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) |
|---|---|---|---|---|
| 2026-06-01 00:00 | 12:01:49.28 | +68:55:16.4 | HIP 58808 | 10.37 |
| 2026-06-01 12:00 | 12:01:34.89 | +68:53:14.6 | HIP 58808 | 11.98 |
| 2026-06-02 00:00 | 12:01:20.77 | +68:51:12.2 | HIP 58808 | 13.81 |
| 2026-06-02 12:00 | 12:01:06.92 | +68:49:09.4 | HIP 58808 | 15.78 |
| 2026-06-03 00:00 | 12:00:53.33 | +68:47:06.1 | HIP 58808 | 17.84 |
| 2026-06-03 12:00 | 12:00:40.01 | +68:45:02.3 | HIP 58808 | 19.97 |
| 2026-06-04 00:00 | 12:00:26.95 | +68:42:58.0 | HIP 58808 | 22.13 |
| 2026-06-04 12:00 | 12:00:14.16 | +68:40:53.3 | HIP 58808 | 24.33 |
| 2026-06-05 00:00 | 12:00:01.62 | +68:38:48.2 | HIP 58808 | 26.54 |
| 2026-06-05 12:00 | 11:59:49.35 | +68:36:42.7 | HIP 58808 | 28.77 |
| 2026-06-06 00:00 | 11:59:37.34 | +68:34:36.8 | HIP 58215 | 26.76 |
| 2026-06-06 12:00 | 11:59:25.59 | +68:32:30.5 | HIP 58215 | 24.49 |
| 2026-06-07 00:00 | 11:59:14.10 | +68:30:23.8 | HIP 58215 | 22.25 |
| 2026-06-07 12:00 | 11:59:02.86 | +68:28:16.7 | HIP 58215 | 20.06 |
| 2026-06-08 00:00 | 11:58:51.88 | +68:26:09.3 | HIP 58215 | 17.91 |
| 2026-06-08 12:00 | 11:58:41.16 | +68:24:01.5 | HIP 58215 | 15.83 |
| 2026-06-09 00:00 | 11:58:30.69 | +68:21:53.4 | HIP 58215 | 13.86 |
| 2026-06-09 12:00 | 11:58:20.47 | +68:19:45.0 | HIP 58215 | 12.04 |
| 2026-06-10 00:00 | 11:58:10.50 | +68:17:36.3 | HIP 58215 | 10.44 |
| 2026-06-10 12:00 | 11:58:00.79 | +68:15:27.3 | HIP 58215 | 9.19 |
| 2026-06-11 00:00 | 11:57:51.32 | +68:13:18.0 | HIP 58215 | 8.43 |
| 2026-06-11 12:00 | 11:57:42.11 | +68:11:08.4 | HIP 58215 | 8.29 |
| 2026-06-12 00:00 | 11:57:33.14 | +68:08:58.6 | HIP 58215 | 8.81 |
| 2026-06-12 12:00 | 11:57:24.42 | +68:06:48.5 | HIP 58215 | 9.88 |
| 2026-06-13 00:00 | 11:57:15.94 | +68:04:38.2 | HIP 58215 | 11.33 |
| 2026-06-13 12:00 | 11:57:07.71 | +68:02:27.6 | HIP 58215 | 13.05 |
| 2026-06-14 00:00 | 11:56:59.72 | +68:00:16.9 | HIP 58358 | 12.88 |
| 2026-06-14 12:00 | 11:56:51.97 | +67:58:05.9 | HIP 58358 | 11.36 |
| 2026-06-15 00:00 | 11:56:44.47 | +67:55:54.8 | HIP 58358 | 10.13 |
| 2026-06-15 12:00 | 11:56:37.20 | +67:53:43.4 | HIP 58358 | 9.29 |
| 2026-06-16 00:00 | 11:56:30.17 | +67:51:32.0 | HIP 58358 | 8.95 |
| 2026-06-16 12:00 | 11:56:23.37 | +67:49:20.3 | HIP 58358 | 9.17 |
| 2026-06-17 00:00 | 11:56:16.81 | +67:47:08.5 | HIP 58358 | 9.91 |
| 2026-06-17 12:00 | 11:56:10.49 | +67:44:56.6 | HIP 58358 | 11.05 |
| 2026-06-18 00:00 | 11:56:04.40 | +67:42:44.6 | HIP 58358 | 12.50 |
| 2026-06-18 12:00 | 11:55:58.53 | +67:40:32.5 | HIP 58358 | 14.14 |
| 2026-06-19 00:00 | 11:55:52.90 | +67:38:20.3 | HIP 58358 | 15.93 |
| 2026-06-19 12:00 | 11:55:47.49 | +67:36:08.0 | HIP 58358 | 17.81 |
| 2026-06-20 00:00 | 11:55:42.31 | +67:33:55.6 | HIP 58160 | 18.03 |
| 2026-06-20 12:00 | 11:55:37.36 | +67:31:43.2 | HIP 58160 | 15.83 |
| 2026-06-21 00:00 | 11:55:32.62 | +67:29:30.7 | HIP 58160 | 13.64 |
| 2026-06-21 12:00 | 11:55:28.11 | +67:27:18.2 | HIP 58160 | 11.47 |
| 2026-06-22 00:00 | 11:55:23.82 | +67:25:05.7 | HIP 58160 | 9.34 |