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
$$ M_a = (8.983 + 2.969\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
モデル定数
| 項目 | 値 |
|---|---|
| H0 | 8.983 |
| n | 2.969 |
| gf | 0.995 |
| gb | -0.726 |
| k | 0.800 |
| δ90 | 9.958 |
| 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 | +2.9322 | -2.158 |
| 2022-11-29 | 2023-04-18 | +1.2188 | -1.033 |
| 2023-06-12 | 2023-08-25 | +28.6584 | -11.897 |
| 2023-08-25 | 2023-12-28 | -3.8560 | +1.722 |
| 2023-12-28 | 2025-10-26 | +0.1869 | -0.600 |
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 | 19:54:49.64 | -64:47:28.4 | HIP 97564 | 32.68 |
| 2026-02-03 12:00 | 19:55:09.64 | -64:47:48.6 | HIP 97564 | 34.69 |
| 2026-02-04 00:00 | 19:55:29.57 | -64:48:09.6 | HIP 98117 | 34.50 |
| 2026-02-04 12:00 | 19:55:49.44 | -64:48:31.6 | HIP 98533 | 33.11 |
| 2026-02-05 00:00 | 19:56:09.23 | -64:48:54.6 | HIP 98533 | 31.01 |
| 2026-02-05 12:00 | 19:56:28.96 | -64:49:18.4 | HIP 98533 | 28.91 |
| 2026-02-06 00:00 | 19:56:48.62 | -64:49:43.3 | HIP 98533 | 26.84 |
| 2026-02-06 12:00 | 19:57:08.21 | -64:50:09.0 | HIP 98533 | 24.78 |
| 2026-02-07 00:00 | 19:57:27.72 | -64:50:35.7 | HIP 98533 | 22.74 |
| 2026-02-07 12:00 | 19:57:47.16 | -64:51:03.4 | HIP 98533 | 20.74 |
| 2026-02-08 00:00 | 19:58:06.52 | -64:51:32.0 | HIP 98533 | 18.76 |
| 2026-02-08 12:00 | 19:58:25.81 | -64:52:01.6 | HIP 98533 | 16.84 |
| 2026-02-09 00:00 | 19:58:45.02 | -64:52:32.1 | HIP 98533 | 14.98 |
| 2026-02-09 12:00 | 19:59:04.16 | -64:53:03.6 | HIP 98533 | 13.21 |
| 2026-02-10 00:00 | 19:59:23.21 | -64:53:36.0 | HIP 98533 | 11.56 |
| 2026-02-10 12:00 | 19:59:42.18 | -64:54:09.3 | HIP 98533 | 10.10 |
| 2026-02-11 00:00 | 20:00:01.07 | -64:54:43.6 | HIP 98533 | 8.92 |
| 2026-02-11 12:00 | 20:00:19.88 | -64:55:18.9 | HIP 98533 | 8.12 |
| 2026-02-12 00:00 | 20:00:38.60 | -64:55:55.2 | HIP 98533 | 7.84 |
| 2026-02-12 12:00 | 20:00:57.23 | -64:56:32.3 | HIP 98533 | 8.11 |
| 2026-02-13 00:00 | 20:01:15.78 | -64:57:10.5 | HIP 98533 | 8.88 |
| 2026-02-13 12:00 | 20:01:34.24 | -64:57:49.6 | HIP 98533 | 10.04 |
| 2026-02-14 00:00 | 20:01:52.61 | -64:58:29.6 | HIP 98533 | 11.47 |
| 2026-02-14 12:00 | 20:02:10.88 | -64:59:10.6 | HIP 98533 | 13.07 |
| 2026-02-15 00:00 | 20:02:29.07 | -64:59:52.6 | HIP 98533 | 14.79 |
| 2026-02-15 12:00 | 20:02:47.16 | -65:00:35.5 | HIP 98533 | 16.59 |
| 2026-02-16 00:00 | 20:03:05.15 | -65:01:19.4 | HIP 98741 | 16.13 |
| 2026-02-16 12:00 | 20:03:23.05 | -65:02:04.3 | HIP 98741 | 15.31 |
| 2026-02-17 00:00 | 20:03:40.85 | -65:02:50.1 | HIP 98741 | 14.71 |
| 2026-02-17 12:00 | 20:03:58.55 | -65:03:36.9 | HIP 98741 | 14.36 |
| 2026-02-18 00:00 | 20:04:16.15 | -65:04:24.6 | HIP 98741 | 14.26 |
| 2026-02-18 12:00 | 20:04:33.64 | -65:05:13.3 | HIP 98741 | 14.42 |
| 2026-02-19 00:00 | 20:04:51.03 | -65:06:02.9 | HIP 98741 | 14.84 |
| 2026-02-19 12:00 | 20:05:08.32 | -65:06:53.5 | HIP 98891 | 14.89 |
| 2026-02-20 00:00 | 20:05:25.50 | -65:07:45.1 | HIP 98891 | 14.33 |
| 2026-02-20 12:00 | 20:05:42.57 | -65:08:37.6 | HIP 98891 | 14.03 |
| 2026-02-21 00:00 | 20:05:59.54 | -65:09:31.1 | HIP 98891 | 13.98 |
| 2026-02-21 12:00 | 20:06:16.39 | -65:10:25.6 | HIP 98891 | 14.18 |
| 2026-02-22 00:00 | 20:06:33.13 | -65:11:20.9 | HIP 98891 | 14.64 |
| 2026-02-22 12:00 | 20:06:49.75 | -65:12:17.3 | HIP 98891 | 15.32 |
| 2026-02-23 00:00 | 20:07:06.27 | -65:13:14.6 | HIP 98891 | 16.19 |
| 2026-02-23 12:00 | 20:07:22.66 | -65:14:12.8 | HIP 98891 | 17.23 |
| 2026-02-24 00:00 | 20:07:38.94 | -65:15:12.0 | HIP 98891 | 18.40 |