caa a22 4500 445345969 CHVBK 20180317142829.0 cr unu---uuuuu 170323e20110501xx s 000 0 eng 10.1007/s11207-011-9729-2 doi (NATIONALLICENCE)springer-10.1007/s11207-011-9729-2 Hamedivafa H. Physics Department, Faculty of Science, Imam Khomeini International University, 34149-16818, Qazvin, Islamic Republic of Iran aut Kinematics of Umbral Dots: Their Typical Area, Brightness and Lifetime [Elektronische Daten] [H. Hamedivafa] The statistical properties of area and brightness of umbral dots, formed in a sunspot umbra observed on 18 June 2004, are studied using an improved method of image segmentation and feature tracking algorithm. Central (peripheral) umbral dots have a typical size around 0.16 (0.17)arcsec. The brightness distribution of umbral dots shows a multi-population distribution. The brightness of the central umbral dots does not exceed 0.6I quiet. In most cases, the area of central (peripheral) umbral dots reaches its maximum 40s (150s) after their brightness maximum, respectively. The brightness of umbral dots does not show any directly proportional behavior with their lifetimes and areas. The temporal variations of some physical parameters of umbral dots are studied. It seems that these variations are not physical processes in an umbra and are correlated to the images quality (seeing variations). The lifetime distribution of umbral dots is an exponential function and central (peripheral) umbral dots have a typical half-life of about 300s (180s), respectively. Springer Science+Business Media B.V., 2011 Sunspots nationallicence Umbra nationallicence Solar Physics Springer Netherlands 270/1(2011-05-01), 75-88 0038-0938 270:1<75 2011 270 11207 https://doi.org/10.1007/s11207-011-9729-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11207-011-9729-2 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Hamedivafa H. Physics Department, Faculty of Science, Imam Khomeini International University, 34149-16818, Qazvin, Islamic Republic of Iran aut NATIONALLICENCE 773 0- Solar Physics Springer Netherlands 270/1(2011-05-01), 75-88 0038-0938 270:1<75 2011 270 11207 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer