On the Moat-Penumbra Relation

Vargas Domínguez, S.; Bonet, J. A.; Martínez Pillet, V.; Katsukawa, Y.; Kitakoshi, Y.; Rouppe van der Voort, L.
Referencia bibliográfica

The Astrophysical Journal, Volume 660, Issue 2, pp. L165-L168.

Fecha de publicación:
5
2007
Número de autores
6
Número de autores del IAC
3
Número de citas
27
Número de citas referidas
25
Descripción
Proper motions in a sunspot group with a δ-configuration and close to the solar disk center have been studied by employing local correlation tracking techniques. The analysis is based on a more than 1 hr time series of G-band images. Radial outflows with a mean speed of 0.67 km s-1 have been detected around the spots, the well-known sunspots moats. However, these outflows are not found in those umbral core sides without penumbra. Moreover, moat flows are only found in those sides of penumbrae located in the direction marked by the penumbral filaments. Penumbral sides perpendicular to them show no moat flow. These results strongly suggest a relation between the moat flow and the well-known, filament-aligned Evershed flow. The standard picture of a moat flow originating from a blocking of the upward propagation of heat is discussed in some detail.