0124611 - ASU-R 20000067 RIV DE eng J - Journal Article
Sobotka, Michal - Brandt, P. N. - Simon, G. W.
Fine structure in sunspots. III. Penumbral grains.
Astronomy & Astrophysics. Roč. 348, č. 2 (1999), s. 621-626. ISSN 0004-6361. E-ISSN 1432-0746
R&D Projects: GA AV ČR IAA3003903; GA AV ČR KSK1003601
Institutional research plan: CEZ:AV0Z1003909
Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics
Impact factor: 2.252, year: 1999

There appears to be a dividing line in the penumbra, approximately 0.7 of the distance from the umbra to the photosphere, such that most PGs outside this line move toward the photosphere, and those inside move toward the umbra.
Permanent Link: http://hdl.handle.net/11104/0022870