Results 31 to 40 of about 917 (261)
Solar activity cycle 25: the first three years
Solar-Terrestrial Physics, 2023 We analyze features of current solar activity cycle 25 for the first three years of its development (2020–2022). Compared to cycle 24, the current cycle is shown to exceed the previous one in the number of sunspot groups (1.5 times), the number of flares
Yazev S. A. +2 more
doaj +1 more source
Sunspot groups at high latitude [PDF]
Monthly Notices of the Royal Astronomical Society, 2000 Data of sunspot groups at high latitude (greater than or equal to 35 degrees), from the year 1874 to the present (2000 January), are collected to show their evolutional behaviour and to investigate features of the yearly number of sunspot groups at high latitude.
L. Kejun +4 more
openaire +1 more source
On the size distribution of spots within sunspot groups
, 2021 The size distribution of sunspots provides key information about the generation and emergence processes of the solar magnetic field. Previous studies of size distribution have primarily focused on either the whole group or individual spot areas.
Cameron, R. +7 more
core +1 more source
A Recount of Sunspot Groups on Staudach’s Drawings [PDF]
Solar Physics, 2016 We have examined the more than 1100 drawings of the solar disk made by the German astronomy amateur Johann Caspar Staudach during 1749-1799 and counted the spots on each image. Using the modern perception of how to group spots into active regions we regrouped the spots as a modern observer would.
openaire +2 more sources
Sunspot Count Periodicities in Different Zurich Sunspot Group Classes Since 1986 [PDF]
Solar Physics, 2014 Accepted Solar Physics ...
Kilcik, A. +3 more
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Automated McIntosh-Based Classification of Sunspot Groups Using MDI Images
, 2007 YesThis paper presents a hybrid system for automatic detection and McIntosh-based classification of sunspot groups on SOHO/MDI white-light images using active-region data extracted from SOHO/MDI magnetogram images.
T. Colak +3 more
core +2 more sources
The Contribution of Large Recurrent Sunspot Groups to Solar Activity: Empirical Evidence
Universe, 2022 We identify large sunspot nestlets (SN) mostly containing recurrent sunspot groups and investigate the indices of solar activity defined as the 11- or 22-year moving average of the daily areas of the SN. These nestlets, 667 in total, are constructed from
Alexander Shapoval
doaj +1 more source
ON FLARE PREDICTABILITY BASED ON SUNSPOT GROUP EVOLUTION [PDF]
The Astrophysical Journal, 2015 The forecast method introduced by Korsós et al.(2014) is generalised from the horizontal magnetic gradient (GM), defined between two opposite polarity spots, to all spots within an appropriately defined region close to the magnetic neutral line of an active region.
M. B. Korsós +3 more
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Flare-production potential associated with different sunspot groups
, 2017 In this study, we analysed different types (C, M, and X classes) of X-ray solar flares occurring in sunspot groups. The data cover 1996-2014 time interval, and a total of 4262 active regions (ARs) were included in the data set. We defined the solar-flare-
Yurchyshyn, V. +6 more
core +1 more source
Temporal Distribution of Solar Cycle 24 Sunspot Groups: Comparison to Cycles 12-23
, 2021 We analyze the temporal distribution of sunspot groups for even and odd cycles in the range SC12- SC24. It seems that cycle 24 is a characteristic even cycle, although with low amplitude.
Takalo, Jouni J. +1 more
core +1 more source