Abstract
We have measured the motion of facular points and granules in the same region near a decaying sunspot. It is found that both features move away across the moat surrounding the sunspot. The mean speed of facular points is larger than that of granules: 0.65 km s−1 and 0.4 km s−1, respectively. These results are consistent with previous measurements of the speed of bright network features and moving magnetic fields, as well as of non-magnetic photospherical material. They support models in which a decaying sunspot is at the center of a supergranule, whose horizontal motions sweep out granules and magnetic flux tubes associated to the facular points. It is also found that granules are dragged by supergranular motions away of the moat.
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Contributions from the Kwasan and Hida Observatories, University of Kyoto.
A part of this work was done while one of the authors (R.M.) was staying at the Kwasan and Hida Observatories, University of Kyoto, Japan, as a JSPS research fellow.
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Muller, R., Mena, B. Motions around a decaying sunspot. Sol Phys 112, 295–303 (1987). https://doi.org/10.1007/BF00148783
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DOI: https://doi.org/10.1007/BF00148783