Just one Coronal Hole (June 22, 2007)

The main noteworthy feature on the Sun this past week is the one, dark, coronal hole that we watched as it rotated to the Sun's center over three days (June 17-19, 2007). Anyone who inspects the movie carefully will note that there were no looping arcs, no flares or solar storms, no filaments, and no bright active regions. Yes, the Sun remained largely featureless except for the coronal hole, and even that hole is not particularly large as these things go. We should note too that the north and the south poles of the Sun also have polar coronal holes that are becoming more distinct as we approach solar minimum.

Coronal holes are cooler, darker areas when observed in extreme ultraviolet light as the Sun is here. Since coronal holes are 'open' magnetically, strong solar wind gusts can escape from them and carry solar particles out to our magnetosphere and beyond. The Sun is near its minimum period of activity in its 11-year solar cycle and it shows it in this way.

SOHO began its Weekly Pick some time after sending a weekly image or video clip to the American Museum of Natural History (Rose Center) in New York City. There, the SOHO Weekly Pick is displayed with some annotations on a large plasma display.

If your institution would also like to receive the same Weekly Pick from us for display (usually in Photoshop or QuickTime format), please send your inquiry to steele.hill@gsfc.nasa.gov.