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) |
|---|---|---|---|---|
| 2026-05-12 00:00 | 12:15:11.19 | +70:06:58.5 | HIP 59746 | 5.03 |
| 2026-05-12 12:00 | 12:14:45.73 | +70:05:28.5 | HIP 59746 | 6.81 |
| 2026-05-13 00:00 | 12:14:20.53 | +70:03:57.4 | HIP 59746 | 9.02 |
| 2026-05-13 12:00 | 12:13:55.61 | +70:02:25.2 | HIP 59746 | 11.41 |
| 2026-05-14 00:00 | 12:13:30.96 | +70:00:52.0 | HIP 59746 | 13.89 |
| 2026-05-14 12:00 | 12:13:06.58 | +69:59:17.6 | HIP 59746 | 16.41 |
| 2026-05-15 00:00 | 12:12:42.48 | +69:57:42.3 | HIP 59248 | 18.00 |
| 2026-05-15 12:00 | 12:12:18.66 | +69:56:05.9 | HIP 59248 | 16.22 |
| 2026-05-16 00:00 | 12:11:55.12 | +69:54:28.6 | HIP 59248 | 14.71 |
| 2026-05-16 12:00 | 12:11:31.86 | +69:52:50.2 | HIP 59248 | 13.56 |
| 2026-05-17 00:00 | 12:11:08.87 | +69:51:10.9 | HIP 59248 | 12.86 |
| 2026-05-17 12:00 | 12:10:46.16 | +69:49:30.6 | HIP 59248 | 12.67 |
| 2026-05-18 00:00 | 12:10:23.74 | +69:47:49.4 | HIP 59248 | 13.02 |
| 2026-05-18 12:00 | 12:10:01.59 | +69:46:07.2 | HIP 59248 | 13.86 |
| 2026-05-19 00:00 | 12:09:39.73 | +69:44:24.1 | HIP 59248 | 15.11 |
| 2026-05-19 12:00 | 12:09:18.14 | +69:42:40.2 | HIP 59248 | 16.68 |
| 2026-05-20 00:00 | 12:08:56.84 | +69:40:55.3 | HIP 59248 | 18.47 |
| 2026-05-20 12:00 | 12:08:35.82 | +69:39:09.7 | HIP 59248 | 20.43 |
| 2026-05-21 00:00 | 12:08:15.08 | +69:37:23.1 | HIP 59248 | 22.52 |
| 2026-05-21 12:00 | 12:07:54.62 | +69:35:35.8 | HIP 59248 | 24.69 |
| 2026-05-22 00:00 | 12:07:34.45 | +69:33:47.6 | HIP 59248 | 26.93 |
| 2026-05-22 12:00 | 12:07:14.55 | +69:31:58.6 | HIP 59094 | 27.41 |
| 2026-05-23 00:00 | 12:06:54.93 | +69:30:08.9 | HIP 59094 | 25.60 |
| 2026-05-23 12:00 | 12:06:35.60 | +69:28:18.3 | HIP 59094 | 23.90 |
| 2026-05-24 00:00 | 12:06:16.54 | +69:26:27.1 | HIP 59094 | 22.34 |
| 2026-05-24 12:00 | 12:05:57.77 | +69:24:35.1 | HIP 59094 | 20.94 |
| 2026-05-25 00:00 | 12:05:39.27 | +69:22:42.3 | HIP 59094 | 19.75 |
| 2026-05-25 12:00 | 12:05:21.05 | +69:20:48.9 | HIP 59094 | 18.79 |
| 2026-05-26 00:00 | 12:05:03.11 | +69:18:54.8 | HIP 59094 | 18.10 |
| 2026-05-26 12:00 | 12:04:45.45 | +69:17:00.0 | HIP 58798 | 16.98 |
| 2026-05-27 00:00 | 12:04:28.06 | +69:15:04.5 | HIP 58798 | 14.64 |
| 2026-05-27 12:00 | 12:04:10.95 | +69:13:08.4 | HIP 58798 | 12.35 |
| 2026-05-28 00:00 | 12:03:54.12 | +69:11:11.7 | HIP 58798 | 10.13 |
| 2026-05-28 12:00 | 12:03:37.56 | +69:09:14.3 | HIP 58798 | 8.04 |
| 2026-05-29 00:00 | 12:03:21.27 | +69:07:16.3 | HIP 58798 | 6.21 |
| 2026-05-29 12:00 | 12:03:05.26 | +69:05:17.7 | HIP 58798 | 4.91 |
| 2026-05-30 00:00 | 12:02:49.52 | +69:03:18.6 | HIP 58798 | 4.63 |
| 2026-05-30 12:00 | 12:02:34.05 | +69:01:18.9 | HIP 58798 | 5.51 |
| 2026-05-31 00:00 | 12:02:18.86 | +68:59:18.6 | HIP 58798 | 7.13 |
| 2026-05-31 12:00 | 12:02:03.93 | +68:57:17.8 | HIP 58808 | 9.09 |
| 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 |