C/2020 U4 (PANSTARRS)
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
$$
M_a = (8.341 + 5.142\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
8.341 |
| n |
5.142 |
| gf |
0.955 |
| gb |
-0.733 |
| k |
0.800 |
| δ90 |
9.550 |
| 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 |
+7.7109 |
-6.501 |
| 2021-01-18 |
2022-03-24 |
-6.4322 |
+4.665 |
| 2022-07-24 |
2024-09-11 |
-0.0037 |
+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) |
| 2026-02-03 00:00 |
21:18:37.86 |
-11:39:21.1 |
HIP 105189 |
36.61 |
| 2026-02-03 12:00 |
21:18:45.03 |
-11:38:58.2 |
HIP 105387 |
35.33 |
| 2026-02-04 00:00 |
21:18:52.20 |
-11:38:35.2 |
HIP 105387 |
33.63 |
| 2026-02-04 12:00 |
21:18:59.36 |
-11:38:12.1 |
HIP 105387 |
31.94 |
| 2026-02-05 00:00 |
21:19:06.53 |
-11:37:48.8 |
HIP 105387 |
30.26 |
| 2026-02-05 12:00 |
21:19:13.70 |
-11:37:25.5 |
HIP 105387 |
28.59 |
| 2026-02-06 00:00 |
21:19:20.86 |
-11:37:02.0 |
HIP 105387 |
26.94 |
| 2026-02-06 12:00 |
21:19:28.02 |
-11:36:38.5 |
HIP 105387 |
25.30 |
| 2026-02-07 00:00 |
21:19:35.18 |
-11:36:14.9 |
HIP 105387 |
23.70 |
| 2026-02-07 12:00 |
21:19:42.34 |
-11:35:51.2 |
HIP 105387 |
22.12 |
| 2026-02-08 00:00 |
21:19:49.49 |
-11:35:27.4 |
HIP 105387 |
20.57 |
| 2026-02-08 12:00 |
21:19:56.63 |
-11:35:03.5 |
HIP 105387 |
19.07 |
| 2026-02-09 00:00 |
21:20:03.77 |
-11:34:39.5 |
HIP 105387 |
17.63 |
| 2026-02-09 12:00 |
21:20:10.90 |
-11:34:15.4 |
HIP 105387 |
16.25 |
| 2026-02-10 00:00 |
21:20:18.03 |
-11:33:51.3 |
HIP 105387 |
14.97 |
| 2026-02-10 12:00 |
21:20:25.14 |
-11:33:27.1 |
HIP 105387 |
13.79 |
| 2026-02-11 00:00 |
21:20:32.25 |
-11:33:02.8 |
HIP 105387 |
12.76 |
| 2026-02-11 12:00 |
21:20:39.35 |
-11:32:38.5 |
HIP 105387 |
11.91 |
| 2026-02-12 00:00 |
21:20:46.44 |
-11:32:14.1 |
HIP 105387 |
11.28 |
| 2026-02-12 12:00 |
21:20:53.53 |
-11:31:49.6 |
HIP 105451 |
9.98 |
| 2026-02-13 00:00 |
21:21:00.60 |
-11:31:25.1 |
HIP 105451 |
8.25 |
| 2026-02-13 12:00 |
21:21:07.65 |
-11:31:00.6 |
HIP 105451 |
6.55 |
| 2026-02-14 00:00 |
21:21:14.70 |
-11:30:36.0 |
HIP 105451 |
4.91 |
| 2026-02-14 12:00 |
21:21:21.73 |
-11:30:11.3 |
HIP 105451 |
3.41 |
| 2026-02-15 00:00 |
21:21:28.75 |
-11:29:46.6 |
HIP 105451 |
2.31 |
| 2026-02-15 12:00 |
21:21:35.76 |
-11:29:21.9 |
HIP 105451 |
2.31 |
| 2026-02-16 00:00 |
21:21:42.75 |
-11:28:57.1 |
HIP 105451 |
3.40 |
| 2026-02-16 12:00 |
21:21:49.73 |
-11:28:32.3 |
HIP 105451 |
4.89 |
| 2026-02-17 00:00 |
21:21:56.69 |
-11:28:07.4 |
HIP 105451 |
6.51 |
| 2026-02-17 12:00 |
21:22:03.63 |
-11:27:42.6 |
HIP 105451 |
8.19 |
| 2026-02-18 00:00 |
21:22:10.56 |
-11:27:17.7 |
HIP 105451 |
9.88 |
| 2026-02-18 12:00 |
21:22:17.47 |
-11:26:52.8 |
HIP 105451 |
11.59 |
| 2026-02-19 00:00 |
21:22:24.36 |
-11:26:27.9 |
HIP 105451 |
13.30 |
| 2026-02-19 12:00 |
21:22:31.23 |
-11:26:03.0 |
HIP 105451 |
15.02 |
| 2026-02-20 00:00 |
21:22:38.08 |
-11:25:38.0 |
HIP 105451 |
16.73 |
| 2026-02-20 12:00 |
21:22:44.92 |
-11:25:13.1 |
HIP 105451 |
18.44 |
| 2026-02-21 00:00 |
21:22:51.73 |
-11:24:48.2 |
HIP 105451 |
20.15 |
| 2026-02-21 12:00 |
21:22:58.51 |
-11:24:23.2 |
HIP 105451 |
21.85 |
| 2026-02-22 00:00 |
21:23:05.28 |
-11:23:58.3 |
HIP 105451 |
23.56 |
| 2026-02-22 12:00 |
21:23:12.02 |
-11:23:33.4 |
HIP 105451 |
25.25 |
| 2026-02-23 00:00 |
21:23:18.74 |
-11:23:08.5 |
HIP 105451 |
26.94 |
| 2026-02-23 12:00 |
21:23:25.44 |
-11:22:43.6 |
HIP 105451 |
28.63 |
| 2026-02-24 00:00 |
21:23:32.11 |
-11:22:18.8 |
HIP 105451 |
30.31 |