XRT Picture of the Week (XPOW)

XRT Home XRT Mission Ops YouTube

2018 August 17

Image Description
Click for movie.

The Sigmoid Catalog

Sigmoids, aptly named for their S-shaped structure, frequently produce both solar flares and coronal mass ejections (CMEs), which can affect life on Earth. As such, scientist study sigmoids to understand more about eruptions on the Sun, so that one day real time predictions of flares and CMEs become reality. At the Harvard-Smithsonian Center for Astrophysics (CfA), we keep a catalog of these regions. Currently, the database ends in July of 2012, so there are efforts under way to expand the database until December 2017. The new catalog contains over 300 sigmoids. Here we see an example of the long-term evolution of a sigmoid in the new catalog in four different wavelengths (or temperatures) and two different telescopes: the top right image is SDO/AIA 193 (1 million degrees Celsius) with the earth to scale, top left image is SDO/AIA 304 (50 thousand degrees Celsius), bottom right image is SDO/AIA 335 (2. 5 million degrees Celsius), and the bottom left image is Hinode/XRT (10 million degrees Celsius). Staying true to form, this sigmoid produced a flare and CME at 2016-02-05 19:02:29.

Keywords: Sigmoid, Flare, CME
Filters: Al-poly, Open

(Prepared by Jakub Prchlik)

Back Archive Next