Table 4.
Positional variation of centroids at radio frequencies for four periods.
| Bands | 101 MHz | 165 MHz | 298 MHz |
|---|---|---|---|
| (arcsec) | (arcsec) | (arcsec) | |
| I | 360 ± 78 | 332 ± 24 | 212 ± 124 |
| II | 405 ± 117 | 256 ± 61 | 254 ± 65 |
| III | 330 ± 112 | 267 ± 44 | 203 ± 40 |
| IV | 385 ± 83 | 420 ± 46 | 142 ± 31 |
| Coronal heights | 0.50 R⊙ | 0.32 R⊙ | 0.13 R⊙ |
Notes. The positional variation of centroids at radio frequencies for the four periods is shown in Fig. 8. The last row shows the coronal heights corresponding to the three frequencies based on Newkirk (1961) electron density model, assuming 4 × Ne active region coronal densities. It is important to note that the coronal heights are calculated from the solar surface.
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