The Origen of chondritic meteoroids from undifferentiated asteroids

PARISI, M. G.; E. TRIGO-RODRIGUEZ; J. BLUM; E. BEITZ

Braunschweig

Seminario; Seminat at IGeP TU; 2017

TU (Technische Universitat Braunschweig) IGeP

Most meteorites are called chondrites. The consolidation of pre-chondrites is achived during the collisional evolution of their parent objects until they are finally realeased from the Asteroid Belt. Constraints on the primordial parent objects of chondrites:-Collision Velocities in the AB are 3-5 km/s (de Elía y Brunini 2007) -Collisional  destruction lifetime for bodies with radius <35 km is 3.8-4.5 Gyrs  (de Elía y Brunini 2007, Parisi 2013).  -Sucessive impacts during the age of the Solar System compacts small Asteroids to nul porosity.-Large bodies are subject to hydrostatic compression in their interior that lead to a compaction of material with density increasing towards the center. For Φ initial =0.3-0.7, the radius of asteroids in Hid. Equ. Is > 135-268 km. Then, Chondrites primordial undifferentiated parent objects must be larger than 35 Km and smaller than 200 km in Radius!-We find that chondritic meteoroids originate most likely not from large, regolith covered objects, but from smaller regolith-free fragments of initially large asteroids (of radius >35 km < 200 km).- The size of the smaller regolith-free  fragments (of radius > 300 m < 35 km) must have a collisional destruction lifetime  larger than the CREA (10-20 Myrs, which is the same order than the lifetime in the Resonances+Neos space).   - We find that the overall surface profile of the simulated Asteroid of initial radius 100 km and  Φ=0.6 is consistent with     that of asteroid (21) Lutelia , which supports the assumption that asteroids were formed as large, almost spherical porous objects.