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

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.