| The colors of Saturn in 2022-23 (II) Photometry and images by Christophe.P |
Hi all here are the next results of the Saturn study. Polar scans are scaled by calculating the albedo of the southern part of the equatorial zone (same method than for Jupiter). I have calculated the scans for 2022 as well, and scaled them with the same value of albedo for the EZs, since I think it may not have changed in just one year ; the method have its limits but I did not made photometry in 2022. With the approach of the equinoxe, we expect to see the southern hemisphere brighten, and the northen one dim. This is indeed what can be seen in red light. However, in blue light, BOTH hemispheres have dimmed, which explains why it lost its noticeable blue tint of 2021-2022. In the other hand, the south hemisphere looks to have brightened noticeably in visible/green light, which explains why the overall southern tint turned to a pale green in 2023! More suprising however are the results in infrared, that may show a noticeable dimming of the north hemisphere in the I band, and a dimming of the whole globe in CH4! This may be an uncorrect result due to the fact that I did not make photometry in 2022, however, when I look at images I do feel that it is true. Do we have more data about this from HST or other ? For the next set, I will introduce analysis of color indices, and I will talk about the rings later.
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