メタデータ
| 項目 |
値 |
| Designation |
C/2021 G1 (Leonard) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-07-22T06:47:31.761600Z |
| Orbit solution date (soln_date, UTC) |
2025-01-14T17:42:12Z |
| Obs used |
54 |
| NEO |
- |
| M1 |
13.700 |
| K1 |
10.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-04-11T07:50:24.892800Z |
| Discovery magnitude (MPC) |
21.72 G |
| Discovery observatory (MPC) |
G96 · Mt. Lemmon Survey |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2021-04-21.0000000 |
| e |
0.95490157 |
| q (au) |
3.423704 |
| a (au) |
75.916250 |
| i (deg) |
131.566251 |
| Ω (om, deg) |
270.695657 |
| ω (w, deg) |
107.498712 |
| M (ma, deg) |
359.862493 |
等級
散乱 + 全体線形
$$
M_a = (19.995 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
19.995 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.800 |
| 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) |
| 2026-03-26 00:00 |
03:47:09.07 |
-12:47:15.2 |
HIP 17787 |
36.33 |
| 2026-03-26 12:00 |
03:47:13.21 |
-12:46:23.5 |
HIP 17787 |
36.57 |
| 2026-03-27 00:00 |
03:47:17.41 |
-12:45:32.1 |
HIP 17787 |
36.85 |
| 2026-03-27 12:00 |
03:47:21.67 |
-12:44:40.9 |
HIP 17787 |
37.17 |
| 2026-03-28 00:00 |
03:47:25.97 |
-12:43:50.0 |
HIP 17787 |
37.52 |
| 2026-03-28 12:00 |
03:47:30.34 |
-12:42:59.4 |
HIP 17787 |
37.91 |
| 2026-03-29 00:00 |
03:47:34.75 |
-12:42:09.0 |
HIP 17787 |
38.33 |
| 2026-03-29 12:00 |
03:47:39.22 |
-12:41:18.9 |
HIP 17787 |
38.79 |
| 2026-03-30 00:00 |
03:47:43.75 |
-12:40:29.1 |
HIP 17787 |
39.28 |
| 2026-03-30 12:00 |
03:47:48.32 |
-12:39:39.6 |
HIP 17787 |
39.80 |
| 2026-03-31 00:00 |
03:47:52.95 |
-12:38:50.4 |
HIP 17787 |
40.36 |
| 2026-03-31 12:00 |
03:47:57.63 |
-12:38:01.5 |
HIP 17787 |
40.96 |
| 2026-04-01 00:00 |
03:48:02.36 |
-12:37:12.9 |
HIP 17787 |
41.58 |
| 2026-04-01 12:00 |
03:48:07.13 |
-12:36:24.6 |
HIP 17593 |
41.93 |
| 2026-04-02 00:00 |
03:48:11.96 |
-12:35:36.6 |
HIP 17593 |
42.19 |
| 2026-04-02 12:00 |
03:48:16.84 |
-12:34:48.9 |
HIP 17593 |
42.51 |
| 2026-04-03 00:00 |
03:48:21.77 |
-12:34:01.5 |
HIP 17593 |
42.88 |
| 2026-04-03 12:00 |
03:48:26.75 |
-12:33:14.4 |
HIP 17593 |
43.32 |
| 2026-04-04 00:00 |
03:48:31.77 |
-12:32:27.6 |
HIP 17593 |
43.81 |
| 2026-04-04 12:00 |
03:48:36.85 |
-12:31:41.2 |
HIP 17977 |
43.08 |
| 2026-04-05 00:00 |
03:48:41.97 |
-12:30:55.1 |
HIP 17977 |
41.68 |
| 2026-04-05 12:00 |
03:48:47.13 |
-12:30:09.3 |
HIP 17977 |
40.27 |
| 2026-04-06 00:00 |
03:48:52.35 |
-12:29:23.9 |
HIP 17977 |
38.87 |
| 2026-04-06 12:00 |
03:48:57.61 |
-12:28:38.8 |
HIP 17977 |
37.47 |
| 2026-04-07 00:00 |
03:49:02.91 |
-12:27:54.0 |
HIP 17977 |
36.07 |
| 2026-04-07 12:00 |
03:49:08.26 |
-12:27:09.6 |
HIP 17977 |
34.68 |
| 2026-04-08 00:00 |
03:49:13.65 |
-12:26:25.5 |
HIP 17977 |
33.30 |
| 2026-04-08 12:00 |
03:49:19.09 |
-12:25:41.8 |
HIP 17977 |
31.93 |
| 2026-04-09 00:00 |
03:49:24.57 |
-12:24:58.4 |
HIP 17977 |
30.57 |
| 2026-04-09 12:00 |
03:49:30.10 |
-12:24:15.4 |
HIP 17977 |
29.22 |
| 2026-04-10 00:00 |
03:49:35.67 |
-12:23:32.8 |
HIP 17977 |
27.90 |
| 2026-04-10 12:00 |
03:49:41.27 |
-12:22:50.5 |
HIP 17977 |
26.59 |
| 2026-04-11 00:00 |
03:49:46.93 |
-12:22:08.6 |
HIP 17977 |
25.32 |
| 2026-04-11 12:00 |
03:49:52.62 |
-12:21:27.0 |
HIP 17977 |
24.07 |
| 2026-04-12 00:00 |
03:49:58.35 |
-12:20:45.8 |
HIP 17977 |
22.87 |
| 2026-04-12 12:00 |
03:50:04.12 |
-12:20:05.0 |
HIP 17977 |
21.72 |
| 2026-04-13 00:00 |
03:50:09.94 |
-12:19:24.6 |
HIP 17977 |
20.62 |
| 2026-04-13 12:00 |
03:50:15.79 |
-12:18:44.6 |
HIP 17977 |
19.59 |
| 2026-04-14 00:00 |
03:50:21.68 |
-12:18:05.0 |
HIP 17977 |
18.64 |
| 2026-04-14 12:00 |
03:50:27.61 |
-12:17:25.7 |
HIP 17977 |
17.79 |
| 2026-04-15 00:00 |
03:50:33.57 |
-12:16:46.9 |
HIP 17977 |
17.05 |
| 2026-04-15 12:00 |
03:50:39.58 |
-12:16:08.4 |
HIP 17977 |
16.44 |
| 2026-04-16 00:00 |
03:50:45.62 |
-12:15:30.4 |
HIP 17977 |
15.98 |