Yummy Solar Doughnut
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What is that dark swirl hovering just off of the edge of the Sun?
Is it a solar doughnut? No, it is the cross-section of a large
magnetic tube that is wrapped partway around the Sun. These magnetic
configurations are associated with "polar crown filaments", so named
because they appear to sit like a crown or wreath on the brow of
the Sun.
This XRT image in the C/poly filter was taken at 00:03 UT on 2007/07/13, and the feature is observed to persist for hours. In the beginning, it started as a blur, but then later formed sharper edges and some structure. This evolution may have been partly due to actual changes, but was probably also due to apparent changes because the underlying feature is rotating over the limb according to the solar rotation. As the "ropy" structure rotates over the horizon, you will observe different "slices" across it. Such magnetic configurations are important to solar physicists who want to understand the Sun's ability to store magnetic energy until an eruption or other huge release of energy occurs. (Don't be distracted by the small, sharp cigar object--- it isn't a solar zeppelin. That is merely a piece of dust on the XRT instrument.) Keywords: Cavity, Limb, Filament Filters: C_poly |
(Prepared by A. Savcheva and M. Weber.)
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