Interstellar object 3IATLAS to reach perihelion near the Sun

The interstellar object known as 3IATLAS will reach its closest point to the Sun on October 29, when it passes about 1.36 to 1.4 astronomical units, roughly 210 million kilometres, from the star, astronomers say. First detected on July 1 by the ATLAS survey telescope in Chile, the object is on a hyperbolic trajectory that confirms it originated beyond the Solar System and will continue outward after this brief visit.

Observers have tracked 3IATLAS as it accelerated through the inner Solar System at tens of kilometres per second, crossing inside the orbit of Mars and remaining far from Earth. Space agencies stress the object poses no hazard: its nearest approach to Earth will be hundreds of millions of kilometres away, and its path will carry it out of the Sun’s gravitational influence. Ground telescopes already lost sight of the object while it moved behind the Sun; space telescopes and some orbiting spacecraft have continued limited monitoring and teams plan coordinated observations when it reappears in the weeks after perihelion.

Early observations by Hubble, the James Webb Space Telescope and large ground facilities show an active cometary body. Images have revealed a coma of...