On The Relation Between Umbral Dots, Dark-cored Filaments And Light Bridges
Abstract
We present high resolution observations of the complex active region AR0484 observed close to disk center at the Dunn Solar Telescope. The field of view contains several interesting features including a number of umbral fragments, light bridges of varying width, umbral dots and dark-cored penumbral filaments. A time sequence of reconstructed g-band images and adaptive optics corrected UBF filtergrams were analyzed with the goal to compare observations with recent model predictions for sunspot fine-structure. In an umbral fragment where the field strength is relatively weak we find a large number of umbral dots. We were able to resolve substructure within umbral dots that in some cases resembles the dark lanes recently predicted by MHD simulations by Schuessler and Voegler 2006. Umbral dot substructure is also clearly revealed in images of spectral line parameters. We compare line parameters for dark-cored penumbral filaments, dark lanes observed in light bridges and the umbral dot substructure. We observe dynamic proper motion of umbral dots, including motion along a narrow lane that occurs within an umbral fragment and shows similarity to the proper motion observed in narrow light bridges. Furthermore, we study the temporal variation of spectral line parameters such as the integrated line absorption of the temperature sensitive FeI 5434 A line.
- Publication:
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American Astronomical Society Meeting Abstracts #210
- Pub Date:
- May 2007
- Bibcode:
- 2007AAS...21012002R