The International Astronomical Union’s Minor Planet Center issued a circular designating a newly observed object as 3I/ATLAS, also catalogued as C/2025 N1 (ATLAS), after early measurements indicated an unusually hyperbolic path.
The circular, issued at 21:31 UT, said ATLAS Chile first detected the object under the provisional candidate label A11pl3Z. The detection came from four survey exposures, each lasting 30 seconds, taken on July 1 UT. Astronomers then searched for and obtained additional measurements, including observations made during June.
Those follow-up and pre-discovery observations were credited to Q.-Z. Ye and S. Deen. According to the Minor Planet Center, the expanded record produced an orbit that was both highly eccentric and hyperbolic, with an estimated eccentricity of about six. The circular did not present that early orbital solution as the final word. Instead, it asked observers for more measurements to improve constraints on both the trajectory and the object’s physical nature.
The available imagery also offered preliminary, rather than conclusive, indications that the object could be cometary. The center reported tentative notices of activity from three observing sites. Those reports described a marginal coma and a tail measuring roughly three arcseconds, oriented at a position angle of 280 degrees. The careful wording matters: the circular characterized the activity as tentative and continued to seek confirmation.
The observation record spans dates from June 14 through July 2 and includes entries from a wide network of stations. It combines positions and brightness measurements taken with different instruments. That breadth gave orbit calculations more than the four discovery frames alone, while the center’s request for additional data showed that continued coverage was still necessary.
The document paired the new 3I/ATLAS designation with the comet-style name C/2025 N1 (ATLAS), while preserving the observational uncertainty surrounding the object. It made no diameter estimate and did not supply the size claim contained in early discovery chatter. With the official source offering no such figure, any estimate of the object’s dimensions remains outside the verified record used for this report.
The Minor Planet Center said newly submitted observations would be published through its standard *Orbits and Observations of Comets* publication. In the meantime, it made received measurements available through the MPC Explorer and a replicated observations table.
The circular’s long observation list shows why the initial announcement was a starting point rather than an endpoint. It brought together measurements from numerous observatories while emphasizing that added astrometry could refine the orbit. As of the event date, the firm findings were the discovery sequence, the strongly hyperbolic preliminary solution and the assigned names; the apparent coma and tail remained subjects for continued observation.
