Scientists at the Planetary Science Institute, Carnegie Institution for Science and Lowell Observatory have determined that a mysterious object found in the main asteroid belt in 2021 is a rare comet. The findings are published in the journal Research Notes of the AAS.

Main Belt comets are icy bodies located between the orbits of Mars and Jupiter that exhibit comet-like features such as tails and dust clouds caused by the evaporation of ice. Unlike traditional comets, these objects are located in the warm interior of the solar system rather than in its cold fringes. They belong to the group of active asteroids, which may show similar activity caused by either impacts or rapid rotation.

To confirm the nature of object 456P/PANSTARRS, scientists made observations of it with the Magellan Baade and Lowell Discovery telescopes in October 2024. These observations captured the object's repetitive activity, linking it to the ice vaporization process that distinguishes comets from other active asteroids.

A key factor in identifying 456P/PANSTARRS as a main-belt comet was the observation of its regular dust emissions as it approached the Sun. This confirms that the object's activity is caused by heating and evaporation of ice, rather than single events such as collisions or physical changes. Based on the data, the scientists concluded that 456P/PANSTARRS is originally an icy body similar to classic comets from the outer solar system.

The authors of the paper note that few confirmed main-belt comets are known yet, but studying them is an important step in understanding the distribution and evolution of ice in the solar system. More observations will provide a more complete picture of their properties, such as size, activity, and localization in the asteroid belt.