メタデータ
| 項目 |
値 |
| Designation |
C/2020 F8 (SWAN) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2020-05-27T13:06:40.423680Z |
| Orbit solution date (soln_date, UTC) |
2025-01-13T11:42:04Z |
| Obs used |
376 |
| NEO |
- |
| M1 |
11.600 |
| K1 |
4.500 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2020-04-24.0000000 |
| e |
0.99984071 |
| q (au) |
0.430317 |
| a (au) |
2701.498705 |
| i (deg) |
110.796078 |
| Ω (om, deg) |
260.028658 |
| ω (w, deg) |
68.198142 |
| M (ma, deg) |
359.999765 |
等級
散乱 + 全体線形
$$
M_a = (9.818 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
9.818 |
| n |
2.000 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
0.800 |
| δ90 |
1.000 |
| パラメータ |
記号 |
範囲 |
説明 |
| 太陽・地球距離が1 AUのときの絶対等級 |
H0 |
-5 to 20 |
彗星の固有の明るさ |
| 測光スロープパラメータ |
n |
2 to 6 |
太陽距離に対する明るさ変化率 |
| 前方散乱非対称係数 |
gf |
0.8 to 1 |
前方散乱の強さ |
| 後方散乱非対称係数 |
gb |
-1 to -0.5 |
後方散乱の強さ |
| 分配係数 |
k |
0.8 to 1 |
前方/後方散乱の寄与比 |
| ダスト/ガス明るさ比 |
δ90 |
1 to 10 |
ダスト散乱とガス放射の相対寄与 |
参考: EPSC-DPS2025-160
残差 (区間線形)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| 開始日 (UTC) |
終了日 (UTC) |
a |
b |
| 2019-10-22 |
2020-05-04 |
+12.2165 |
-0.587 |
| 2020-05-04 |
2020-05-26 |
-11.0290 |
-2.641 |
log10 r = log10(太陽距離/AU)、Δ = 地球距離(AU)
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
04:17:00.55 |
-23:23:39.7 |
HIP 19924 |
11.03 |
| 2026-05-12 12:00 |
04:17:06.93 |
-23:23:16.5 |
HIP 19924 |
12.30 |
| 2026-05-13 00:00 |
04:17:13.33 |
-23:22:53.9 |
HIP 19924 |
13.62 |
| 2026-05-13 12:00 |
04:17:19.73 |
-23:22:31.7 |
HIP 19924 |
14.98 |
| 2026-05-14 00:00 |
04:17:26.14 |
-23:22:10.1 |
HIP 19924 |
16.36 |
| 2026-05-14 12:00 |
04:17:32.57 |
-23:21:49.0 |
HIP 19924 |
17.75 |
| 2026-05-15 00:00 |
04:17:39.00 |
-23:21:28.4 |
HIP 19924 |
19.17 |
| 2026-05-15 12:00 |
04:17:45.45 |
-23:21:08.4 |
HIP 19924 |
20.59 |
| 2026-05-16 00:00 |
04:17:51.90 |
-23:20:48.8 |
HIP 19924 |
22.03 |
| 2026-05-16 12:00 |
04:17:58.37 |
-23:20:29.8 |
HIP 19924 |
23.47 |
| 2026-05-17 00:00 |
04:18:04.84 |
-23:20:11.3 |
HIP 20106 |
23.24 |
| 2026-05-17 12:00 |
04:18:11.32 |
-23:19:53.3 |
HIP 20106 |
22.52 |
| 2026-05-18 00:00 |
04:18:17.81 |
-23:19:35.9 |
HIP 20106 |
21.88 |
| 2026-05-18 12:00 |
04:18:24.30 |
-23:19:18.9 |
HIP 20106 |
21.34 |
| 2026-05-19 00:00 |
04:18:30.80 |
-23:19:02.5 |
HIP 20106 |
20.91 |
| 2026-05-19 12:00 |
04:18:37.31 |
-23:18:46.7 |
HIP 20106 |
20.59 |
| 2026-05-20 00:00 |
04:18:43.82 |
-23:18:31.3 |
HIP 20106 |
20.39 |
| 2026-05-20 12:00 |
04:18:50.34 |
-23:18:16.5 |
HIP 20106 |
20.30 |
| 2026-05-21 00:00 |
04:18:56.87 |
-23:18:02.2 |
HIP 20106 |
20.34 |
| 2026-05-21 12:00 |
04:19:03.39 |
-23:17:48.5 |
HIP 20106 |
20.50 |
| 2026-05-22 00:00 |
04:19:09.93 |
-23:17:35.3 |
HIP 20106 |
20.78 |
| 2026-05-22 12:00 |
04:19:16.46 |
-23:17:22.6 |
HIP 20106 |
21.18 |
| 2026-05-23 00:00 |
04:19:23.00 |
-23:17:10.5 |
HIP 20106 |
21.68 |
| 2026-05-23 12:00 |
04:19:29.54 |
-23:16:58.8 |
HIP 20106 |
22.28 |
| 2026-05-24 00:00 |
04:19:36.08 |
-23:16:47.8 |
HIP 20106 |
22.98 |
| 2026-05-24 12:00 |
04:19:42.63 |
-23:16:37.2 |
HIP 20106 |
23.75 |
| 2026-05-25 00:00 |
04:19:49.18 |
-23:16:27.2 |
HIP 20106 |
24.61 |
| 2026-05-25 12:00 |
04:19:55.73 |
-23:16:17.7 |
HIP 20106 |
25.53 |
| 2026-05-26 00:00 |
04:20:02.27 |
-23:16:08.8 |
HIP 20106 |
26.51 |
| 2026-05-26 12:00 |
04:20:08.82 |
-23:16:00.4 |
HIP 20106 |
27.54 |
| 2026-05-27 00:00 |
04:20:15.37 |
-23:15:52.5 |
HIP 20208 |
27.81 |
| 2026-05-27 12:00 |
04:20:21.92 |
-23:15:45.1 |
HIP 20208 |
28.05 |
| 2026-05-28 00:00 |
04:20:28.47 |
-23:15:38.3 |
HIP 20208 |
28.38 |
| 2026-05-28 12:00 |
04:20:35.02 |
-23:15:32.1 |
HIP 20208 |
28.80 |
| 2026-05-29 00:00 |
04:20:41.56 |
-23:15:26.4 |
HIP 20208 |
29.29 |
| 2026-05-29 12:00 |
04:20:48.11 |
-23:15:21.2 |
HIP 20208 |
29.86 |
| 2026-05-30 00:00 |
04:20:54.65 |
-23:15:16.5 |
HIP 20208 |
30.50 |
| 2026-05-30 12:00 |
04:21:01.19 |
-23:15:12.4 |
HIP 20208 |
31.21 |
| 2026-05-31 00:00 |
04:21:07.73 |
-23:15:08.8 |
HIP 20208 |
31.98 |
| 2026-05-31 12:00 |
04:21:14.26 |
-23:15:05.8 |
HIP 20208 |
32.81 |
| 2026-06-01 00:00 |
04:21:20.79 |
-23:15:03.3 |
HIP 20208 |
33.69 |
| 2026-06-01 12:00 |
04:21:27.31 |
-23:15:01.3 |
HIP 20208 |
34.62 |
| 2026-06-02 00:00 |
04:21:33.83 |
-23:14:59.9 |
HIP 20208 |
35.59 |