メタデータ
| 項目 |
値 |
| Designation |
C/2020 U4 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2022-04-08T01:08:57.566400Z |
| Orbit solution date (soln_date, UTC) |
2024-10-05T23:12:23Z |
| Obs used |
921 |
| NEO |
- |
| M1 |
5.700 |
| K1 |
12.500 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2020-10-22T13:20:36.067200Z |
| Discovery magnitude (MPC) |
20.20 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2022-05-31.0000000 |
| e |
1.00130917 |
| q (au) |
5.353691 |
| a (au) |
-4089.389408 |
| i (deg) |
167.035866 |
| Ω (om, deg) |
120.013777 |
| ω (w, deg) |
69.541084 |
| M (ma, deg) |
0.000200 |
等級
散乱 + 全体線形
$$
M_a = (8.338 + 5.142\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
8.338 |
| n |
5.142 |
| gf |
0.996 |
| gb |
-0.733 |
| k |
0.800 |
| δ90 |
9.288 |
| 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 |
| 2019-11-09 |
2021-01-18 |
+7.7107 |
-6.501 |
| 2021-01-18 |
2022-03-24 |
-6.4323 |
+4.665 |
| 2022-07-24 |
2024-09-11 |
-0.0039 |
+0.097 |
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) |
| 2026-09-20 00:00 |
20:45:53.73 |
-14:43:52.2 |
HIP 102447 |
13.45 |
| 2026-09-20 12:00 |
20:45:44.60 |
-14:44:44.8 |
HIP 102447 |
13.72 |
| 2026-09-21 00:00 |
20:45:35.54 |
-14:45:37.2 |
HIP 102447 |
14.37 |
| 2026-09-21 12:00 |
20:45:26.56 |
-14:46:29.2 |
HIP 102447 |
15.36 |
| 2026-09-22 00:00 |
20:45:17.67 |
-14:47:20.8 |
HIP 102433 |
14.79 |
| 2026-09-22 12:00 |
20:45:08.85 |
-14:48:12.2 |
HIP 102433 |
14.30 |
| 2026-09-23 00:00 |
20:45:00.11 |
-14:49:03.2 |
HIP 102433 |
14.16 |
| 2026-09-23 12:00 |
20:44:51.46 |
-14:49:53.9 |
HIP 102433 |
14.37 |
| 2026-09-24 00:00 |
20:44:42.89 |
-14:50:44.3 |
HIP 102433 |
14.92 |
| 2026-09-24 12:00 |
20:44:34.39 |
-14:51:34.3 |
HIP 102433 |
15.76 |
| 2026-09-25 00:00 |
20:44:25.99 |
-14:52:24.0 |
HIP 102433 |
16.84 |
| 2026-09-25 12:00 |
20:44:17.66 |
-14:53:13.4 |
HIP 102433 |
18.10 |
| 2026-09-26 00:00 |
20:44:09.42 |
-14:54:02.5 |
HIP 102289 |
19.20 |
| 2026-09-26 12:00 |
20:44:01.26 |
-14:54:51.2 |
HIP 102289 |
17.65 |
| 2026-09-27 00:00 |
20:43:53.18 |
-14:55:39.6 |
HIP 102289 |
16.25 |
| 2026-09-27 12:00 |
20:43:45.19 |
-14:56:27.6 |
HIP 102289 |
15.02 |
| 2026-09-28 00:00 |
20:43:37.28 |
-14:57:15.4 |
HIP 102289 |
14.00 |
| 2026-09-28 12:00 |
20:43:29.46 |
-14:58:02.7 |
HIP 102289 |
13.24 |
| 2026-09-29 00:00 |
20:43:21.72 |
-14:58:49.8 |
HIP 102289 |
12.76 |
| 2026-09-29 12:00 |
20:43:14.07 |
-14:59:36.5 |
HIP 102289 |
12.59 |
| 2026-09-30 00:00 |
20:43:06.50 |
-15:00:22.8 |
HIP 102289 |
12.73 |
| 2026-09-30 12:00 |
20:42:59.02 |
-15:01:08.8 |
HIP 102289 |
13.17 |
| 2026-10-01 00:00 |
20:42:51.62 |
-15:01:54.5 |
HIP 102289 |
13.85 |
| 2026-10-01 12:00 |
20:42:44.31 |
-15:02:39.8 |
HIP 102289 |
14.75 |
| 2026-10-02 00:00 |
20:42:37.09 |
-15:03:24.8 |
HIP 102289 |
15.82 |
| 2026-10-02 12:00 |
20:42:29.96 |
-15:04:09.4 |
HIP 102289 |
17.01 |
| 2026-10-03 00:00 |
20:42:22.91 |
-15:04:53.7 |
HIP 102289 |
18.30 |
| 2026-10-03 12:00 |
20:42:15.95 |
-15:05:37.6 |
HIP 102289 |
19.67 |
| 2026-10-04 00:00 |
20:42:09.08 |
-15:06:21.2 |
HIP 102289 |
21.08 |
| 2026-10-04 12:00 |
20:42:02.29 |
-15:07:04.4 |
HIP 102289 |
22.53 |
| 2026-10-05 00:00 |
20:41:55.60 |
-15:07:47.2 |
HIP 102289 |
24.01 |
| 2026-10-05 12:00 |
20:41:48.99 |
-15:08:29.8 |
HIP 102289 |
25.50 |
| 2026-10-06 00:00 |
20:41:42.48 |
-15:09:11.9 |
HIP 101999 |
25.45 |
| 2026-10-06 12:00 |
20:41:36.05 |
-15:09:53.7 |
HIP 101999 |
23.76 |
| 2026-10-07 00:00 |
20:41:29.71 |
-15:10:35.1 |
HIP 101999 |
22.10 |
| 2026-10-07 12:00 |
20:41:23.46 |
-15:11:16.2 |
HIP 101999 |
20.46 |
| 2026-10-08 00:00 |
20:41:17.30 |
-15:11:56.9 |
HIP 101999 |
18.85 |
| 2026-10-08 12:00 |
20:41:11.23 |
-15:12:37.2 |
HIP 101999 |
17.26 |
| 2026-10-09 00:00 |
20:41:05.26 |
-15:13:17.2 |
HIP 101999 |
15.70 |
| 2026-10-09 12:00 |
20:40:59.37 |
-15:13:56.8 |
HIP 101999 |
14.17 |
| 2026-10-10 00:00 |
20:40:53.57 |
-15:14:36.1 |
HIP 101999 |
12.66 |
| 2026-10-10 12:00 |
20:40:47.87 |
-15:15:15.0 |
HIP 101999 |
11.19 |
| 2026-10-11 00:00 |
20:40:42.25 |
-15:15:53.5 |
HIP 101999 |
9.75 |