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) |
| 2026-03-26 00:00 |
04:08:49.78 |
-24:33:08.4 |
HIP 19374 |
28.03 |
| 2026-03-26 12:00 |
04:08:53.31 |
-24:32:07.1 |
HIP 19374 |
28.99 |
| 2026-03-27 00:00 |
04:08:56.88 |
-24:31:06.1 |
HIP 19374 |
29.98 |
| 2026-03-27 12:00 |
04:09:00.50 |
-24:30:05.3 |
HIP 19374 |
30.98 |
| 2026-03-28 00:00 |
04:09:04.16 |
-24:29:04.9 |
HIP 19374 |
32.00 |
| 2026-03-28 12:00 |
04:09:07.87 |
-24:28:04.7 |
HIP 19374 |
33.04 |
| 2026-03-29 00:00 |
04:09:11.63 |
-24:27:04.8 |
HIP 19374 |
34.09 |
| 2026-03-29 12:00 |
04:09:15.43 |
-24:26:05.1 |
HIP 19374 |
35.15 |
| 2026-03-30 00:00 |
04:09:19.28 |
-24:25:05.8 |
HIP 19374 |
36.23 |
| 2026-03-30 12:00 |
04:09:23.18 |
-24:24:06.7 |
HIP 19374 |
37.32 |
| 2026-03-31 00:00 |
04:09:27.12 |
-24:23:08.0 |
HIP 19374 |
38.42 |
| 2026-03-31 12:00 |
04:09:31.10 |
-24:22:09.5 |
HIP 19374 |
39.54 |
| 2026-04-01 00:00 |
04:09:35.13 |
-24:21:11.4 |
HIP 19374 |
40.66 |
| 2026-04-01 12:00 |
04:09:39.20 |
-24:20:13.5 |
HIP 19374 |
41.79 |
| 2026-04-02 00:00 |
04:09:43.31 |
-24:19:16.0 |
HIP 19374 |
42.93 |
| 2026-04-02 12:00 |
04:09:47.47 |
-24:18:18.8 |
HIP 19374 |
44.08 |
| 2026-04-03 00:00 |
04:09:51.67 |
-24:17:21.8 |
HIP 19453 |
45.18 |
| 2026-04-03 12:00 |
04:09:55.92 |
-24:16:25.2 |
HIP 19453 |
46.10 |
| 2026-04-04 00:00 |
04:10:00.20 |
-24:15:29.0 |
HIP 19666 |
46.43 |
| 2026-04-04 12:00 |
04:10:04.53 |
-24:14:33.0 |
HIP 19666 |
45.09 |
| 2026-04-05 00:00 |
04:10:08.90 |
-24:13:37.4 |
HIP 19666 |
43.75 |
| 2026-04-05 12:00 |
04:10:13.31 |
-24:12:42.1 |
HIP 19666 |
42.40 |
| 2026-04-06 00:00 |
04:10:17.76 |
-24:11:47.1 |
HIP 19666 |
41.05 |
| 2026-04-06 12:00 |
04:10:22.25 |
-24:10:52.5 |
HIP 19666 |
39.69 |
| 2026-04-07 00:00 |
04:10:26.78 |
-24:09:58.2 |
HIP 19666 |
38.33 |
| 2026-04-07 12:00 |
04:10:31.35 |
-24:09:04.3 |
HIP 19666 |
36.97 |
| 2026-04-08 00:00 |
04:10:35.96 |
-24:08:10.7 |
HIP 19666 |
35.61 |
| 2026-04-08 12:00 |
04:10:40.61 |
-24:07:17.4 |
HIP 19666 |
34.24 |
| 2026-04-09 00:00 |
04:10:45.29 |
-24:06:24.5 |
HIP 19666 |
32.86 |
| 2026-04-09 12:00 |
04:10:50.02 |
-24:05:32.0 |
HIP 19666 |
31.49 |
| 2026-04-10 00:00 |
04:10:54.78 |
-24:04:39.8 |
HIP 19666 |
30.11 |
| 2026-04-10 12:00 |
04:10:59.59 |
-24:03:48.0 |
HIP 19666 |
28.73 |
| 2026-04-11 00:00 |
04:11:04.42 |
-24:02:56.6 |
HIP 19666 |
27.34 |
| 2026-04-11 12:00 |
04:11:09.30 |
-24:02:05.5 |
HIP 19666 |
25.95 |
| 2026-04-12 00:00 |
04:11:14.21 |
-24:01:14.8 |
HIP 19666 |
24.56 |
| 2026-04-12 12:00 |
04:11:19.16 |
-24:00:24.5 |
HIP 19666 |
23.17 |
| 2026-04-13 00:00 |
04:11:24.15 |
-23:59:34.5 |
HIP 19666 |
21.77 |
| 2026-04-13 12:00 |
04:11:29.16 |
-23:58:45.0 |
HIP 19666 |
20.37 |
| 2026-04-14 00:00 |
04:11:34.22 |
-23:57:55.8 |
HIP 19666 |
18.97 |
| 2026-04-14 12:00 |
04:11:39.31 |
-23:57:07.0 |
HIP 19666 |
17.56 |
| 2026-04-15 00:00 |
04:11:44.43 |
-23:56:18.6 |
HIP 19666 |
16.16 |
| 2026-04-15 12:00 |
04:11:49.59 |
-23:55:30.6 |
HIP 19666 |
14.75 |
| 2026-04-16 00:00 |
04:11:54.78 |
-23:54:43.0 |
HIP 19666 |
13.34 |