C/2020 R7 (ATLAS)
メタデータ
| 項目 | 値 |
|---|---|
| Designation | C/2020 R7 (ATLAS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2022-09-16T06:03:23.394240Z |
| Orbit solution date (soln_date, UTC) | 2024-08-11T00:12:15Z |
| Obs used | 1812 |
| NEO | - |
| M1 | 11.500 |
| K1 | 4.500 |
| PC | - |
| Discovery observation (MPC, UTC) | 2020-09-15T14:23:18.614400Z |
| Discovery magnitude (MPC) | 19.00 o |
| Discovery observatory (MPC) | T08 · ATLAS-MLO, Mauna Loa |
オスキュレーティング軌道要素
| 項目 | 値 |
|---|---|
| Epoch (epoch_cal, TDB) | 2023-02-02.0000000 |
| e | 1.00021432 |
| q (au) | 2.956013 |
| a (au) | -13792.591193 |
| i (deg) | 114.893954 |
| Ω (om, deg) | 268.282599 |
| ω (w, deg) | 347.841392 |
| M (ma, deg) | 0.000084 |
等級
散乱 + 全体線形
$$ M_a = (9.379 + 2.863\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
モデル定数
| 項目 | 値 |
|---|---|
| H0 | 9.379 |
| n | 2.863 |
| gf | 0.980 |
| gb | -1.000 |
| k | 0.999 |
| δ90 | 9.998 |
| 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 |
|---|---|---|---|
| 2019-12-03 | 2020-09-23 | +20.8410 | -18.349 |
| 2020-09-23 | 2021-08-10 | +4.7347 | -4.468 |
| 2021-08-10 | 2022-03-31 | -0.0032 | -1.068 |
| 2022-03-31 | 2022-09-15 | -12.9278 | +5.677 |
| 2022-09-19 | 2024-07-31 | +4.7248 | -2.800 |
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 | 11:58:34.88 | +64:50:10.0 | HIP 58650 | 20.33 |
| 2026-07-29 12:00 | 11:58:43.04 | +64:48:18.4 | HIP 58650 | 20.18 |
| 2026-07-30 00:00 | 11:58:51.31 | +64:46:27.4 | HIP 58650 | 20.23 |
| 2026-07-30 12:00 | 11:58:59.70 | +64:44:36.9 | HIP 58650 | 20.47 |
| 2026-07-31 00:00 | 11:59:08.20 | +64:42:46.9 | HIP 58650 | 20.88 |
| 2026-07-31 12:00 | 11:59:16.82 | +64:40:57.5 | HIP 58650 | 21.47 |
| 2026-08-01 00:00 | 11:59:25.54 | +64:39:08.6 | HIP 58650 | 22.21 |
| 2026-08-01 12:00 | 11:59:34.38 | +64:37:20.3 | HIP 58650 | 23.10 |
| 2026-08-02 00:00 | 11:59:43.33 | +64:35:32.6 | HIP 58650 | 24.11 |
| 2026-08-02 12:00 | 11:59:52.38 | +64:33:45.5 | HIP 58650 | 25.23 |
| 2026-08-03 00:00 | 12:00:01.54 | +64:31:58.9 | HIP 58650 | 26.44 |
| 2026-08-03 12:00 | 12:00:10.81 | +64:30:12.9 | HIP 58650 | 27.73 |
| 2026-08-04 00:00 | 12:00:20.18 | +64:28:27.4 | HIP 58650 | 29.10 |
| 2026-08-04 12:00 | 12:00:29.66 | +64:26:42.6 | HIP 58650 | 30.52 |
| 2026-08-05 00:00 | 12:00:39.24 | +64:24:58.4 | HIP 58860 | 30.54 |
| 2026-08-05 12:00 | 12:00:48.92 | +64:23:14.7 | HIP 58860 | 28.65 |
| 2026-08-06 00:00 | 12:00:58.71 | +64:21:31.7 | HIP 58860 | 26.78 |
| 2026-08-06 12:00 | 12:01:08.59 | +64:19:49.3 | HIP 58860 | 24.92 |
| 2026-08-07 00:00 | 12:01:18.57 | +64:18:07.5 | HIP 58860 | 23.08 |
| 2026-08-07 12:00 | 12:01:28.65 | +64:16:26.3 | HIP 58860 | 21.27 |
| 2026-08-08 00:00 | 12:01:38.83 | +64:14:45.7 | HIP 58860 | 19.49 |
| 2026-08-08 12:00 | 12:01:49.10 | +64:13:05.8 | HIP 58860 | 17.75 |
| 2026-08-09 00:00 | 12:01:59.47 | +64:11:26.5 | HIP 58860 | 16.07 |
| 2026-08-09 12:00 | 12:02:09.93 | +64:09:47.9 | HIP 58860 | 14.46 |
| 2026-08-10 00:00 | 12:02:20.49 | +64:08:09.9 | HIP 58860 | 12.95 |
| 2026-08-10 12:00 | 12:02:31.14 | +64:06:32.5 | HIP 58860 | 11.58 |
| 2026-08-11 00:00 | 12:02:41.87 | +64:04:55.8 | HIP 58860 | 10.40 |
| 2026-08-11 12:00 | 12:02:52.70 | +64:03:19.8 | HIP 58860 | 9.48 |
| 2026-08-12 00:00 | 12:03:03.62 | +64:01:44.5 | HIP 58860 | 8.91 |
| 2026-08-12 12:00 | 12:03:14.62 | +64:00:09.8 | HIP 58860 | 8.73 |
| 2026-08-13 00:00 | 12:03:25.71 | +63:58:35.8 | HIP 58860 | 8.99 |
| 2026-08-13 12:00 | 12:03:36.89 | +63:57:02.6 | HIP 58860 | 9.64 |
| 2026-08-14 00:00 | 12:03:48.15 | +63:55:30.0 | HIP 58860 | 10.61 |
| 2026-08-14 12:00 | 12:03:59.49 | +63:53:58.1 | HIP 58860 | 11.82 |
| 2026-08-15 00:00 | 12:04:10.91 | +63:52:26.9 | HIP 58860 | 13.20 |
| 2026-08-15 12:00 | 12:04:22.42 | +63:50:56.4 | HIP 58860 | 14.70 |
| 2026-08-16 00:00 | 12:04:34.00 | +63:49:26.6 | HIP 58860 | 16.29 |
| 2026-08-16 12:00 | 12:04:45.66 | +63:47:57.6 | HIP 58860 | 17.95 |
| 2026-08-17 00:00 | 12:04:57.40 | +63:46:29.2 | HIP 58860 | 19.65 |
| 2026-08-17 12:00 | 12:05:09.22 | +63:45:01.6 | HIP 58860 | 21.39 |
| 2026-08-18 00:00 | 12:05:21.11 | +63:43:34.8 | HIP 59190 | 21.86 |
| 2026-08-18 12:00 | 12:05:33.07 | +63:42:08.6 | HIP 59190 | 21.39 |
| 2026-08-19 00:00 | 12:05:45.11 | +63:40:43.2 | HIP 59190 | 21.08 |