Scientists reconstruct the history of asteroid collisions

June 2, 2016, Spanish National Research Council (CSIC)
Craters on the surface of the asteroid 21 Lutetia. Credit: ESA

An international study, in which Spain's National Research Council (CSIC) participates, reveals that asteroids have endured a multitude of impact strikes since their formation 4,565 million years ago. Scientists have reconstructed a timeline of these collisions using a physics-based model which reproduces the process through time, comparing its results with present-day information about chondrite meteorites. The work appears in the Astrophysical Journal.

According to the researchers, the size distribution of the objects which make up the belt between Mars and Jupiter indicates that these asteroids have been struck by projectiles of over 20 centimetres in size at least 100 million times. The resultant craters from these strikes are proportional to both the diameters and the velocities of these projectiles.

The information compiled on ordinary chondrites indicates that these meteorites originate from which, with a diameter of less than a few hundred kilometres, collided, giving rise to these rocks millions of years ago. "Our work allows us to make fundamental predictions on the extent of breaking up from collisions, or the level of alteration by strikes due to impacts, which the huge majority of asteroids have experienced. It also explains the observations of the degree of alteration by strikes which appear in those chondrites which reach Earth", notes Josep Maria Trigo, CSIC researcher at Catalonia's Institute of Space Studies, in the Institute of Space Science.

Craters on the surface of the asteroid 21 Lutetia. Credit: ESA

In Germany's University of Braunschweig's labs, researchers Eike Beitz and Jürgen Blum, who led the research project, have carried out the impact simulation experiments. "These have been vital to understanding the physics of the process, and key in establishing the results of the impacts made by projectiles of such a varying range of shapes and velocities which occur naturally" Trigo points out. For his part, Gabriela Parisi, from the University of La Plata (Argentina), has put the physics model into practice utilizing a series of algorithms which reproduce the series of impacts between asteroids previously outlined, and has managed to replicate the collisions timeline.

The model replicates the external features of the asteroid, 21 Lutetia, established during the visit by the European Space Agency's Rosetta Mission probe. This is an irregular-shaped asteroid with a major axis measuring 121 km. 21 Lutetia has a heavily cratered surface- one crater reaching 55km in diameter- which shows clear evidence of the numerous collisions which have occurred ever since the beginnings of the planetary system. The model published in this work predicts that, as a result of fragmentation caused by large-sized projectile collisions, asteroids have huge slabs on their surfaces. The deposits of loose dust and rubble caused by this process, otherwise known as regolith, forms a surface layer a few kilometres deep. The article concludes that it is possible that a large number of the non-differentiated meteorites, or chondrites, which have reached the Earth come from these layers of regolith.

A number of space agencies are planning exploration missions to asteroids in order to bring back samples from their surfaces. The Japanese Space Exploration Agency's Hayabusa 2 and NASA's OSIRIS Rex will visit two primitive asteroids to collect samples which they will bring back to Earth. As the CSIC astrophysicist notes, "to be able to retrieve and analyse samples of the protoplanetary disc's formative materials which are in pristine condition, we will have to find asteroids between a few hundred metres and a few kilometres in size, which are homogeneous in nature".

This video simulates a collision between two asteroids. Credit: Pablo Biazzi/Publicaciones de la Universitat Jaume I

Explore further: Clues to ancient giant asteroid found in Australia

More information: Astrophysical Journal, DOI: 10.3847/0004-637X/824/1/12

Related Stories

Researchers determine the origin of Annama meteorite

April 8, 2015

An international team led by the Spanish National Research Council (CSIC) has determined the orbit of Annama, a new characterized meteorite from a fireball occurred on April 19th 2014 at the Kola Peninsula (Russia). Researchers ...

What are asteroids made of?

September 14, 2015

What are asteroids made of? Asteroids are made mostly of rock—with some composed of clay and silicate—and different metals, mostly nickel and iron. But other materials have been found in asteroids, as well.

Recommended for you

Jupiter's moon count reaches 79, including tiny 'oddball'

July 17, 2018

Twelve new moons orbiting Jupiter have been found—11 "normal" outer moons, and one that they're calling an "oddball." This brings Jupiter's total number of known moons to a whopping 79—the most of any planet in our Solar ...

Astronomers find a famous exoplanet's doppelgänger

July 17, 2018

When it comes to extrasolar planets, appearances can be deceiving. Astronomers have imaged a new planet, and it appears nearly identical to one of the best studied gas-giant planets. But this doppelgänger differs in one ...

Dawn mission to gather more data in home stretch

July 17, 2018

As NASA's Dawn spacecraft prepares to wrap up its groundbreaking 11-year mission, which has included two successful extended missions at Ceres, it will continue to explore—collecting images and other data.

Brown dwarf detected in the CoRoT-20 system

July 16, 2018

An international group of astronomers has discovered a new substellar object in the planetary system CoRoT-20. The newly identified object was classified as a brown dwarf due to its mass, which is greater than that of the ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.