C/2020 U5 (PANSTARRS)
メタデータ
| 項目 | 値 |
|---|---|
| Designation | C/2020 U5 (PANSTARRS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2022-04-27T21:04:17.325120Z |
| Orbit solution date (soln_date, UTC) | 2024-04-13T16:42:29Z |
| Obs used | 509 |
| NEO | - |
| M1 | 12.200 |
| K1 | 4.750 |
| PC | - |
| Discovery observation (MPC, UTC) | 2020-10-22T13:23:23.510400Z |
| Discovery magnitude (MPC) | 20.43 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) | 2022-01-04.0000000 |
| e | 0.99935367 |
| q (au) | 3.755932 |
| a (au) | 5811.146481 |
| i (deg) | 97.271094 |
| Ω (om, deg) | 107.337920 |
| ω (w, deg) | 75.415390 |
| M (ma, deg) | 359.999747 |
等級
散乱 + 全体線形
$$ M_a = (12.222 + 3.489\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
モデル定数
| 項目 | 値 |
|---|---|
| H0 | 12.222 |
| n | 3.489 |
| gf | 1.000 |
| gb | -0.746 |
| k | 0.800 |
| δ90 | 10.000 |
| 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 |
|---|---|---|---|
| 2020-09-25 | 2021-02-22 | -0.3995 | +0.308 |
| 2021-02-22 | 2022-04-21 | +0.9626 | -0.954 |
| 2022-04-28 | 2022-12-15 | +5.5024 | -2.816 |
| 2022-12-15 | 2023-07-15 | +1.4194 | -0.481 |
| 2023-07-15 | 2024-04-09 | +16.1704 | -10.931 |
log10 r = log10(太陽距離/AU)、Δ = 地球距離(AU)
ファインディングチャート
天体暦
| Date/Time (UTC) | RA (J2000) | Dec (J2000) | Nearest HIP | Dist from HIP (arcmin) |
|---|---|---|---|---|
| 2026-02-03 00:00 | 19:24:22.15 | -25:55:03.8 | HIP 95461 | 11.17 |
| 2026-02-03 12:00 | 19:24:32.15 | -25:55:25.6 | HIP 95461 | 9.28 |
| 2026-02-04 00:00 | 19:24:42.11 | -25:55:47.6 | HIP 95461 | 7.60 |
| 2026-02-04 12:00 | 19:24:52.04 | -25:56:09.7 | HIP 95461 | 6.33 |
| 2026-02-05 00:00 | 19:25:01.92 | -25:56:31.9 | HIP 95461 | 5.70 |
| 2026-02-05 12:00 | 19:25:11.76 | -25:56:54.2 | HIP 95461 | 5.93 |
| 2026-02-06 00:00 | 19:25:21.57 | -25:57:16.7 | HIP 95461 | 6.91 |
| 2026-02-06 12:00 | 19:25:31.33 | -25:57:39.3 | HIP 95461 | 8.39 |
| 2026-02-07 00:00 | 19:25:41.06 | -25:58:02.0 | HIP 95461 | 10.14 |
| 2026-02-07 12:00 | 19:25:50.74 | -25:58:24.9 | HIP 95461 | 12.04 |
| 2026-02-08 00:00 | 19:26:00.37 | -25:58:47.9 | HIP 95461 | 14.03 |
| 2026-02-08 12:00 | 19:26:09.97 | -25:59:11.0 | HIP 95461 | 16.06 |
| 2026-02-09 00:00 | 19:26:19.52 | -25:59:34.3 | HIP 95461 | 18.12 |
| 2026-02-09 12:00 | 19:26:29.03 | -25:59:57.7 | HIP 95655 | 17.35 |
| 2026-02-10 00:00 | 19:26:38.49 | -26:00:21.2 | HIP 95655 | 15.58 |
| 2026-02-10 12:00 | 19:26:47.91 | -26:00:44.9 | HIP 95655 | 13.94 |
| 2026-02-11 00:00 | 19:26:57.28 | -26:01:08.8 | HIP 95655 | 12.46 |
| 2026-02-11 12:00 | 19:27:06.60 | -26:01:32.8 | HIP 95655 | 11.19 |
| 2026-02-12 00:00 | 19:27:15.87 | -26:01:56.9 | HIP 95655 | 10.21 |
| 2026-02-12 12:00 | 19:27:25.10 | -26:02:21.2 | HIP 95655 | 9.61 |
| 2026-02-13 00:00 | 19:27:34.28 | -26:02:45.7 | HIP 95655 | 9.44 |
| 2026-02-13 12:00 | 19:27:43.41 | -26:03:10.3 | HIP 95655 | 9.73 |
| 2026-02-14 00:00 | 19:27:52.49 | -26:03:35.1 | HIP 95655 | 10.43 |
| 2026-02-14 12:00 | 19:28:01.52 | -26:04:00.0 | HIP 95655 | 11.46 |
| 2026-02-15 00:00 | 19:28:10.50 | -26:04:25.1 | HIP 95655 | 12.73 |
| 2026-02-15 12:00 | 19:28:19.43 | -26:04:50.3 | HIP 95655 | 14.18 |
| 2026-02-16 00:00 | 19:28:28.30 | -26:05:15.8 | HIP 95655 | 15.75 |
| 2026-02-16 12:00 | 19:28:37.12 | -26:05:41.4 | HIP 95655 | 17.40 |
| 2026-02-17 00:00 | 19:28:45.89 | -26:06:07.2 | HIP 95655 | 19.11 |
| 2026-02-17 12:00 | 19:28:54.60 | -26:06:33.1 | HIP 95655 | 20.86 |
| 2026-02-18 00:00 | 19:29:03.26 | -26:06:59.2 | HIP 95655 | 22.65 |
| 2026-02-18 12:00 | 19:29:11.86 | -26:07:25.5 | HIP 95655 | 24.45 |
| 2026-02-19 00:00 | 19:29:20.41 | -26:07:52.0 | HIP 95655 | 26.26 |
| 2026-02-19 12:00 | 19:29:28.90 | -26:08:18.7 | HIP 95655 | 28.08 |
| 2026-02-20 00:00 | 19:29:37.33 | -26:08:45.5 | HIP 95655 | 29.91 |
| 2026-02-20 12:00 | 19:29:45.71 | -26:09:12.6 | HIP 95655 | 31.73 |
| 2026-02-21 00:00 | 19:29:54.02 | -26:09:39.8 | HIP 96012 | 31.49 |
| 2026-02-21 12:00 | 19:30:02.28 | -26:10:07.2 | HIP 96012 | 30.82 |
| 2026-02-22 00:00 | 19:30:10.48 | -26:10:34.8 | HIP 96012 | 30.26 |
| 2026-02-22 12:00 | 19:30:18.61 | -26:11:02.6 | HIP 96012 | 29.82 |
| 2026-02-23 00:00 | 19:30:26.69 | -26:11:30.6 | HIP 96012 | 29.51 |
| 2026-02-23 12:00 | 19:30:34.71 | -26:11:58.8 | HIP 96012 | 29.32 |
| 2026-02-24 00:00 | 19:30:42.66 | -26:12:27.2 | HIP 96130 | 27.62 |