メタデータ
| 項目 |
値 |
| Designation |
C/2018 EF9 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2018-05-23T03:04:52.170240Z |
| Orbit solution date (soln_date, UTC) |
2023-02-13T23:12:43Z |
| Obs used |
191 |
| NEO |
- |
| M1 |
8.600 |
| K1 |
45.250 |
| PC |
0.030 |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2018-04-18.0000000 |
| e |
0.99757417 |
| q (au) |
1.556633 |
| a (au) |
641.691299 |
| i (deg) |
84.694453 |
| Ω (om, deg) |
172.578066 |
| ω (w, deg) |
72.616575 |
| M (ma, deg) |
359.997870 |
等級
散乱 + 全体線形
$$
M_a = (8.870 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
8.870 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.997 |
| 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
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
01:20:45.84 |
-38:09:07.7 |
HIP 6304 |
22.63 |
| 2026-07-29 12:00 |
01:20:44.49 |
-38:10:17.7 |
HIP 6304 |
21.51 |
| 2026-07-30 00:00 |
01:20:43.09 |
-38:11:27.8 |
HIP 6304 |
20.39 |
| 2026-07-30 12:00 |
01:20:41.64 |
-38:12:38.0 |
HIP 6304 |
19.29 |
| 2026-07-31 00:00 |
01:20:40.13 |
-38:13:48.2 |
HIP 6304 |
18.20 |
| 2026-07-31 12:00 |
01:20:38.56 |
-38:14:58.5 |
HIP 6304 |
17.13 |
| 2026-08-01 00:00 |
01:20:36.94 |
-38:16:08.8 |
HIP 6304 |
16.08 |
| 2026-08-01 12:00 |
01:20:35.26 |
-38:17:19.2 |
HIP 6304 |
15.06 |
| 2026-08-02 00:00 |
01:20:33.53 |
-38:18:29.6 |
HIP 6304 |
14.07 |
| 2026-08-02 12:00 |
01:20:31.75 |
-38:19:40.0 |
HIP 6304 |
13.13 |
| 2026-08-03 00:00 |
01:20:29.91 |
-38:20:50.5 |
HIP 6304 |
12.24 |
| 2026-08-03 12:00 |
01:20:28.02 |
-38:22:01.0 |
HIP 6304 |
11.42 |
| 2026-08-04 00:00 |
01:20:26.07 |
-38:23:11.5 |
HIP 6304 |
10.68 |
| 2026-08-04 12:00 |
01:20:24.06 |
-38:24:22.0 |
HIP 6304 |
10.05 |
| 2026-08-05 00:00 |
01:20:22.01 |
-38:25:32.5 |
HIP 6304 |
9.55 |
| 2026-08-05 12:00 |
01:20:19.90 |
-38:26:43.1 |
HIP 6304 |
9.20 |
| 2026-08-06 00:00 |
01:20:17.73 |
-38:27:53.6 |
HIP 6304 |
9.01 |
| 2026-08-06 12:00 |
01:20:15.51 |
-38:29:04.1 |
HIP 6304 |
9.01 |
| 2026-08-07 00:00 |
01:20:13.24 |
-38:30:14.6 |
HIP 6304 |
9.20 |
| 2026-08-07 12:00 |
01:20:10.91 |
-38:31:25.1 |
HIP 6304 |
9.55 |
| 2026-08-08 00:00 |
01:20:08.53 |
-38:32:35.6 |
HIP 6304 |
10.06 |
| 2026-08-08 12:00 |
01:20:06.09 |
-38:33:46.0 |
HIP 6304 |
10.71 |
| 2026-08-09 00:00 |
01:20:03.60 |
-38:34:56.5 |
HIP 6304 |
11.47 |
| 2026-08-09 12:00 |
01:20:01.06 |
-38:36:06.8 |
HIP 6304 |
12.33 |
| 2026-08-10 00:00 |
01:19:58.46 |
-38:37:17.1 |
HIP 6304 |
13.26 |
| 2026-08-10 12:00 |
01:19:55.81 |
-38:38:27.4 |
HIP 6304 |
14.25 |
| 2026-08-11 00:00 |
01:19:53.11 |
-38:39:37.6 |
HIP 6304 |
15.30 |
| 2026-08-11 12:00 |
01:19:50.35 |
-38:40:47.8 |
HIP 6304 |
16.38 |
| 2026-08-12 00:00 |
01:19:47.54 |
-38:41:57.9 |
HIP 6201 |
16.03 |
| 2026-08-12 12:00 |
01:19:44.68 |
-38:43:07.9 |
HIP 6201 |
14.78 |
| 2026-08-13 00:00 |
01:19:41.77 |
-38:44:17.8 |
HIP 6201 |
13.54 |
| 2026-08-13 12:00 |
01:19:38.80 |
-38:45:27.7 |
HIP 6201 |
12.30 |
| 2026-08-14 00:00 |
01:19:35.78 |
-38:46:37.4 |
HIP 6201 |
11.09 |
| 2026-08-14 12:00 |
01:19:32.71 |
-38:47:47.1 |
HIP 6201 |
9.90 |
| 2026-08-15 00:00 |
01:19:29.59 |
-38:48:56.7 |
HIP 6201 |
8.74 |
| 2026-08-15 12:00 |
01:19:26.42 |
-38:50:06.1 |
HIP 6201 |
7.63 |
| 2026-08-16 00:00 |
01:19:23.19 |
-38:51:15.5 |
HIP 6201 |
6.61 |
| 2026-08-16 12:00 |
01:19:19.92 |
-38:52:24.7 |
HIP 6201 |
5.71 |
| 2026-08-17 00:00 |
01:19:16.59 |
-38:53:33.8 |
HIP 6201 |
5.01 |
| 2026-08-17 12:00 |
01:19:13.21 |
-38:54:42.7 |
HIP 6201 |
4.60 |
| 2026-08-18 00:00 |
01:19:09.79 |
-38:55:51.6 |
HIP 6201 |
4.56 |
| 2026-08-18 12:00 |
01:19:06.31 |
-38:57:00.3 |
HIP 6201 |
4.90 |
| 2026-08-19 00:00 |
01:19:02.79 |
-38:58:08.8 |
HIP 6201 |
5.56 |