Interstellar comet ATLAS 3 shows atypical gas behavior

New analyses of the interstellar comet ATLAS 3 have revealed atypical behavior compared to comets within our solar system. Research published in the ‘Planetary Science Journal’ indicates that the gases released by the comet move at approximately half the velocity typical for solar system comets at similar distances from the Sun.

ATLAS 3, discovered on July 1, 2025, through NASA-funded ATLAS research, is the third confirmed interstellar object to enter the solar system, following ‘Oumuamua’ in 2017 and Borisov 2 in 2019. This provides astronomers with a rare opportunity to study material formed in a different planetary system.

While scientists detected common molecules such as cyanogen, tricarbon, methyldin, and carbon dioxide at distances exceeding 85,000 kilometers from the nucleus, standard models for cometary halo expansion failed to match observations. The models only became accurate when gas flow velocity was reduced by half. Additionally, researchers noted exceptionally strong neutral lines of iron and nickel, marking a significant difference from solar system comets.