Comet C/2025 R2 (SWAN)

We already know the new guest of the solar system, comet C/2025 R2 (SWAN). Although it is still early, this comet is already generating excitement among amateur and professional astronomers. In this entry, we tell you what we know about him.

Who discovered it and why is it called that?

On September 11, 2025, Ukrainian amateur astronomer Vladimir Bezugly, while analyzing images from the SWAN (Solar Wind Anisotropies) instrument on board NASA and ESA's SOHO solar observatory, detected a diffuse object with an apparent magnitude of 7.4. and an impressive tail about 2 degrees long.

During its closest point to the Sun, comet C/2025 R2 (SWAN) was hidden by sunlight due to the Holetschek effect'. This effect occurs when a comet, near its perihelion, is hidden by the Sun's glare due to its low solar elongation (less than 30-35º).

Now that it has emerged, its brightness has increased rapidly, going from magnitude 11 to 6.9 in a few weeks. Astronomers believe it could maintain this brightness, although there is a chance it could disintegrate.

It bears this name because it is a non-periodic comet discovered in September 2025, the second reported in that fortnight. The name "(SWAN)" honors the SWAN instrument at the SOHO observatory, which allowed amateur astronomer Vladimir Bezugly to detect it on September 11, 2025.

Why is it so interesting?

Potential brightness: Its current magnitude (+6.9 as of September 17, 2025) and its rapid evolution (from 11 to 8 in weeks) suggest that it could reach magnitude 5.8 in October, visible with binoculars or even with the naked eye in dark skies, making it accessible to amateurs.

Single orbit: Its hyperbolic or extremely long period trajectory (thousands of years) means it is a rare traveler, possibly from the Oort cloud, offering a window into early solar system material.

Dynamic event: Its closeness to Earth (0.26 AU on October 19-20) and the possible crossing of the orbital plane on October 5, which could generate a meteor shower, add a factor of unpredictability and excitement.

Amateur discovery: The discovery by Vladimir Bezugly using SOHO data highlights the role of amateur astronomy, connecting the global community in observing this phenomenon.

What can we expect from C/2025 R2 soon?

Comet C/2025 R2 (SWAN) is full of promise, but its future is a cosmic mystery.

In the coming weeks it could maintain or even increase its current brightness of magnitude +6.9, perhaps approaching +6, which would make it easier to spot with binoculars, especially in the southern hemisphere, although northern observers could also start hunting it at dusk.

By early October its brightness could reach magnitude 5.8, perhaps visible to the naked eye in dark skies, and by October 19-20, when it is just 0.26 AU (39 million km) from Earth, its coma and tail could look spectacular... or not, if the comet disintegrates.

By November, as it crosses the celestial equator, it could be more globally accessible, but its fate depends on how it withstands solar heat.

We recommend you follow its evolution on sites such as TheSkyLive, EarthSky or NASA's APOD, where you can find fascinating data about the comet, such as its distance from Earth, the light curve, visualization of its orbit and much more.