National Astronomical Observatory of Japan



A Huge Erupting Prominence


A Huge Erupting Prominence

On July 31, 1992 (Universal Time), a coronagraph at the Norikura Solar Observatory photographed a giant erupting prominence. The prominence first began to rise at a slow speed of 30 kilometer per second and then gradually accelerated. It became a huge arch with a height of 590,000 kilometers. At the tip of the prominence, a helical structure suggesting intricately intertwined magnetic field lines was clearly photographed. After that, the prominence moved further outwards.

A Huge Prominence Eruption Captured at Multiple Wavelengths

At the Norikura Solar Observatory, astronomers started observing from 0:43 a.m. (Universal Time) when a thick fog disappeared. The prominence started to rise at a slow speed of 30 kilometer per second, gradually accelerated, and at 1:37 a.m., it formed a gigantic arch with a height of 590,000 kilometers. By that time the top part of the prominence was accelerated to a speed of 220 kilometers per second, and moved further outward. It was clearly seen at the tip of the prominence that the magnetic field lines were intricately intertwined to form a helical structure. It is thought that this reflects the complex magnetic field structure inside the prominence.

At Norikura Solar Observatory, we observed this kind of prominence eruptions several times. But this time the phenomenon was also observed with the "Yohkoh" satellite (launched in August 1991), and the Nobeyama Radioheliograph (started observation in June 1992). Through simultaneous observation at multiple wavelengths such as the Hα line, X-rays, and radio waves, the rise and eruption of this prominence were fully captured. Below the prominence, which was observed in the Hα line and radio waves, an arcade-shaped magnetic loop structure was observed in X-rays. This led to an understanding of the magnetic field structure around prominences (Note 1).

Text by: Kentaro Yaji (Solar Science Observatory, NAOJ)
Translation by: Hiroko Tsuzuki and Ramsey Lundock (Public Relations Center, NAOJ)

(Note 1) References
“Huge prominence explosion observed in the Hα line and soft X-rays” Hideaki Miyazaki, in “Sixty Years of Norikura Solar Observatory”, 2009, p 66
“Simultaneous observations of a prominence eruption followed by a coronal arcade formation in radio, soft X-rays, and H (alpha)” Yoichiro Hanaoka et al. 1994, PASJ, 46, 205
“Our Sun Seen through the Latest Images,” Kazunari Shibata, Masamitsu Ohyama, Ayumi Asai, Hiroaki Isobe, 2011, p 93

Image Data

ObjectThe Sun (prominence)
Telescope10-cm coronagraph at Norikura Solar Observatory
InstrumentHα interference filter (3 Å half width)
Wavelength656.3 nanometers
Exposure1 second
Date1:28'25" on July 31, 1992 (Universal Time)
PhotographerHideaki Miyazaki
CreditNational Astronomical Observatory of Japan


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