C/2020 V2 (ZTF)
メタデータ
| 項目 | 値 |
|---|---|
| Designation | C/2020 V2 (ZTF) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2023-05-08T13:21:29.376000Z |
| Orbit solution date (soln_date, UTC) | 2025-09-30T13:39:21Z |
| Obs used | 5767 |
| NEO | - |
| M1 | 8.700 |
| K1 | 4.500 |
| PC | - |
| Discovery observation (MPC, UTC) | 2020-11-02T12:42:20.160000Z |
| Discovery magnitude (MPC) | 19.04 r |
| Discovery observatory (MPC) | I41 · Palomar Mountain–ZTF |
オスキュレーティング軌道要素
| 項目 | 値 |
|---|---|
| Epoch (epoch_cal, TDB) | 2022-10-07.0000000 |
| e | 1.00089953 |
| q (au) | 2.227960 |
| a (au) | -2476.803384 |
| i (deg) | 131.611042 |
| Ω (om, deg) | 212.371235 |
| ω (w, deg) | 162.424317 |
| M (ma, deg) | -0.001708 |
等級
散乱 + 全体線形
$$ M_a = (8.951 + 2.985\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
モデル定数
| 項目 | 値 |
|---|---|
| H0 | 8.951 |
| n | 2.985 |
| gf | 1.000 |
| gb | -0.726 |
| 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 |
|---|---|---|---|
| 2020-04-18 | 2022-11-29 | +2.8905 | -2.125 |
| 2022-11-29 | 2023-04-18 | +1.1777 | -1.001 |
| 2023-06-12 | 2023-08-25 | +25.9574 | -10.877 |
| 2023-08-25 | 2024-05-20 | -2.9823 | +1.312 |
| 2024-05-20 | 2025-10-26 | +0.5312 | -0.877 |
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 | 18:23:20.90 | -72:27:48.6 | HIP 90094 | 33.08 |
| 2026-07-29 12:00 | 18:22:40.68 | -72:26:28.2 | HIP 89899 | 32.44 |
| 2026-07-30 00:00 | 18:22:00.79 | -72:25:06.5 | HIP 89899 | 30.37 |
| 2026-07-30 12:00 | 18:21:21.21 | -72:23:43.4 | HIP 89899 | 28.53 |
| 2026-07-31 00:00 | 18:20:41.97 | -72:22:18.9 | HIP 89899 | 26.94 |
| 2026-07-31 12:00 | 18:20:03.05 | -72:20:53.1 | HIP 89899 | 25.67 |
| 2026-08-01 00:00 | 18:19:24.47 | -72:19:26.0 | HIP 89899 | 24.75 |
| 2026-08-01 12:00 | 18:18:46.22 | -72:17:57.7 | HIP 89899 | 24.22 |
| 2026-08-02 00:00 | 18:18:08.30 | -72:16:28.0 | HIP 89899 | 24.10 |
| 2026-08-02 12:00 | 18:17:30.73 | -72:14:57.1 | HIP 89899 | 24.39 |
| 2026-08-03 00:00 | 18:16:53.51 | -72:13:24.9 | HIP 89899 | 25.08 |
| 2026-08-03 12:00 | 18:16:16.62 | -72:11:51.5 | HIP 89899 | 26.13 |
| 2026-08-04 00:00 | 18:15:40.09 | -72:10:16.9 | HIP 89899 | 27.50 |
| 2026-08-04 12:00 | 18:15:03.91 | -72:08:41.1 | HIP 88979 | 29.13 |
| 2026-08-05 00:00 | 18:14:28.08 | -72:07:04.2 | HIP 88979 | 27.86 |
| 2026-08-05 12:00 | 18:13:52.60 | -72:05:26.1 | HIP 88979 | 26.94 |
| 2026-08-06 00:00 | 18:13:17.48 | -72:03:46.8 | HIP 88979 | 26.39 |
| 2026-08-06 12:00 | 18:12:42.72 | -72:02:06.5 | HIP 88979 | 26.24 |
| 2026-08-07 00:00 | 18:12:08.33 | -72:00:25.0 | HIP 89002 | 24.08 |
| 2026-08-07 12:00 | 18:11:34.29 | -71:58:42.5 | HIP 89002 | 21.46 |
| 2026-08-08 00:00 | 18:11:00.62 | -71:56:58.9 | HIP 89002 | 18.99 |
| 2026-08-08 12:00 | 18:10:27.32 | -71:55:14.3 | HIP 89002 | 16.73 |
| 2026-08-09 00:00 | 18:09:54.39 | -71:53:28.7 | HIP 89002 | 14.78 |
| 2026-08-09 12:00 | 18:09:21.82 | -71:51:42.0 | HIP 89002 | 13.25 |
| 2026-08-10 00:00 | 18:08:49.63 | -71:49:54.4 | HIP 89002 | 12.31 |
| 2026-08-10 12:00 | 18:08:17.81 | -71:48:05.7 | HIP 89002 | 12.09 |
| 2026-08-11 00:00 | 18:07:46.36 | -71:46:16.2 | HIP 89002 | 12.61 |
| 2026-08-11 12:00 | 18:07:15.29 | -71:44:25.7 | HIP 89002 | 13.78 |
| 2026-08-12 00:00 | 18:06:44.60 | -71:42:34.3 | HIP 89002 | 15.44 |
| 2026-08-12 12:00 | 18:06:14.28 | -71:40:42.0 | HIP 89002 | 17.46 |
| 2026-08-13 00:00 | 18:05:44.34 | -71:38:48.9 | HIP 89002 | 19.72 |
| 2026-08-13 12:00 | 18:05:14.78 | -71:36:54.9 | HIP 89002 | 22.14 |
| 2026-08-14 00:00 | 18:04:45.60 | -71:35:00.1 | HIP 89002 | 24.66 |
| 2026-08-14 12:00 | 18:04:16.80 | -71:33:04.4 | HIP 88678 | 26.46 |
| 2026-08-15 00:00 | 18:03:48.38 | -71:31:08.0 | HIP 88678 | 25.59 |
| 2026-08-15 12:00 | 18:03:20.34 | -71:29:10.8 | HIP 88678 | 25.02 |
| 2026-08-16 00:00 | 18:02:52.68 | -71:27:12.8 | HIP 88489 | 24.34 |
| 2026-08-16 12:00 | 18:02:25.40 | -71:25:14.1 | HIP 88489 | 23.11 |
| 2026-08-17 00:00 | 18:01:58.50 | -71:23:14.7 | HIP 88489 | 22.18 |
| 2026-08-17 12:00 | 18:01:31.98 | -71:21:14.6 | HIP 88489 | 21.59 |
| 2026-08-18 00:00 | 18:01:05.84 | -71:19:13.8 | HIP 88489 | 21.37 |
| 2026-08-18 12:00 | 18:00:40.09 | -71:17:12.4 | HIP 87898 | 20.02 |
| 2026-08-19 00:00 | 18:00:14.71 | -71:15:10.3 | HIP 87898 | 17.19 |