Comet Ikeya–Seki in the context of Kreutz sungrazers

⭐ Core Definition: Comet Ikeya–Seki

Comet Ikeya–Seki, formally designated C/1965 S1, 1965 VIII, and 1965f, was a long-period comet discovered independently by Kaoru Ikeya and Tsutomu Seki. First observed as a faint telescopic object on 18 September 1965, the first calculations of its orbit suggested that on October 21, it would pass just 450,000 km (280,000 mi) above the Sun's surface, and would probably become extremely bright.

Comets can defy such predictions, but Ikeya–Seki performed as expected. As it approached perihelion observers reported that it was clearly visible in the daytime sky next to the Sun. In Japan, where it reached perihelion at local noon, it was seen shining at magnitude −10. It proved to be one of the brightest comets seen in the last thousand years, and is sometimes known as the Great Comet of 1965.

↓ Menu

HINT:

👉 Comet Ikeya–Seki in the context of Kreutz sungrazers

The Kreutz sungrazers (/ˈkrɔɪts/ KROYTS) are a family of sungrazing comets, characterized by orbits taking them extremely close to the Sun at perihelion. At the far extreme of their orbits, aphelion, Kreutz sungrazers can be a hundred times farther from the Sun than the Earth is, while their distance of closest approach can be less than twice the Sun's radius. They are believed to be fragments of one large comet that broke up several centuries ago and are named for German astronomer Heinrich Kreutz, who first demonstrated that they were related. These sungrazers make their way from the distant outer Solar System to the inner Solar System, to their perihelion point near the Sun, and then leave the inner Solar System in their return trip to their aphelion.

Several members of the Kreutz family have become great comets, occasionally visible near the Sun in the daytime sky. The most recent of these was Comet Ikeya–Seki in 1965, which may have been one of the brightest comets in the last millennium. It has been suggested that another cluster of bright Kreutz system comets may begin to arrive in the inner Solar System in the next few decades.

↓ Explore More Topics

In this Dossier

⭐ Core Definition: Comet Ikeya–Seki
👉 Comet Ikeya–Seki in the context of Kreutz sungrazers
Comet Ikeya–Seki in the context of Heinrich Kreutz

Comet Ikeya–Seki in the context of Heinrich Kreutz

Heinrich Carl Friedrich Kreutz (September 8, 1854 – July 13, 1907) was a German astronomer, most notable for his studies of the orbits of several sungrazing comets, which revealed that they were all related objects, produced when a very large Sun-grazing comet fragmented several hundred years previously. The group is now known as the Kreutz Sungrazers, and has produced some of the brightest comets ever seen, including X/1106 C1 and Comet Ikeya–Seki. The source of the group may have been the Great Comet of 371 BC.

Kreutz was born in Siegen in 1854, and obtained his PhD at the University of Bonn in 1880 on the orbit of comet C/1861 J1. In 1882 he moved to Kiel, working at the observatory and university there. In 1896 he became the editor of the Astronomische Nachrichten, the leading astronomical journal of the time, and held the position until his death in 1907.

View the full Wikipedia page for Heinrich Kreutz

↑ Return to Menu