Oscillations and running waves observed in sunspots *
II. Photospheric waves
A.A. Georgakilas 1,2,
E.B. Christopoulou 1,3 and
S. Koutchmy 4
Received 20 July 2000 / Accepted 11 August 2000
To continue our study of waves related to sunspots in the photosphere, we analyzed CCD, high resolution sunspot observations obtained in the Fe I 557.6 nm line. We produced "time slice images" which reveal inward slow propagating waves in the photospheric penumbra and outward propagating waves in the area around the sunspot. The phase velocity of the waves is near 0.5 km s-1 in both cases and their horizontal wavelength about 2500 km. The waves could be related either to solar p-modes or to the subphotospheric layer large-scale convection.
Key words: Sun: sunspots Sun: oscillations
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© European Southern Observatory (ESO) 2000
Online publication: December 5, 2000