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تسجيل مستخدم جديدHi-C Observations of Sunspot Penumbral Bright Dots
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We report observations of bright dots (BDs) in a sunspot penumbra using High Resolution Coronal Imager (Hi-C) data in 193 AA and examine their sizes, lifetimes, speeds, and intensities. The sizes of the BDs are on the order of 1arcsec and are therefore hard to identify in the Atmospheric Imaging Assembly (AIA) 193 AA images, which have 1.2arcsec spatial resolution, but become readily apparent with Hi-Cs five times better spatial resolution. We supplement Hi-C data with data from AIAs 193 AA passband to see the complete lifetime of the BDs that appeared before and/or lasted longer than Hi-Cs 3-minute observation period. Most Hi-C BDs show clear lateral movement along penumbral striations, toward or away from the sunspot umbra. Single BDs often interact with other BDs, combining to fade away or brighten. The BDs that do not interact with other BDs tend to have smaller displacements. These BDs are about as numerous but move slower on average than Interface Region Imaging Spectrograph (IRIS) BDs, recently reported by cite{tian14}, and the sizes and lifetimes are on the higher end of the distribution of IRIS BDs. Using additional AIA passbands, we compare the lightcurves of the BDs to test whether the Hi-C BDs have transition region (TR) temperature like that of the IRIS BDs. The lightcurves of most Hi-C BDs peak together in different AIA channels indicating that their temperature is likely in the range of the cooler TR ($1-4times 10^5$ K).
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