Science and technology

The first scientific results on the consequences of the impact

DART mission: here are the last images of the collision against the asteroid

In September, NASA's DART probe struck an asteroid millions of kilometers away and managed to divert its trajectory. Now scientists have studied the effects of the impact and released new images captured by telescopes.

22/03/2023

DART's impact against Dimorphos, which occurred on September 26, 2022 11 million kilometers from Earth, was not only the first mission to defend the planet from the threat of possible "killer rocks" ever attempted, but also offered scientists the valuable opportunity to study the debris caused by the collision and learn more about asteroids. relics of the process of formation of the solar system.

The collision was also followed by the Very Large Telescope (VLY) of the European Southern Observatory (ESO) in Chile, whose data have now allowed the publication of two studies respectively in the journals Astronomy & Astrophysics and Astrophysical Journal Letters.

The first study, led by Cyrielle Opitom of the University of Edinburgh, describes the evolution of the debris cloud for a month from the moment of the collision. The cloud initially ejected was bluer than the asteroid. This means that it was formed by very fine particles, while the structures that developed in the following hours and days (tufts, spirals and a long tail) were redder, so they were made of larger material.

The second study, led by Stefano Bagnulo of the Armagh Observatory in Northern Ireland, also saw the participation of Alberto Cellino of the National Institute of Astrophysics (INAF) and analyzed how the impact with DART changed the surface of the asteroid. According to the data collected, the celestial object became brighter immediately after the collision, with two possible explanations: the collision could have exposed pristine material and brighter than the surface, or the cloud of tiny debris that was produced is more efficient in reflecting light.

By breaking down the light from the cloud, scientists tried to analyze its chemical composition, but failed. "On Earth the same thing happens when there is the impact of a meteor, which emits a lot of dust", explains Zuri Gray, researcher at the Armagh Observatory, "but unlike Earth, there is not all the gravity that pulls all this dust towards the ground", so we see a large cloud of dust that is ejected into space and that surrounds the asteroid for a few hours immediately after the impact and "almost looks like a comet".