The Depth Dependence of Penumbral Absolute Velocities
Abstract
Penumbral line-core shifts at different heights are determined from the lines Fei 5434.5 Å, Fei 5435.2 Å, and Nii 5435.8 Å using two adjacent water vapor lines for an absolute wavelength scale. The large granular blue shift of 0.6 km s-1 for the faint Fe 5435 line from deep layers yields for the centre-side penumbra absolute velocities up to 3 km s-1. This value is much larger than velocities deduced from the bisectors of the line wings of Ni 5436 and Fe 5434, thus supporting the concern against an interpretation of the line asymmetries in term of a velocity gradient with depth.
- Publication:
-
Solar Physics
- Pub Date:
- April 1997
- DOI:
- 10.1023/A:1004941617280
- Bibcode:
- 1997SoPh..171..331B
- Keywords:
-
- Water Vapor;
- Deep Layer;
- Layer Yield;
- Velocity Gradient;
- Blue Shift