National Astronomical Observatory of Japan

The Emergence of the Largest Sunspots in 24 Years


The Emergence of the Largest Sunspots in 24 Years

In the latter half of October 2014, enormous sunspots emerged on the Sun. These sunspots came into view on the east (left in this image) side of the Sun on October 16. They developed as they moved with the Sun’s rotation and remained visible until October 30. When the total area of the sunspot group reached its maximum on October 26, it was large enough to hold approximately 66 Earths, making it the largest sunspot since 1990. This picture of the Sun is a composite of photos taken by the Solar Flare Telescope on October 18, 20, 24, 26 and 28.

The Enormous Sunspots were also Noticed at Mitaka Open House Day

The sunspots were visible on October 24 and 25, which were “Mitaka Open House Day.” Furthermore, those days were blessed with clear weather. A constant stream of attendees who had heard about these enormous sunspots from somewhere came to the Solar Flare Telescope’s open area asking, “I heard that we can see large sunspots?” The guests enjoyed the real-time images from the Solar Flare Telescope and the chance to observe the sunspots with their own eyes using the prepared eclipse glasses.

Large Quantity of Solar Flares also Produced

These enormous sunspots produced solar flares (explosive phenomena on the surface of the Sun). While these sunspots could be seen, we counted 6 large flares and 32 medium flares. This is the first time during this solar cycle that a single sunspot group has produced this many flares. Among these, a giant flare which occurred on October 19 was observed by the Solar Flare Telescope.

Text by:Kentaro Yaji (Solar Observatory)
Translation by: Ramsey Lundock (NAOJ)