Scientific paper details what’s known about the third-ever interstellar object

When the news began to spread on July 1, 2025, about a new object that was spotted from the outside of our solar system, only the third of its kind, still known, the astronomers of Michigan State University – with a team of international researchers – have turned their telescopes to capture data on the new celestial observation.

The team has rushed to write a scientific article on what they know so far on the object, now called 3i / Atlas, after the latest NASA, or Atlas alert system. Atlas consists of four telescopes – two in Hawaii, one in Chile and one in South Africa – which automatically scans the whole sky several times every night in search of objects in motion.

Research is published on the arxiv pre -printed server.

Darryl Seligman of MSU, member of the scientific team and deputy professor at the College of Natural Science, took the lead in the newspaper.

“I have heard of the object before going to bed, but we did not yet have much information,” said Seligman. “As I woke up around 1 am, my colleagues, Marco Micheli of the Southern European Observatory and Davide Farnocchia from the NASA propulsion laboratory, had sent me an email that this was probably for real.

“I started sending messages by telling everyone to turn their telescopes to watch this object and I started writing the newspaper to document what we know to date. We have data from the whole world about this object.”

The discovery

Larry Denneau, member of the Atlas team, examined and submitted the observations to discover the very large telescope of the Southern European Observatory in Chile shortly after his observation on the night of July 1.

Denneau said he was prudent with caution. “We have had false alarms in the past on interesting objects, so we know not to be too excited on the first day. But the incoming observations were all consistent, and late at night, it seemed that we had the real thing.

“It is particularly rewarding that we have found it in the Milky Way towards the Galactic Center, which is a very difficult place to study for asteroids due to all stars in the background,” said Denneau. “Most of the other surveys do not look at each other.”

John Tonry, another member of Atlas and professor at the University of Hawaii, played a decisive role in the design and construction of Atlas, the investigation which discovered 3i. Tonry said: “It is really rewarding each time our hard work on the sky discovers something new, and this comet that has been traveling for millions of years from another star system is particularly interesting.”

Once 3i / Atlas has been confirmed, Seligman and Karen Meech, president of the faculty for the Astronomy Institute of the University of Hawaii, both managed the communication flow and worked on the reduction of data to submit the document.

“Once 3i / Atlas was identified as probably interstellar, we mobilized quickly,” said Meech. “We have activated the observation time on major installations such as the Southern astrophysical research telescope and the Gemini Observatory to capture early and high quality data and build a base for detailed monitoring studies.”

After confirmation of the interstellar object, institutions around the world began to share information on 3i / Atlas with Seligman.

What scientists know on 3i / Atlas so far

Although the data flock to the discovery, it is always so far from the earth, which leaves many unanswered questions. Here is what the scientific team knows at this point:

• This is only the third interstellar object (meaning from the outside of our solar system) to detect through our solar system.
• It is potentially giving gas like other comets, but it must be confirmed.
• It moves very quickly at 60 kilometers per second, or 134,000 miles per hour, compared to the sun.
• It is on an orbital path which is in the form of a boomerang or hyperbola.
• It’s very brilliant.
• It is on a path that will leave our solar system and will not return, but scientists will be able to study it for several months before its departure.

The James Webb space telescope and the Hubble space telescope should reveal more information about its size, its composition, its spin and how it reacts to be heated in the coming months.

“We have these 3i / Atlas images where he is not entirely clear and he looks more vague than the other stars of the same image,” said James Wray, professor at Georgia Tech. “But the object is far enough and, therefore, we simply do not know.”

Seligman and his team are specifically interested in the brightness of 3i / Atlas because he informs us of the evolution of coma, a cloud of dust and gas. They followed it to see if it has changed over time when the object moves and turns into space. They also want to monitor sudden lighting events in which the object becomes much brighter.

“3i / Atlas probably contains ICEs, especially below the surface, and these ice cream can start to activate when approaching the sun,” said Seligman. “But until we detect specific gas emissions, such as H₂o, Co or Co₂, we cannot say with certainty what types of ice or how much is there.”

The discovery of 3i / Atlas is only the beginning. For Tessa FRINCKE, who came to MSU at the end of June to start her career as a doctoral student at Seligman, the possibility of analyzing 3i / Atlas data to predict his future path could lead to his publication of a scientific article.

“I had to learn a lot quickly and I was shocked by the number of people involved,” said FRINCKE. “Discoveries like this have a domino effect that inspires engineering and mission planning.”

For Atsuhiro Yaginuma, a fourth year undergraduate student in the Seligman team, this discovery inspired him to apply his current research to see if it is possible to launch a spaceship from the earth to obtain it less than hundreds of kilometers or kilometers at 3i / Atlas to capture certain images and learn more about the object.

“The closest approach to earth will be in December,” said Yaginuma. “This would require a lot of fuel and a lot of rapid mobilization on the part of people here on earth. But getting closer to an interstellar object could be a unique opportunity.”

“We cannot continue to do this research and experiment with new ideas from Fricke and Yaginuma without federal funding,” said Seligman, who is also a postdoctoral member of the National Science Foundation.

Seligman and Aster Taylor, who is a former student of Seligman and now a doctoral candidate in astronomy and astrophysics and in 2023 Fannie and John Hertz Foundation Fellow, wrote the following: “At a critical moment, given the current discussions on the congression on the financing of the sciences, 3i / Atlas also reminds us for astronomy – we are supported. entirely by government and philanthropic funding.

“The fact that this science is not funded by a commercial enterprise indicates that our field does not provide a return on financial investment, but rather responds to the curiosity of the public for the deep questions of the public: where do we come from? Are we alone? What is other? The federal budget, is the reason that astronomy exists.”