet" between Mars and Jupiter 2 Pallas (1802): D=540 km, a=2.77 AU 4 Vesta (1807): D=510 km, a=2.36 AU 13 Main Belt asteroids have D > 250 km Asteroids: Size Distribution Asteroids: Size Distribution • The number of asteroids of a given diameter D is proportional to 1/D2 collisional distribution • For example: 3 > 500 km 13 > 250 km hundreds > 100 km 10,000+ > 10 km (?) Total: >1,000,000 > 1 km (?) Number of Near-Earth Asteroids (a model) • Most of the mass is in the largest few asteroids • Total mass of all asteroids is only ~5-10% mass of the Moon Asteroids: Gaps & Resonances Asteroids: Gaps & Resonances • Astronomer Daniel Kirkwood (1886) noticed that the Main Belt has gaps in which asteroids are “missing”. • The Kirkwood Gaps are locations where resonances with Jupiter’s orbit occur, i.e., where gravitational disturbances by Jupiter are the strongest. • May explain why no planet there: Jupiter only allowed small bodi...
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This note was uploaded on 11/10/2011 for the course GEOL 380 taught by Professor Mcsween during the Spring '11 term at University of Tennessee.

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