Solar activity during the deep minimum of 2009

Janusz Sylwester, Marek Siarkowski, Szymon Gburek, Magdalena Gryciuk, Anna Kępa, Mirosław Kowaliński, Tomek Mrozek, Kenneth J.H. Phillips, Piotr Podgórski and Barbara Sylwester

We discuss the character of the unusually deep solar activity minimum of 2009 between Solar Cycles 23 and 24. Levels of solar activity in various parts of the solar atmosphere - photosphere, chromosphere, transition region, and corona - were observed to be at their lowest for a century. The soft X-ray emission from the corona (hot outer part of the Sun's atmosphere) was measured throughout most of 2009 with the Polish-built SphinX spectrophotometer. Unlike other Xray monitoring spacecraft, this sensitive spacecraft-borne instrument was able to continue measurements throughout this extended period of low activity.

Proceedings of the Polish Astronomical Society, vol. 1, 82-88 (2014)

Download full article as PDF file: