Results 21 to 30 of about 21,069 (265)
Invisible sunspots and rate of solar magnetic flux emergence [PDF]
, 2007 Aims. We study the visibility of sunspots and its influence on observed values of sunspot region parameters. Methods. We use Virtual Observatory tools provided by AstroGrid to analyse a sample of 6862 sunspot regions.
Bogdan +18 more
core +2 more sources
Correlations between sunspots and their moat flows [PDF]
, 2013 Context. The presence of the moat flow around sunspots is intimately linked to the mere existence of sunspots. Aims. We characterize the moat flow (MF) and Evershed flow (EF) in sunspots to enhance our knowledge of sunspot structures and photospheric ...
Löhner-Böttcher, Johannes +1 more
core +1 more source
Temporal variations of different solar activity indices through the solar cycles 21-23 [PDF]
Serbian Astronomical Journal, 2017 Here, we compare the sunspot counts and the number of sunspot groups (SGs) with variations of total solar irradiance (TSI), magnetic activity, Ca II K-flux, faculae and plage areas.
Gäoker Ü.D. +3 more
doaj +1 more source
On the Absence of Photospheric Net Currents in Vector Magnetograms of Sunspots Obtained From Hinode (SOT/SP) [PDF]
, 2009 Various theoretical and observational results have been reported regarding the presence/absence of net electric currents in the sunspots. The limited spatial resolution of the earlier observations perhaps obscured the conclusions.
Baty +21 more
core +1 more source
Scaler mode of the Auger Observatory and Sunspots [PDF]
, 2012 Recent data from the Auger Observatory on low energy secondary cosmic ray particles are analyzed to study temporal correlations together with data on the daily sunspot numbers and neutron monitor data.
Auger Scaler Data Online +15 more
core +2 more sources
Detecting the Sun’s active region using image processing techniques
Physical Sciences and Technology, 2021 The term ‘space weather’ refers to adverse conditions on the Sun that could affect the structures of space or terrestrial technology and risk human health or life. Flares produce effects that span the electromagnetic spectrum.
A. Sarsembayeva +4 more
doaj
Automatic Recognition of Sunspots in HSOS Full-Disk Solar Images
, 2016 A procedure is introduced to recognise sunspots automatically in solar full-disk photosphere images obtained from Huairou Solar Observing Station, National Astronomical Observatories of China. The images are first pre-processed through Gaussian algorithm.
Deng, YuanYong +3 more
core +1 more source
Solar cycles: the past evolution influence [PDF]
, 2009 The so-called solar cycle is generally characterized by the quasi-periodic oscillatory evolution of the photospheric spots number. This quasi-periodic pattern has always been an intriguing question.
Alexis Klutsch +4 more
core +1 more source
Identification of beryllium hydride isotopomer lines in sunspot umbral spectra [PDF]
Serbian Astronomical Journal, 2008 A high resolution spectrum of FTS sunspot umbra of NSO/Kitt Peak was used to conduct a search for the molecular absorption lines due to BeH, BeD and BeT isotopomers. Analysis led to estimates of identification of the molecular lines of bands A - X (0,0),
Shanmugavel R. +3 more
doaj +1 more source
Journal of Space Weather and Space Climate, 2023 The Madrid Astronomical Observatory implemented a solar observation program from 1876 to 1986. In addition to sunspots, the observers at this observatory recorded other solar features such as prominences.
Aparicio Alejandro Jesús Pérez +3 more
doaj +1 more source