Moat Flow in the Vicinity of Sunspots for Various Penumbral Configurations
2008 (English)In: The Astrophysical Journal, Vol. 679, no 1, 900-909 p.Article in journal (Refereed) Published
High-resolution time series of sunspots have been obtained with the Swedish 1 m Solar Telescope between 2003 and 2006 at different locations on the solar disk. Proper motions in seven different active regions have been studied. The analysis was performed by applying local correlation tracking to every series of sunspots, each of them more than 40 minutes long. The sunspots' shapes include a different variety of penumbral configurations. We report on the systematic behavior of the large-scale outflows surrounding the sunspots, commonly known as moat flows, that are essentially present only when preceded by a penumbra not tangential but perpendicular to the sunspot border. We present one case for which this rule appears not to be confirmed. We speculate that the magnetic neutral line, which is located in the vicinity of the anomalous region, might be responsible for blocking the outflow. These new results confirm the systematic and strong relation between the moat flows and the existence of penumbrae. A comparative statistical study between moats and standard granulation is also performed.
Place, publisher, year, edition, pages
2008. Vol. 679, no 1, 900-909 p.
IdentifiersURN: urn:nbn:se:su:diva-18319DOI: doi:10.1086/587139OAI: oai:DiVA.org:su-18319DiVA: diva2:184842