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Physical Characteristics of Umbral Dots Derived from a High-Resolution Observations

Abstract

The aim of this study is to revisit the physical parameters of umbral dots (UDs) with the latest high-resolution observations and contribute to the scientific understanding of their formation and evolution. In this study, we applied a particle tracking algorithm for detecting UDs in NOAA AR 12384 observed on June 14, 2015 by the Goode Solar Telescope (GST). We analyzed average position distributions, location dependencies, and general properties of the detected total 2892 UDs separately during their life time and the periodic behavior of ten selected long-lived UDs. We found: i) the brightest, largest, fastest and most elliptic UDs tend to be located at the umbra–penumbra boundary while their lifetime does not display any meaningful location dependency, ii) average dynamic velocity of all detected UDs is about twice (0.76 km s−1) of the previously reported average values, iii) obtained trajectories from the longest-lived 354 UDs show that they have generally inward motion, iv) chosen 10 long-lived UDs generally have similar periodic behavior showing 8.5 – 32, 3.5 – 4.1, 1.5 – 1.9, and 1.1 – 1.3 minutes periodicities, v) generally, detected UDs have an elliptical shape with the averaged eccentricity of 0.29, with a 0.11 standard deviation, vi) larger UDs tend to be more elliptic and more dynamic.

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    http://www.physics.emory.edu/faculty/weeks//idl/tracking.html.

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Acknowledgements

Authors would like to thanks to referee for his/her valuable comments and suggestions that improved the manuscript seriously. The high resolution sunspot data are taken from BBSO/GST. BSO operation is supported by NJIT and US NSF AGS-1821294 grants. GST operation is partly supported by the Korea Astronomy and Space Science Institute (KASI), Seoul National University, and by strategic priority research program of CAS with grant No. XDB09000000. This study was supported by Project 117F145 awarded by the Scientific and Technological Research Council of Turkey. V.Yu. acknowledges support from AFOSR FA9550-19-1-0040, NSF AGS-1821294, AST-1614457, and NASA HGC 80NSSC17K0016 and GI 80NSSC19K0257 grants.

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Correspondence to Ali Kilcik, Vasyl Yurchyshyn or Atila Ozguc.

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Kilcik, A., Sarp, V., Yurchyshyn, V. et al. Physical Characteristics of Umbral Dots Derived from a High-Resolution Observations. Sol Phys 295, 58 (2020). https://doi.org/10.1007/s11207-020-01618-y

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Keywords

  • Sunspots, umbra
  • Sunspots, magnetic fields
  • Oscillations, solar