Asteroid 2023 CX1 tracked as it breaks up over France

With the support of amateur astronomers, researchers followed an asteroid’s path from space through its break-up in Earth’s atmosphere, where it scattered blazing fragments towards the ground. The observations have provided fresh insight into how these space rocks come apart.

Asteroid 2023 CX1 briefly illuminated the sky while disintegrating above north-western France at about 4:00 pm (1400 GMT) on 13 February 2023.

Seven hours before that, a Hungarian astronomer had identified the small asteroid, which measured less than a metre (yard) across and weighed 650 kilos (more than 1,400 pounds), at a distance of roughly 200,000 kilometres (125,000 miles) from Earth.

Tracking asteroid 2023 CX1’s descent

Over the ensuing minutes and hours, scientists at NASA and the European Space Agency calculated where and when it would descend with unprecedented precision.

Observatories worldwide subsequently worked together to examine every stage of its journey, deploying a variety of scientific instruments.

Professional and amateur astronomers from France’s FRIPON/Vigie-Ciel network were among those rapidly mobilised. Established around a decade ago, the network aims to detect and retrieve meteorites – asteroid fragments that reach the ground.

"We received dozens of photos and videos" of the asteroid’s seconds-long passage through the atmosphere, said Brigitte Zanda, a meteorite specialist at France’s National Museum of Natural History, which belongs to the network.

Working with members of the public, including by examining images shared on social media, enabled researchers to watch the event with "unmatched precision", Zanda told AFP.

Most notably, she said, an "extremely useful video showing the object fragmenting, which lets us see how many pieces it broke into – and how this happened" was available.

‘Brutal’ break-up

With assistance from local residents, the first meteorite, weighing 93 grams (3.3 ounces), was recovered two days later in the north-western French commune of Saint-Pierre-le-Viger.

Altogether, around a dozen meteorites were retrieved and incorporated into the museum’s collection.

All of the data collected on the asteroid was published this week in a Nature Astronomy study, two-and-a-half years after the event.

According to the study, just 11 asteroids have so far been identified before impact, with meteorites recovered from only four of those objects.

The research indicated that 2023 CX1 probably separated from a larger body in the Massalia asteroid family, located in the asteroid belt between Mars and Jupiter.

How the asteroid fragmented

Zanda said that as it entered Earth’s atmosphere, the asteroid broke apart "very brutally in two stages" at around 28 kilometres above Earth.

It shed 98 percent of its mass in the process and released an enormous amount of energy.

"This is maybe only the second time we have observed fragmentation like this," Zanda said. "It probably depends on the speed, angle of impact and internal structure of the rock."

None of the burning meteorites that reached Earth caused any damage.

Yet simulations suggested that this type of break-up could cause greater damage than a more gradual disintegration, such as that of the far larger asteroid which exploded above the Russian city of Chelyabinsk in 2013.

As that asteroid, 20 metres wide, descended, "there were five successive fragments, each releasing a small amount of energy," Zanda said.

Nevertheless, its shockwave smashed windows throughout the city and injured more than 1,000 people.

© Agence France-Presse