The Japan Aerospace Agency (JAXA) intends to send a research mission, DESTINY+, to a relatively near-Earth Astroid Faeton in 2024, the agency's zone should pass through the celestial body in 2028, so our planet's "potentially dangerous" neighbor is observed very carefully shortly before the start of the mission.
Faeton's rotation is reduced by 4 ms annually, and even such small changes can affect observations of DESTINY+. Knowing the exact speed of rotation, it is possible to predict the position of the asteroid in relation to the flying probe, which will allow the astronomy team to plan observations more accurately.
The rotation rate of asteroids is very rare, as long as it's only the 11th celestial body of this type, which has changed the previously recorded values, and it's also the largest of these, with an average diameter of about 5.4 km.
Using observations from 1989 to 2021, explorer Sean Marshall from the Arésibo Observatory in Puerto Rico created a model that allowed for determining the form of Faeton prior to the start of the DESTINY+ mission. However, it was found that the predictions did not match the actual data. If the model showed that the asteroid was particularly bright at one time, the maximum brightness was observed in a very different way. The scientist suggested that such discrepancies in theory and practice might be due to the change in the speed of rotation of the asteroid prior to observations in 2021. This may be due to interaction with a comet in December 2020.
According to Marshall's calculations, the optimal model is now going to increase the speed of rotation, with Faeton's rotation increasing by 4 ms per year. For a future mission, the new calculations will make it possible to predict accurately the position of the asteroid at the time of the probe's flight past it and which parts of it will be lit by the Sun at these moments.
Scientists continue to explore Faeton, and DESTINY+ will help JAXA in these investigations. However, it is now known that Faeton is large enough and close to Earth to be declared "potentially dangerous" by scientists, but he does not pose an immediate threat to the planet in the foreseeable future.