EarthSky
View larger. | AR 2339. Photo taken May 7, 2015 by Alan Friedman.
The current solar cycle – Cycle 24, which peaked last year – has been the weakest solar cycle recorded in over a century. During very active solar cycle peaks, the sun’s surface might be blemished with dozens or even hundreds of spots. Not so with the peak of this cycle, and, although we should still be seeing a large number of sunspots as this cycle goes into its decline, there was a day in late April when the sun showed no visible spots at all. So astronomers were glad to see this large sunspot region rotate into view on May 5. It quickly grew to a size many times larger than Earth.
Astronomers call this sunspot grouping AR 2339.
Earth compared to sunspot group AR 2339. Image via SkyandTelescope.com
Just as it was coming into view, AR 2339 released a powerful X2-class solar flare.
That flare was associated with a coronal mass ejection (CME); however, the CME was not Earth-directed. Hence, no super auroral display, at least not caused by this sunspot grouping.
But that could still happen, with AR 2339!
View larger. | C.B. Devgun in New Delhi, India submitted this photo of AR 2339 to EarthSky today (May 10, 2015). It’s AR 2339 at sunset.
EarthSky Facebook friend Abhijit Juvekar in India captured this photo earlier today – May 10, 2015. Thank you, Abhijit!
AR 2339. Photo taken May 8, 2015 by EarthSky Facebook friend Brodin Alain.
Bottom line: AR 2339 – a sunspot group many times larger than Earth – rotated into view on the sun on May 5, after a period of quiescence on the sun. It immediately produced an X-flare!
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