| Observer | Location | Telescope | Images/Drawings | |
|---|---|---|---|---|
| Einaga, Hideo | (Hyogo, Japan) | 25cm Refl. | 37 | images, 9 maps |
| Fukui, Hideto | (Shizuoka, Japan) | 25cm Refl. | 10 | images |
| Horikawa, Kuniaki | (Yokohama, Japan) | 16cm Refl. | 6 | drawings |
| Kazemoto, Akira | (Kyoto, Japan) | 31cm Refl. | 2 | images |
| Kumamori, Teruaki | (Osaka, Japan) | 60cm Refl. | 10 | images |
| Takimoto, Ikuo | (Kagawa, Japan) | 31cm Refl. | 3 | images |
This apparition, the emergence of South Tropical Disturbances (STrD) was reported. In a broad sense, STrD is dark shading in STrZ which progrades relative to System II, and in narrow sense, it is a dark sector in STrZ bounded by Circulating Currents. The most famous one was formed in 1901 and survived until 1939. After that, STrD emerged several times, and one which appeared in 1979 was observed by Voyager 2 in detail. These disturbances are emergence for the first time in 14 years since 1993.
Two STrDs arose at about II:0 deg., and at about II:220 deg. It is unprecedented that two STrD form simultaneously. The first one at II:0 deg. (STrD-1) was a trapezoid dark section of about 20 deg. in width, which was connected to STB by dusky bridge at the p. end. The other one at II:220 deg. (STrD-2) was a dark column of about 13 deg. in width, and was somewhat smaller than the former. Though these features were noted by typical structure for STr. Disturbance in January, both were already observed as large bulges on SEBs in Fukui's images and Horikawa's drawing on Dec. 19 and 22. Therefore, it seems that these were formed during solar conjunction.
Fortunately, New Horizons, spacecraft traveling to Pluto-Kuiper Belt, is now approaching Jupiter by chance. According to published clear images, typical curvature for South Tropical Disturbance develops at p. end of each site, and thick STBn extends tens of degrees in longitude preceding there. These features strongly imply that the circulating current forms in each site and these are independent disturbances.
As conjectured by behavior of former STrDs, the p. end of STrDs will prograde at similar rate to South Temperate Current (-0.4 deg./day), and these will expand longitudinally. It is expected to observe the circulating current, in which retrograding jetstream spots on SEBs are reflected at p. end of STrD onto STBn and they prograde with STBn jetstream. But it seems to be difficult to observe, due to weak activity of SEBs in this apparition. Also, interaction with RS will be noted when STrD reaches RS.
(2) Saturn
Saturn is retrograding in Leo, and the opposition on Feb. 10 is close at hand. Though poor condition is brought by seasonal wind of winter, it seems that seeing is better than Jupiter, because of much higher celestial declination. This month, we have received observations listed below.
| Observer | Location | Telescope | Images/Drawings | |
|---|---|---|---|---|
| Einaga, Hideo | (Hyogo, Japan) | 25cm Refl. | 6 | images |
| Hayashi, Toshio | (Kyoto, Japan) | 35cm SCT | 4 | images |
| Ikemura, Toshihiko | (Nagoya, Japan) | 31cm Refl. | 1 | image |
| Kazemoto, Akira | (Kyoto, Japan) | 31cm Refl. | 22 | images |
| Kumamori, Teruaki | (Osaka, Japan) | 60cm Refl. | 21 | images, 1 animation |
| Mishina, Toshiroh | (Yokohama, Japan) | 20cm Refl. | 4 | images |
| Phillips, Jim | (USA) | 20cm Refr. | 2 | images |
| Takimoto, Ikuo | (Kagawa, Japan) | 31cm Refl. | 40 | images |
| Tomita, Yasuaki | (Gunma, Japan) | 25cm Refl. | 1 | image |
| Yoneyama, Seiichi | (Yokohama, Japan) | 20cm Refl. | 15 | images |
| Yunoki, Kenkichi | (Osaka, Japan) | 20cm Refl. | 95 | images |
A few appearances of white spot in SEB were reported this month, too. Yunoki observed spots on Jan. 8 and 13 at about III:180 deg. and III:80 deg., respectively. And Kumamori detected a spot on Jan. 31 at about III:20 deg. Though white spot similar to Yunoki's one at III:80 deg. was observed by foreign observer, the other spots were not tracked.
Yunoki indicated that the South Pole was lighter in infrared image. Also, he stated that the opposition effect of the ring, which attracted observer's attention in recent years, may have begun, because the ring was brighter in his images on Jan. 29.
(February 13, K. Horikawa)
(Translated on March 23)
[Fig.1] Two South Tropical Disturbances arose in this apparition |
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