メタデータ
| 項目 |
値 |
| Designation |
C/2021 U4 (Leonard) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-12-21T23:21:30.078720Z |
| Orbit solution date (soln_date, UTC) |
2025-01-14T17:42:12Z |
| Obs used |
37 |
| NEO |
- |
| M1 |
18.800 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-10-31T07:11:48.940800Z |
| Discovery magnitude (MPC) |
19.87 G |
| Discovery observatory (MPC) |
G96 · University of Arizona Mt. Lemmon Survey |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2021-10-27.0000000 |
| e |
0.95934634 |
| q (au) |
1.787292 |
| a (au) |
43.963864 |
| i (deg) |
152.875238 |
| Ω (om, deg) |
241.798913 |
| ω (w, deg) |
237.287717 |
| M (ma, deg) |
359.810748 |
等級
散乱 + 全体線形
$$
M_a = (19.361 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
19.361 |
| n |
2.000 |
| gf |
0.977 |
| gb |
-0.500 |
| k |
0.800 |
| δ90 |
5.683 |
| 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) |
| 2026-09-20 00:00 |
14:49:41.32 |
-08:09:18.9 |
HIP 72606 |
15.61 |
| 2026-09-20 12:00 |
14:49:46.03 |
-08:09:44.9 |
HIP 72606 |
14.38 |
| 2026-09-21 00:00 |
14:49:50.77 |
-08:10:11.0 |
HIP 72606 |
13.13 |
| 2026-09-21 12:00 |
14:49:55.56 |
-08:10:37.1 |
HIP 72606 |
11.87 |
| 2026-09-22 00:00 |
14:50:00.39 |
-08:11:03.4 |
HIP 72606 |
10.61 |
| 2026-09-22 12:00 |
14:50:05.27 |
-08:11:29.7 |
HIP 72606 |
9.34 |
| 2026-09-23 00:00 |
14:50:10.19 |
-08:11:56.1 |
HIP 72606 |
8.06 |
| 2026-09-23 12:00 |
14:50:15.15 |
-08:12:22.6 |
HIP 72606 |
6.77 |
| 2026-09-24 00:00 |
14:50:20.15 |
-08:12:49.1 |
HIP 72606 |
5.48 |
| 2026-09-24 12:00 |
14:50:25.19 |
-08:13:15.8 |
HIP 72606 |
4.20 |
| 2026-09-25 00:00 |
14:50:30.27 |
-08:13:42.5 |
HIP 72606 |
2.95 |
| 2026-09-25 12:00 |
14:50:35.40 |
-08:14:09.2 |
HIP 72606 |
1.81 |
| 2026-09-26 00:00 |
14:50:40.56 |
-08:14:36.0 |
HIP 72606 |
1.21 |
| 2026-09-26 12:00 |
14:50:45.77 |
-08:15:02.9 |
HIP 72606 |
1.82 |
| 2026-09-27 00:00 |
14:50:51.01 |
-08:15:29.8 |
HIP 72606 |
2.99 |
| 2026-09-27 12:00 |
14:50:56.29 |
-08:15:56.8 |
HIP 72606 |
4.29 |
| 2026-09-28 00:00 |
14:51:01.61 |
-08:16:23.9 |
HIP 72606 |
5.64 |
| 2026-09-28 12:00 |
14:51:06.97 |
-08:16:51.0 |
HIP 72606 |
7.01 |
| 2026-09-29 00:00 |
14:51:12.37 |
-08:17:18.1 |
HIP 72606 |
8.40 |
| 2026-09-29 12:00 |
14:51:17.80 |
-08:17:45.3 |
HIP 72606 |
9.81 |
| 2026-09-30 00:00 |
14:51:23.27 |
-08:18:12.6 |
HIP 72606 |
11.23 |
| 2026-09-30 12:00 |
14:51:28.78 |
-08:18:39.8 |
HIP 72606 |
12.65 |
| 2026-10-01 00:00 |
14:51:34.32 |
-08:19:07.2 |
HIP 72606 |
14.09 |
| 2026-10-01 12:00 |
14:51:39.90 |
-08:19:34.5 |
HIP 72606 |
15.54 |
| 2026-10-02 00:00 |
14:51:45.52 |
-08:20:01.9 |
HIP 72606 |
17.00 |
| 2026-10-02 12:00 |
14:51:51.17 |
-08:20:29.3 |
HIP 72606 |
18.46 |
| 2026-10-03 00:00 |
14:51:56.85 |
-08:20:56.8 |
HIP 72606 |
19.94 |
| 2026-10-03 12:00 |
14:52:02.57 |
-08:21:24.3 |
HIP 72606 |
21.42 |
| 2026-10-04 00:00 |
14:52:08.33 |
-08:21:51.8 |
HIP 72808 |
22.82 |
| 2026-10-04 12:00 |
14:52:14.11 |
-08:22:19.3 |
HIP 72808 |
21.74 |
| 2026-10-05 00:00 |
14:52:19.93 |
-08:22:46.9 |
HIP 72808 |
20.71 |
| 2026-10-05 12:00 |
14:52:25.78 |
-08:23:14.4 |
HIP 72808 |
19.74 |
| 2026-10-06 00:00 |
14:52:31.67 |
-08:23:42.0 |
HIP 72808 |
18.84 |
| 2026-10-06 12:00 |
14:52:37.59 |
-08:24:09.6 |
HIP 72808 |
18.02 |
| 2026-10-07 00:00 |
14:52:43.53 |
-08:24:37.2 |
HIP 72808 |
17.30 |
| 2026-10-07 12:00 |
14:52:49.51 |
-08:25:04.8 |
HIP 72808 |
16.69 |
| 2026-10-08 00:00 |
14:52:55.52 |
-08:25:32.4 |
HIP 72808 |
16.21 |
| 2026-10-08 12:00 |
14:53:01.56 |
-08:26:00.0 |
HIP 72808 |
15.86 |
| 2026-10-09 00:00 |
14:53:07.63 |
-08:26:27.6 |
HIP 72808 |
15.67 |
| 2026-10-09 12:00 |
14:53:13.72 |
-08:26:55.2 |
HIP 72808 |
15.63 |
| 2026-10-10 00:00 |
14:53:19.85 |
-08:27:22.7 |
HIP 72808 |
15.76 |
| 2026-10-10 12:00 |
14:53:26.00 |
-08:27:50.3 |
HIP 72808 |
16.04 |
| 2026-10-11 00:00 |
14:53:32.18 |
-08:28:17.9 |
HIP 72943 |
14.87 |