TY - CHAP
T1 - Size distribution of asteroids and old terrestrial craters
T2 - Implications for asteroidal dynamics during LHB
AU - Ito, Takashi
AU - Strom, Robert G.
AU - Malhotra, Renu
AU - Yoshida, Fumi
AU - Kring, David A.
N1 - Publisher Copyright:
© 2006 by World Scientific Publishing Co. Pte. Ltd. All rights reserved.
Copyright:
Copyright 2016 Elsevier B.V., All rights reserved.
PY - 2006/1/1
Y1 - 2006/1/1
N2 - Recent progress in asteroid surveys has revealed the fine structures down to sub-km in diameter of the size-frequency distributions (SFD) of main belt asteroids (MBAs), as well as near-Earth asteroids (NEAs). These SFDs can be compared with the SFD of lunar and planetary crater projectiles. The SFD of the projectiles that created the oldest craters on the lunar highlands, which are considered a fossil of the Late Heavy Bombardment (LHB) impactors of ~4Ga ago, shows a very good agreement with that of the current MBAs. This fact indicates that the LHB craters were created by the bombardment of ancient asteroids ejected from the main belt by a short-term, size-independent event, such as the radial movement of strong resonances due to the migration of giant jovian planets. On the other hand, the SFD of the projectiles that have created younger craters such as those on Mars is very different from that of the MBAs; instead, it is quite similar to the SFD of NEAs. This newer population of projectiles might be created by a long-term, size-dependent transportation mechanism of asteroids such as the Yarkovsky effect, which preferentially pushes smaller objects into strong resonances.
AB - Recent progress in asteroid surveys has revealed the fine structures down to sub-km in diameter of the size-frequency distributions (SFD) of main belt asteroids (MBAs), as well as near-Earth asteroids (NEAs). These SFDs can be compared with the SFD of lunar and planetary crater projectiles. The SFD of the projectiles that created the oldest craters on the lunar highlands, which are considered a fossil of the Late Heavy Bombardment (LHB) impactors of ~4Ga ago, shows a very good agreement with that of the current MBAs. This fact indicates that the LHB craters were created by the bombardment of ancient asteroids ejected from the main belt by a short-term, size-independent event, such as the radial movement of strong resonances due to the migration of giant jovian planets. On the other hand, the SFD of the projectiles that have created younger craters such as those on Mars is very different from that of the MBAs; instead, it is quite similar to the SFD of NEAs. This newer population of projectiles might be created by a long-term, size-dependent transportation mechanism of asteroids such as the Yarkovsky effect, which preferentially pushes smaller objects into strong resonances.
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U2 - 10.1142/9789812707192_0031
DO - 10.1142/9789812707192_0031
M3 - Chapter
AN - SCOPUS:84971009562
SN - 9789812569837
SP - 337
EP - 343
BT - Advances in Geosciences
PB - World Scientific Publishing Co.
ER -