メタデータ
| 項目 |
値 |
| Designation |
C/2020 F7 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-11-14T02:39:42.822720Z |
| Orbit solution date (soln_date, UTC) |
2023-12-28T19:42:30Z |
| Obs used |
608 |
| NEO |
- |
| M1 |
6.600 |
| K1 |
10.750 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2020-12-09.0000000 |
| e |
0.99310004 |
| q (au) |
5.331815 |
| a (au) |
772.731657 |
| i (deg) |
93.951702 |
| Ω (om, deg) |
321.886317 |
| ω (w, deg) |
227.985641 |
| M (ma, deg) |
359.984394 |
等級
散乱 + 全体線形
$$
M_a = (2.349 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
2.349 |
| n |
6.000 |
| gf |
0.977 |
| gb |
-0.693 |
| k |
1.000 |
| 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 |
| 2020-01-04 |
2021-11-11 |
+4.9500 |
-3.771 |
| 2021-11-14 |
2023-12-20 |
-12.9005 |
+9.601 |
log10 r = log10(太陽距離/AU)、Δ = 地球距離(AU)
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
22:59:52.84 |
-45:27:37.3 |
HIP 113490 |
8.92 |
| 2026-07-29 12:00 |
22:59:40.21 |
-45:28:35.8 |
HIP 113490 |
6.81 |
| 2026-07-30 00:00 |
22:59:27.51 |
-45:29:33.8 |
HIP 113490 |
4.98 |
| 2026-07-30 12:00 |
22:59:14.73 |
-45:30:31.3 |
HIP 113490 |
3.87 |
| 2026-07-31 00:00 |
22:59:01.88 |
-45:31:28.3 |
HIP 113490 |
4.11 |
| 2026-07-31 12:00 |
22:58:48.96 |
-45:32:24.8 |
HIP 113454 |
2.54 |
| 2026-08-01 00:00 |
22:58:35.97 |
-45:33:20.8 |
HIP 113454 |
2.18 |
| 2026-08-01 12:00 |
22:58:22.91 |
-45:34:16.2 |
HIP 113454 |
3.89 |
| 2026-08-02 00:00 |
22:58:09.78 |
-45:35:11.1 |
HIP 113454 |
6.15 |
| 2026-08-02 12:00 |
22:57:56.58 |
-45:36:05.5 |
HIP 113454 |
8.53 |
| 2026-08-03 00:00 |
22:57:43.32 |
-45:36:59.3 |
HIP 113454 |
10.96 |
| 2026-08-03 12:00 |
22:57:29.99 |
-45:37:52.6 |
HIP 113454 |
13.41 |
| 2026-08-04 00:00 |
22:57:16.60 |
-45:38:45.3 |
HIP 113454 |
15.88 |
| 2026-08-04 12:00 |
22:57:03.14 |
-45:39:37.4 |
HIP 113454 |
18.37 |
| 2026-08-05 00:00 |
22:56:49.62 |
-45:40:28.9 |
HIP 113454 |
20.86 |
| 2026-08-05 12:00 |
22:56:36.04 |
-45:41:19.9 |
HIP 113425 |
22.89 |
| 2026-08-06 00:00 |
22:56:22.39 |
-45:42:10.2 |
HIP 113425 |
24.32 |
| 2026-08-06 12:00 |
22:56:08.69 |
-45:43:00.0 |
HIP 113100 |
22.16 |
| 2026-08-07 00:00 |
22:55:54.93 |
-45:43:49.0 |
HIP 113100 |
19.66 |
| 2026-08-07 12:00 |
22:55:41.11 |
-45:44:37.5 |
HIP 113100 |
17.16 |
| 2026-08-08 00:00 |
22:55:27.23 |
-45:45:25.4 |
HIP 113100 |
14.68 |
| 2026-08-08 12:00 |
22:55:13.30 |
-45:46:12.6 |
HIP 113100 |
12.23 |
| 2026-08-09 00:00 |
22:54:59.32 |
-45:46:59.1 |
HIP 113100 |
9.82 |
| 2026-08-09 12:00 |
22:54:45.28 |
-45:47:45.0 |
HIP 113100 |
7.53 |
| 2026-08-10 00:00 |
22:54:31.19 |
-45:48:30.2 |
HIP 113100 |
5.48 |
| 2026-08-10 12:00 |
22:54:17.05 |
-45:49:14.8 |
HIP 113100 |
4.07 |
| 2026-08-11 00:00 |
22:54:02.86 |
-45:49:58.6 |
HIP 113057 |
4.00 |
| 2026-08-11 12:00 |
22:53:48.62 |
-45:50:41.8 |
HIP 113057 |
3.18 |
| 2026-08-12 00:00 |
22:53:34.34 |
-45:51:24.3 |
HIP 113057 |
4.18 |
| 2026-08-12 12:00 |
22:53:20.01 |
-45:52:06.0 |
HIP 113057 |
6.18 |
| 2026-08-13 00:00 |
22:53:05.63 |
-45:52:47.1 |
HIP 112954 |
5.34 |
| 2026-08-13 12:00 |
22:52:51.21 |
-45:53:27.4 |
HIP 112954 |
2.89 |
| 2026-08-14 00:00 |
22:52:36.75 |
-45:54:07.0 |
HIP 112954 |
1.29 |
| 2026-08-14 12:00 |
22:52:22.25 |
-45:54:45.9 |
HIP 112954 |
2.91 |
| 2026-08-15 00:00 |
22:52:07.71 |
-45:55:24.0 |
HIP 112939 |
5.22 |
| 2026-08-15 12:00 |
22:51:53.14 |
-45:56:01.4 |
HIP 112939 |
6.75 |
| 2026-08-16 00:00 |
22:51:38.52 |
-45:56:38.0 |
HIP 112939 |
8.80 |
| 2026-08-16 12:00 |
22:51:23.88 |
-45:57:13.8 |
HIP 112939 |
11.10 |
| 2026-08-17 00:00 |
22:51:09.19 |
-45:57:48.9 |
HIP 112939 |
13.53 |
| 2026-08-17 12:00 |
22:50:54.48 |
-45:58:23.2 |
HIP 112939 |
16.02 |
| 2026-08-18 00:00 |
22:50:39.73 |
-45:58:56.7 |
HIP 112939 |
18.55 |
| 2026-08-18 12:00 |
22:50:24.96 |
-45:59:29.4 |
HIP 112613 |
20.52 |
| 2026-08-19 00:00 |
22:50:10.16 |
-46:00:01.4 |
HIP 112613 |
17.89 |