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) |
|---|---|---|---|---|
| 2026-09-20 00:00 | 12:20:25.61 | +62:38:04.2 | HIP 60108 | 10.46 |
| 2026-09-20 12:00 | 12:20:40.46 | +62:37:34.7 | HIP 60108 | 11.04 |
| 2026-09-21 00:00 | 12:20:55.32 | +62:37:06.2 | HIP 60108 | 11.86 |
| 2026-09-21 12:00 | 12:21:10.20 | +62:36:38.7 | HIP 60108 | 12.89 |
| 2026-09-22 00:00 | 12:21:25.09 | +62:36:12.1 | HIP 60108 | 14.08 |
| 2026-09-22 12:00 | 12:21:39.99 | +62:35:46.5 | HIP 60108 | 15.40 |
| 2026-09-23 00:00 | 12:21:54.90 | +62:35:21.9 | HIP 60108 | 16.80 |
| 2026-09-23 12:00 | 12:22:09.82 | +62:34:58.2 | HIP 60108 | 18.27 |
| 2026-09-24 00:00 | 12:22:24.75 | +62:34:35.6 | HIP 60108 | 19.80 |
| 2026-09-24 12:00 | 12:22:39.68 | +62:34:13.9 | HIP 60108 | 21.37 |
| 2026-09-25 00:00 | 12:22:54.63 | +62:33:53.2 | HIP 60108 | 22.97 |
| 2026-09-25 12:00 | 12:23:09.58 | +62:33:33.5 | HIP 60108 | 24.60 |
| 2026-09-26 00:00 | 12:23:24.54 | +62:33:14.8 | HIP 60108 | 26.25 |
| 2026-09-26 12:00 | 12:23:39.50 | +62:32:57.1 | HIP 60652 | 26.95 |
| 2026-09-27 00:00 | 12:23:54.47 | +62:32:40.3 | HIP 60652 | 25.76 |
| 2026-09-27 12:00 | 12:24:09.44 | +62:32:24.6 | HIP 60652 | 24.64 |
| 2026-09-28 00:00 | 12:24:24.41 | +62:32:09.9 | HIP 60652 | 23.62 |
| 2026-09-28 12:00 | 12:24:39.39 | +62:31:56.1 | HIP 60652 | 22.70 |
| 2026-09-29 00:00 | 12:24:54.37 | +62:31:43.4 | HIP 60652 | 21.90 |
| 2026-09-29 12:00 | 12:25:09.35 | +62:31:31.6 | HIP 60652 | 21.23 |
| 2026-09-30 00:00 | 12:25:24.32 | +62:31:20.9 | HIP 60652 | 20.70 |
| 2026-09-30 12:00 | 12:25:39.30 | +62:31:11.2 | HIP 60652 | 20.33 |
| 2026-10-01 00:00 | 12:25:54.28 | +62:31:02.4 | HIP 60652 | 20.11 |
| 2026-10-01 12:00 | 12:26:09.25 | +62:30:54.7 | HIP 60652 | 20.07 |
| 2026-10-02 00:00 | 12:26:24.22 | +62:30:48.0 | HIP 60652 | 20.19 |
| 2026-10-02 12:00 | 12:26:39.19 | +62:30:42.4 | HIP 60652 | 20.48 |
| 2026-10-03 00:00 | 12:26:54.15 | +62:30:37.7 | HIP 60652 | 20.92 |
| 2026-10-03 12:00 | 12:27:09.11 | +62:30:34.1 | HIP 60652 | 21.51 |
| 2026-10-04 00:00 | 12:27:24.06 | +62:30:31.5 | HIP 60652 | 22.24 |
| 2026-10-04 12:00 | 12:27:39.00 | +62:30:29.9 | HIP 60652 | 23.09 |
| 2026-10-05 00:00 | 12:27:53.94 | +62:30:29.3 | HIP 60652 | 24.04 |
| 2026-10-05 12:00 | 12:28:08.86 | +62:30:29.8 | HIP 61117 | 23.61 |
| 2026-10-06 00:00 | 12:28:23.78 | +62:30:31.4 | HIP 61117 | 21.90 |
| 2026-10-06 12:00 | 12:28:38.68 | +62:30:33.9 | HIP 61117 | 20.18 |
| 2026-10-07 00:00 | 12:28:53.58 | +62:30:37.5 | HIP 61117 | 18.48 |
| 2026-10-07 12:00 | 12:29:08.46 | +62:30:42.2 | HIP 61117 | 16.77 |
| 2026-10-08 00:00 | 12:29:23.32 | +62:30:47.9 | HIP 61117 | 15.08 |
| 2026-10-08 12:00 | 12:29:38.18 | +62:30:54.6 | HIP 61117 | 13.39 |
| 2026-10-09 00:00 | 12:29:53.01 | +62:31:02.4 | HIP 61117 | 11.72 |
| 2026-10-09 12:00 | 12:30:07.83 | +62:31:11.2 | HIP 61117 | 10.07 |
| 2026-10-10 00:00 | 12:30:22.63 | +62:31:21.1 | HIP 61117 | 8.45 |
| 2026-10-10 12:00 | 12:30:37.42 | +62:31:32.1 | HIP 61117 | 6.90 |
| 2026-10-11 00:00 | 12:30:52.18 | +62:31:44.1 | HIP 61117 | 5.45 |