2023 CX1, formerly known as Sar2667, was a meter-sized asteroid that entered Earth’s atmosphere on 13 February 2023 at 03:00 UTC, and disintegrated over the English Channel near Normandy, France. It was discovered less than seven hours before impact by Hungarian astronomer Kristian Sarniczky, at the Konkoli Observatory’s Pszkisteto station in the Matra Mountains, Hungary. 2023 CX1 is the seventh asteroid to be discovered before it was successfully predicted to collide with Earth. 2023 CX1 was originally a near-Earth asteroid in a transiting Apollo-type orbit.
During a routine search for near-Earth objects using his 0.6 m (2.0 ft) Schmidt telescope, Kristian Sarnieczky first imaged asteroid 2023 CX1 on 12 February 2023 at 20:18 UTC, when it was less than 233,000 km (145,000 miles) away. From Earth and within the orbit of the Moon at a distance of 0.61 lunar distance. When detected, it was moving rapidly across the northern hemisphere sky at an angular rate of 14 arcseconds per minute, with a radial velocity of 9 km/s (5.6 mph) toward Earth and an initial apparent force of 19.4. Sarnieczky immediately realized it was an NEO but did not realize it was on its way to colliding with Earth until he re-spotted it half an hour later. Sarniczeki gave the tentative name Sar2667 and reported the discovery to the Minor Planet Center’s Near-Earth Object Confirmation page (NEOCP), calling for further follow-up by other observatories around the world. Astronomers at the Višnjan Observatory in Tičan, Croatia, observed the asteroid at 21:03 UTC and confirmed that it was on its way to colliding with Earth.
The European Space Agency noted the impending asteroid impact, and alerted the public via social media. Sarnieczky last saw the asteroid on February 13, 2023 at 02:48:01 UTC, just under 12 minutes before impact and two minutes before it entered Earth’s shadow and became invisible at 02:50 UTC. At that point, the asteroid had brightened to 13 degrees, was moving at an extremely fast angular rate of 1.1 degrees per minute, and was at an altitude of about 13,800 km (8,600 mi) from the center of the Earth (7,400 km (4,600 mi) above Earth).
After the collision, the asteroid was announced by the Minor Planet Center and named 2023 CX1 on February 13, 2023. At least 20 observatories had astrometric observations of the meteors and sent them to the Minor Planet Center prior to the collision, totaling more than 300 astrometric locations.
2023 CX1 entered Earth’s atmosphere at 02:59:21 UTC, headed east over the coast of Normandy France, across the English Channel, and fell at an inclination of 40–50° to the vertical. Because it experienced air resistance as it entered at a high speed, it burned as a bright meteor, which was seen by witnesses from France, Britain, Belgium, the Netherlands, and northern Spain. Where more than 60 reports of meteor sightings were received by the International Meteorite Organization.
Asteroid 2023 CX1 is the seventh asteroid that was successfully detected before it collided with Earth. It is also Sarniczeki’s second discovery, following his discovery of 2022 EB5 a year earlier in March 2022.
Before impact, 2023 CX1 was moving on an Apollo-type orbit through Earth’s orbit. It orbited the Sun at an average distance of 1.63 AU (244 by 106 km; 152 by 106 mi), varying from 0.92 AU at perihelion to 2.34 AU due to its eccentric orbit. The orbit had an inclination of 3.4 degrees with respect to the ecliptic and an orbital period of 2.08 years.