C/2020 U5 (PANSTARRS)
メタデータ
| 項目 | 値 |
|---|---|
| Designation | C/2020 U5 (PANSTARRS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2022-04-27T21:03:44.562240Z |
| Orbit solution date (soln_date, UTC) | 2026-06-09T11:12:25Z |
| Obs used | 513 |
| NEO | - |
| M1 | 12.300 |
| K1 | 4.500 |
| 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) | 2022-01-02.0000000 |
| e | 0.99935524 |
| q (au) | 3.755932 |
| a (au) | 5825.303368 |
| i (deg) | 97.271131 |
| Ω (om, deg) | 107.337973 |
| ω (w, deg) | 75.415330 |
| M (ma, deg) | 359.999743 |
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 | 0.997 |
| 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 | +3.8477 | -1.840 |
| 2022-12-15 | 2024-04-09 | +7.4296 | -4.434 |
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) |
|---|---|---|---|---|
| 2026-07-29 00:00 | 19:07:32.16 | -30:55:39.4 | HIP 93923 | 8.53 |
| 2026-07-29 12:00 | 19:07:20.93 | -30:56:23.3 | HIP 93923 | 9.36 |
| 2026-07-30 00:00 | 19:07:09.74 | -30:57:06.8 | HIP 93923 | 10.72 |
| 2026-07-30 12:00 | 19:06:58.60 | -30:57:50.0 | HIP 93923 | 12.43 |
| 2026-07-31 00:00 | 19:06:47.50 | -30:58:32.8 | HIP 93923 | 14.37 |
| 2026-07-31 12:00 | 19:06:36.45 | -30:59:15.3 | HIP 93923 | 16.44 |
| 2026-08-01 00:00 | 19:06:25.45 | -30:59:57.5 | HIP 93923 | 18.59 |
| 2026-08-01 12:00 | 19:06:14.50 | -31:00:39.3 | HIP 93923 | 20.81 |
| 2026-08-02 00:00 | 19:06:03.60 | -31:01:20.7 | HIP 93667 | 21.16 |
| 2026-08-02 12:00 | 19:05:52.76 | -31:02:01.9 | HIP 93667 | 18.80 |
| 2026-08-03 00:00 | 19:05:41.96 | -31:02:42.7 | HIP 93667 | 16.47 |
| 2026-08-03 12:00 | 19:05:31.22 | -31:03:23.1 | HIP 93667 | 14.18 |
| 2026-08-04 00:00 | 19:05:20.53 | -31:04:03.2 | HIP 93667 | 11.94 |
| 2026-08-04 12:00 | 19:05:09.89 | -31:04:43.0 | HIP 93667 | 9.79 |
| 2026-08-05 00:00 | 19:04:59.32 | -31:05:22.4 | HIP 93667 | 7.77 |
| 2026-08-05 12:00 | 19:04:48.80 | -31:06:01.5 | HIP 93667 | 6.01 |
| 2026-08-06 00:00 | 19:04:38.33 | -31:06:40.2 | HIP 93667 | 4.78 |
| 2026-08-06 12:00 | 19:04:27.93 | -31:07:18.6 | HIP 93667 | 4.53 |
| 2026-08-07 00:00 | 19:04:17.58 | -31:07:56.7 | HIP 93667 | 5.37 |
| 2026-08-07 12:00 | 19:04:07.30 | -31:08:34.4 | HIP 93667 | 6.89 |
| 2026-08-08 00:00 | 19:03:57.07 | -31:09:11.8 | HIP 93667 | 8.75 |
| 2026-08-08 12:00 | 19:03:46.91 | -31:09:48.8 | HIP 93667 | 10.75 |
| 2026-08-09 00:00 | 19:03:36.81 | -31:10:25.6 | HIP 93667 | 12.82 |
| 2026-08-09 12:00 | 19:03:26.78 | -31:11:01.9 | HIP 93667 | 14.93 |
| 2026-08-10 00:00 | 19:03:16.81 | -31:11:38.0 | HIP 93667 | 17.06 |
| 2026-08-10 12:00 | 19:03:06.91 | -31:12:13.7 | HIP 93491 | 18.53 |
| 2026-08-11 00:00 | 19:02:57.07 | -31:12:49.0 | HIP 93491 | 18.09 |
| 2026-08-11 12:00 | 19:02:47.30 | -31:13:24.0 | HIP 93491 | 17.92 |
| 2026-08-12 00:00 | 19:02:37.60 | -31:13:58.7 | HIP 93450 | 17.70 |
| 2026-08-12 12:00 | 19:02:27.96 | -31:14:33.1 | HIP 93450 | 16.20 |
| 2026-08-13 00:00 | 19:02:18.40 | -31:15:07.1 | HIP 93450 | 14.86 |
| 2026-08-13 12:00 | 19:02:08.91 | -31:15:40.8 | HIP 93450 | 13.73 |
| 2026-08-14 00:00 | 19:01:59.49 | -31:16:14.2 | HIP 93450 | 12.86 |
| 2026-08-14 12:00 | 19:01:50.14 | -31:16:47.2 | HIP 93450 | 12.28 |
| 2026-08-15 00:00 | 19:01:40.87 | -31:17:19.9 | HIP 93450 | 12.04 |
| 2026-08-15 12:00 | 19:01:31.67 | -31:17:52.3 | HIP 93450 | 12.14 |
| 2026-08-16 00:00 | 19:01:22.54 | -31:18:24.3 | HIP 93450 | 12.58 |
| 2026-08-16 12:00 | 19:01:13.49 | -31:18:56.0 | HIP 93450 | 13.30 |
| 2026-08-17 00:00 | 19:01:04.52 | -31:19:27.4 | HIP 93450 | 14.26 |
| 2026-08-17 12:00 | 19:00:55.62 | -31:19:58.5 | HIP 93450 | 15.41 |
| 2026-08-18 00:00 | 19:00:46.80 | -31:20:29.3 | HIP 93450 | 16.70 |
| 2026-08-18 12:00 | 19:00:38.06 | -31:20:59.7 | HIP 93450 | 18.09 |
| 2026-08-19 00:00 | 19:00:29.40 | -31:21:29.8 | HIP 93450 | 19.57 |