C/2026 A1 (MAPS)

Lore & Background

C/2026 A1 (MAPS) was discovered through the MAPS program using a 0.28 m f/2.2 Schmidt telescope at the AMACS1 Observatory in San Pedro de Atacama. At discovery it was magnitude 17.8 in the constellation Columba, and precovery images from December 2025 showed it at about magnitude 20. The comet brightened steadily through March 2026, reaching magnitude 10 by mid-March, and was expected to become visible in 8–10 inch telescopes a few days before perihelion. It crossed the celestial equator on 30 March 2026 and was more favorably viewed from the Southern Hemisphere.

The comet belonged to the Kreutz group. Initially thought to be part of the Pe subgroup (related to the Great Comet of 1106), its unusually long orbital period suggested it might belong to a distinct subgroup. Further research by Zdenek Sekanina and Malgorzata Krolikowska indicated it may have separated from the parent body of C/1843 D1 around 363 AD, making it part of Population I. The comet disintegrated approximately 1–5 hours before reaching perihelion on 4 April 2026. Larger debris passed behind and then in front of the Sun at 13:20 and 15:36 UT, each time 0.04 degrees from the Sun's center. Submicron dust pushed by solar radiation re-emerged post-perihelion.

Reader's Guide

C/2026 A1 (MAPS) holds significance as the most distant Kreutz sungrazer ever discovered, providing an unprecedented 81-day lead time for observations before perihelion. Its discovery by the MAPS program—led by Alain Maury, Georges Attard, Daniel Parrott, and Florian Signoret—demonstrated the value of systematic survey work for finding sungrazers far from the Sun. The comet's disintegration a few hours before perihelion, captured by CCOR-1 and SOHO–LASCO, offered a rare opportunity to study the final moments of a Kreutz comet. The JWST measurement of its nucleus at roughly 400 m in diameter made it the only Kreutz comet with a direct nucleus size determination among over 5,000 known members. Its possible link to the daylight comets of 363 AD, as suggested by Sekanina and Krolikowska, adds historical depth to its legacy. The comet's fate—breaking apart before reaching its closest solar approach—underscores the fragility of these objects and the dynamic processes that govern their lives.

Did You Know?

• C/2026 A1 was discovered at 2.056 AU from the Sun, the farthest Kreutz sungrazer ever found.
• The comet's nucleus was measured at about 400 m in diameter by JWST, the only direct measurement of a Kreutz comet nucleus.
• It may be a second-generation fragment from the Great Comet of 371 BC, specifically linked to daylight comets of 363 AD.