Title of article :
The cratering history of asteroid (21) Lutetia
Author/Authors :
Marchi، نويسنده , , S. and Massironi، نويسنده , , M. and Vincent، نويسنده , , J.-B. and Morbidelli، نويسنده , , A. and Mottola، نويسنده , , S. and Marzari، نويسنده , , F. Schulze-Küppers، نويسنده , , M. and Besse، نويسنده , , S. and Thomas، نويسنده , , N. and Barbieri، نويسنده , , C. and Naletto، نويسنده , , G. and Sierks، نويسنده , , H.، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2012
Pages :
9
From page :
87
To page :
95
Abstract :
The European Space Agencyʹs Rosetta spacecraft passed by the main belt asteroid (21) Lutetia on 10th July 2010. With its ∼ 100 km size, Lutetia is one of the largest asteroids ever imaged by a spacecraft. During the flyby, the on-board OSIRIS imaging system acquired spectacular images of Lutetiaʹs northern hemisphere revealing a complex surface scarred by numerous impact craters, reaching the maximum dimension of about 55 km. s paper, we assess the cratering history of the asteroid. For this purpose, we apply current models describing the formation and evolution of main belt asteroids, that provide the rate and velocity distributions of impactors. These models, coupled with appropriate crater scaling laws, allow us to interpret the observed crater size-frequency distribution (SFD) and constrain the cratering history. Thanks to this approach, we derive the crater retention age of several regions on Lutetia, namely the time lapsed since their formation or global surface reset. We also investigate the influence of various factors – like Lutetiaʹs bulk structure and crater obliteration – on the observed crater SFDs and the estimated surface ages. ur analysis, it emerges that Lutetia underwent a complex collisional evolution, involving major local resurfacing events till recent times. The difference in crater density between the youngest and oldest recognized units implies a difference in age of more than a factor of 10. The youngest unit (Beatica) has an estimated age of tens to hundreds of Myr, while the oldest one (Achaia) formed during a period when the bombardment of asteroids was more intense than the current one, presumably around 3.6 Gyr ago or older.
Keywords :
Asteroid (21) Lutetia , Asteroid evolution , Main belt asteroids , Asteroid cratering
Journal title :
PLANETARY AND SPACE SCIENCE
Serial Year :
2012
Journal title :
PLANETARY AND SPACE SCIENCE
Record number :
2314840
Link To Document :
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