A celestial body shines in the November night sky that is attracting the attention of astronomers and enthusiasts from all over the world. It’s there comet C/2025 K1 (ATLAS)a rare item that displays a golden light instead of the usual green or blue shades.
Its anomalous color, according to experts, is due to a scarcity of carbon-based compoundsthe same ones that usually determine the most common shades in comets. This composition makes it a unique specimen and, for those who manage to observe it, a spectacle of extraordinary beauty.
Discovered on May 24, 2025 by the program ATLAS (Asteroid Terrestrial-Impact Last Alert System)the comet comes from the most distant and cold regions of the Solar System, probably from the Oort clouda vast reservoir of icy fragments spinning at the edge of the Sun.
When and where to observe the golden comet C/2025 K1 (ATLAS) from Italy
The comet is currently visible in eastern skyamong constellations of Virgo and Leo. From Italy it can be observed between 2:30 and 5:30 in the morningjust before dawn.
However, it is not visible to the naked eye: his magnitudei.e. the apparent brightness, is approximately +10well beyond the natural visibility threshold (which stops around +6). You need to see it to see it a telescope or astronomical binoculars. The comet will gradually move across the sky over the course of the month, maintaining an ideal position for observation until late November.
Survival at perihelion and the closest passage to Earth
The C/2025 K1 has passed the perihelionthe closest point to the Sun, last October 8, 2025when it has reached a minimum distance of 0.33 astronomical units (about 49 million kilometers). Many astronomers feared that intense solar radiation would break it up, but the comet has resistedshowing a more compact structure than expected. Now it is gradually moving away from the Sun and closer to the Earth.
His closer passage will happen November 24, 2025approximately 1.193 astronomical unitsequal to 180 million kilometres. Even then it will not be visible without instruments, but it will represent the best opportunity to observe or photograph it with amateur telescopes.
Why the comet is golden: a question of chemistry and sunlight
The color of the cometary coma is a detail that tells a lot about the composition of the celestial body. In most cases, sunlight reacts with gases such as diatomic carbon (C₂) and the ionized carbon monoxide (CO⁺)producing the typical nuances green and blue.
Comet C/2025 K1 (ATLAS) stands out because it is almost devoid of these molecules. According to data collected by Lowell Observatoryhis hair shows extremely low carbon levels compared to the concentration of hydroxyl radicals (OH). The result is one golden huedue to sunlight reflected by dust particles, not altered by the colored gases that normally dye it.
Only two known comets, the Yanaka and the 96P/Machholz 1have a similar composition. Such a rare phenomenon that makes C/2025 K1 an object of great interest for the study of the chemical evolution of the Solar System.
A fragment of ice with distant origins
Astronomers believe the comet came from the Oort clouda remote region composed of billions of small icy nuclei orbiting at enormous distances from the Sun. These objects are considered primordial remains of the formation of the Solar System, never altered by solar heat or the inner planets.
The C/2025 K1 (ATLAS), therefore, brings with it valuable information about the original matter that gave life to the planets and moons. Every time such a comet enters the inner reaches of the Solar System, scientists have the opportunity to analyze gas and dust that has remained intact for billions of years.
There are comets that go unnoticed, and others that leave a mark. The C/2025 K1 belongs to this second category. She survived a close encounter with the Sun and transformed its faint light into a golden glow like no other. For those who have the patience to look for it in the sky, it represents a rare moment: the possibility of observing one living testimony of the origin of the Solar Systemfragile and resistant at the same time.
