Solar mesogranule lifetime measurements
Abstract
{ We present a study in which the solar lifetime of mesocells (4-10 arcsec) was determined from a long time sequence (6h 40min) obtained at the Pic du Midi Observatory. The mesocell detection was performed by local correlation tracking, using various spatial and temporal windows. The histograms derived from the visual measurements reveal that mesoscale lifetime is between 10min and 160min, with peaked distributions around 30-40min. The indirect method for lifetime estimation using a correlation coefficient, gives a mesocale lifetime from 16 to 185min depending on the temporal window and the methods used. The proper motions of the long-living mesocells are found to be random with respect to the superganule flows, with the peak distribution of horizontal velocities at 0.5km/s. The results of this mesocell lifetime determination method are smaller by a factor of 2 to 5 with respect to the previous results. This difference could be attributed to the mesocell definition, the method of measurement or the different location of the mesocell field of view in the supergranular network. }
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 1998
- Bibcode:
- 1998A&A...330.1136R
- Keywords:
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- SUN: PHOTOSPHERE;
- SUN: GRANULATION;
- CONVECTION