Euclid telescope discovers its first comet

The European Space Agency’s Euclid space telescope has discovered its first comet, identified during observations of the region known as the Euclid Deep Field North between September 16 and 24, 2026 (Media INAF).

The object, named C/2026 S1 (Euclid), is a long-period comet located approximately 1.3 billion kilometers from Earth, between the orbits of Jupiter and Saturn, and takes over three hundred thousand years to complete one orbit around the Sun. The discovery was confirmed on October 8, 2026 by the Minor Planet Center of the International Astronomical Union (AstroSpace.it).

The object was identified by Mikko Pöntinen, a doctoral student at the University of Helsinki and part of the Euclid collaboration’s Solar System objects working group. The researcher described the moment of discovery:

“I was thrilled to see my software flag a ‘streak’ smeared across several images” — Mikko Pöntinen, doctoral student, University of Helsinki, Euclid collaboration

Euclid was primarily designed to study dark matter and dark energy, mapping the distribution of galaxies on cosmic scales; the discovery of a comet therefore represents a side result relative to the instrument’s main mission, made possible by the fact that deep-field images cover very large portions of the sky and are also analyzed in search of moving Solar System objects.

The fact that the comet takes over three hundred thousand years to complete a full orbit around the Sun places it among objects of extremely long period, likely originating from the outermost regions of the Solar System. The confirmation on October 8 by the Minor Planet Center represents the formal step that assigns the object an official designation and places it in the international catalogs of known comets.