Comet 3I/ATLAS moves across a dense star field. NOIRLab

A new image shows the growing tail of a comet from another star system streaking across our solar system.

The image of comet 3I/ATLAS was captured on Aug. 27 using one of the telescopes at the International Gemini Observatory in Chile during a public outreach event allowing students to work with astronomers.

The comet is only the third-known interstellar object to pass through our solar system. It poses no threat to Earth, NASA previously said.

Comet 3I/ATLAS has been photographed multiple times since its discovery in July. In early August, NASA and the European Space Agency released photos taken by the Hubble Space Telescope. It was about 277 million miles away from Earth when the telescope captured it.

The new image from the Gemini Observatory shows the comet's broad coma, or a cloud of dust and gas that forms around its nucleus as it gets closer to the sun, astronomers said in a news release. The tail spans about 1/200th of a degree in the sky. One degree is about the width of a pinky finger, according to the news release. The tail also points away from the sun.

The features are "significantly more extended than they appeared in earlier images," according to astronomers. This means that the comet has become "more active" as it travels through the inner solar system.

The main purpose of the observatory session, which allowed students and members of the public to remotely join astronomers in the control room, was to look at the wavelengths of light that emit from the comet. The wavelengths, also called a spectrum, can give scientists information about the comet's composition and chemistry, helping them understand how the comet changes while passing through the solar system, the news release said.

NASA previously said the comet is expected to make its closest approach to the sun in late October and pass between the orbits of Mars and Earth. The comet is expected to remain visible through September, then get too close to the sun to observe until it reappears on the other side of the solar body in early December.

Interstellar comets are very rare, astronomers said. Only two other examples have ever been confirmed: 1I/'Oumuamu in 2017 and 2I/Borisov in 2019.

"As 3I/ATLAS speeds back into the depths of interstellar space, this image is both a scientific milestone and a source of wonder," said Karen Meech, astronomer at the University of Hawai'i Institute for Astronomy and leader of the observation program, in a statement. "It reminds us that our Solar System is just one part of a vast and dynamic galaxy — and that even the most fleeting visitors can leave a lasting impact."


The growing tail and coma of Comet 3I/ATLAS. NOIRLab

Source