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) |
|---|---|---|---|---|
| 2026-05-12 00:00 | 20:10:17.09 | -70:18:34.4 | HIP 99040 | 19.38 |
| 2026-05-12 12:00 | 20:09:55.82 | -70:20:59.5 | HIP 99040 | 17.43 |
| 2026-05-13 00:00 | 20:09:34.18 | -70:23:24.2 | HIP 99040 | 15.80 |
| 2026-05-13 12:00 | 20:09:12.16 | -70:25:48.5 | HIP 99040 | 14.58 |
| 2026-05-14 00:00 | 20:08:49.76 | -70:28:12.5 | HIP 99040 | 13.92 |
| 2026-05-14 12:00 | 20:08:26.99 | -70:30:36.1 | HIP 99040 | 13.88 |
| 2026-05-15 00:00 | 20:08:03.83 | -70:32:59.2 | HIP 99040 | 14.48 |
| 2026-05-15 12:00 | 20:07:40.30 | -70:35:21.9 | HIP 99162 | 13.60 |
| 2026-05-16 00:00 | 20:07:16.39 | -70:37:44.1 | HIP 99162 | 11.64 |
| 2026-05-16 12:00 | 20:06:52.10 | -70:40:05.8 | HIP 99162 | 10.27 |
| 2026-05-17 00:00 | 20:06:27.42 | -70:42:27.0 | HIP 99162 | 9.75 |
| 2026-05-17 12:00 | 20:06:02.37 | -70:44:47.7 | HIP 99162 | 10.22 |
| 2026-05-18 00:00 | 20:05:36.93 | -70:47:07.9 | HIP 99162 | 11.58 |
| 2026-05-18 12:00 | 20:05:11.12 | -70:49:27.4 | HIP 99162 | 13.56 |
| 2026-05-19 00:00 | 20:04:44.92 | -70:51:46.4 | HIP 99162 | 15.95 |
| 2026-05-19 12:00 | 20:04:18.34 | -70:54:04.8 | HIP 99162 | 18.58 |
| 2026-05-20 00:00 | 20:03:51.38 | -70:56:22.5 | HIP 99162 | 21.39 |
| 2026-05-20 12:00 | 20:03:24.04 | -70:58:39.6 | HIP 98414 | 21.04 |
| 2026-05-21 00:00 | 20:02:56.31 | -71:00:56.0 | HIP 98414 | 17.91 |
| 2026-05-21 12:00 | 20:02:28.21 | -71:03:11.7 | HIP 98414 | 14.81 |
| 2026-05-22 00:00 | 20:01:59.73 | -71:05:26.7 | HIP 98414 | 11.74 |
| 2026-05-22 12:00 | 20:01:30.87 | -71:07:41.0 | HIP 98414 | 8.77 |
| 2026-05-23 00:00 | 20:01:01.63 | -71:09:54.5 | HIP 98414 | 6.06 |
| 2026-05-23 12:00 | 20:00:32.01 | -71:12:07.2 | HIP 98414 | 4.16 |
| 2026-05-24 00:00 | 20:00:02.01 | -71:14:19.1 | HIP 98404 | 2.05 |
| 2026-05-24 12:00 | 19:59:31.64 | -71:16:30.2 | HIP 98404 | 3.45 |
| 2026-05-25 00:00 | 19:59:00.90 | -71:18:40.5 | HIP 98404 | 6.41 |
| 2026-05-25 12:00 | 19:58:29.77 | -71:20:49.9 | HIP 98404 | 9.59 |
| 2026-05-26 00:00 | 19:57:58.28 | -71:22:58.4 | HIP 98404 | 12.84 |
| 2026-05-26 12:00 | 19:57:26.41 | -71:25:06.0 | HIP 98404 | 16.11 |
| 2026-05-27 00:00 | 19:56:54.17 | -71:27:12.7 | HIP 97911 | 15.03 |
| 2026-05-27 12:00 | 19:56:21.56 | -71:29:18.5 | HIP 97911 | 13.12 |
| 2026-05-28 00:00 | 19:55:48.58 | -71:31:23.3 | HIP 97911 | 11.83 |
| 2026-05-28 12:00 | 19:55:15.24 | -71:33:27.2 | HIP 97911 | 11.39 |
| 2026-05-29 00:00 | 19:54:41.52 | -71:35:30.0 | HIP 97911 | 11.90 |
| 2026-05-29 12:00 | 19:54:07.45 | -71:37:31.8 | HIP 97911 | 13.25 |
| 2026-05-30 00:00 | 19:53:33.01 | -71:39:32.6 | HIP 97644 | 14.91 |
| 2026-05-30 12:00 | 19:52:58.20 | -71:41:32.3 | HIP 97644 | 11.58 |
| 2026-05-31 00:00 | 19:52:23.04 | -71:43:31.0 | HIP 97644 | 8.27 |
| 2026-05-31 12:00 | 19:51:47.52 | -71:45:28.5 | HIP 97644 | 5.08 |
| 2026-06-01 00:00 | 19:51:11.65 | -71:47:25.0 | HIP 97644 | 2.47 |
| 2026-06-01 12:00 | 19:50:35.42 | -71:49:20.3 | HIP 97644 | 3.12 |
| 2026-06-02 00:00 | 19:49:58.84 | -71:51:14.4 | HIP 97644 | 6.06 |