Comet Lemmon (C/2025 A6), discovered by the Mount Lemmon Survey, developed a visible coma and tail and was photographed above Pedraforca mountain in Spain. The image captures active sublimation — ices turning to gas and releasing dust — and shows coma colors that hint at gases fluorescing under solar UV. Scientists use such images to model dust production, tail shape, and interactions with the solar wind and radiation pressure. Bright, easily visible comets remain rare, making this observation notable.
Comet Lemmon (C/2025 A6) Streaks Above Spain's Pedraforca — Photo Captures Active Sublimation
Comet Lemmon (C/2025 A6), discovered by the Mount Lemmon Survey, developed a visible coma and tail and was photographed above Pedraforca mountain in Spain. The image captures active sublimation — ices turning to gas and releasing dust — and shows coma colors that hint at gases fluorescing under solar UV. Scientists use such images to model dust production, tail shape, and interactions with the solar wind and radiation pressure. Bright, easily visible comets remain rare, making this observation notable.
11:42 PM, 11/11/2025Science
Space photo of the day — Nov. 11, 2025
Comet Lemmon (C/2025 A6) recently graced the night sky above Spain, producing a striking image captured near the distinctive Pedraforca mountain in the Berguedà region. This rare visitor — possibly on an orbit spanning thousands of years — drew attention when it developed a visible coma and a tail, prompting reclassification after its initial, asteroid-like detection.
Discovery and classification: The object was first recorded by the Arizona-based Mount Lemmon Survey. Initially logged as a point-like object, it was reclassified as a comet when observers identified a growing coma and an emerging tail in follow-up images.
Comets are often described as "dirty snowballs": icy bodies mixed with dust and rock that originate in the solar system's distant reservoirs.
As a comet approaches the Sun, solar heating causes ices to sublimate — turning directly from solid to gas — and releasing dust and vapor that form the bright coma surrounding the nucleus and one or more tails that stream away. The photograph from Pedraforca records this active sublimation and reveals structure in the coma and tail that astronomers can analyze.
Scientific value: The color of a comet's coma can indicate which gases are fluorescing under solar ultraviolet radiation, offering clues about the ices present. Detailed images of coma and tail morphology allow researchers to model dust-production rates, reconstruct the tail's shape and length, and study interactions with the solar wind and radiation pressure. These observations help scientists probe primordial material from the era when the solar system formed.
Why this sighting matters: Advances in wide-field survey telescopes and the growing popularity of astrophotography mean more comets are discovered and documented today than in the past. Still, bright comets that are easy to spot with the unaided eye remain uncommon, making photographs like this both scientifically useful and visually memorable.
Location: Pedraforca mountain, Berguedà region, Spain — a dramatic terrestrial landmark that frames the comet against a striking landscape and helps provide scale and context for the observation.
For amateur astronomers and professional observers alike, Comet Lemmon presented an opportunity to study active sublimation and cometary composition in real time, while offering the public a rare celestial spectacle.