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 · 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 |
0.990 |
| gb |
-0.500 |
| k |
0.800 |
| δ90 |
5.672 |
| 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) |
| 2026-05-12 00:00 |
15:05:13.04 |
-08:51:45.8 |
HIP 73781 |
6.08 |
| 2026-05-12 12:00 |
15:05:02.47 |
-08:50:52.8 |
HIP 73781 |
3.38 |
| 2026-05-13 00:00 |
15:04:51.90 |
-08:50:00.0 |
HIP 73781 |
1.07 |
| 2026-05-13 12:00 |
15:04:41.34 |
-08:49:07.4 |
HIP 73781 |
2.45 |
| 2026-05-14 00:00 |
15:04:30.80 |
-08:48:15.0 |
HIP 73781 |
5.10 |
| 2026-05-14 12:00 |
15:04:20.27 |
-08:47:22.9 |
HIP 73781 |
7.81 |
| 2026-05-15 00:00 |
15:04:09.75 |
-08:46:31.0 |
HIP 73781 |
10.54 |
| 2026-05-15 12:00 |
15:03:59.25 |
-08:45:39.3 |
HIP 73781 |
13.26 |
| 2026-05-16 00:00 |
15:03:48.76 |
-08:44:47.9 |
HIP 73781 |
15.99 |
| 2026-05-16 12:00 |
15:03:38.29 |
-08:43:56.6 |
HIP 73781 |
18.71 |
| 2026-05-17 00:00 |
15:03:27.84 |
-08:43:05.7 |
HIP 73781 |
21.42 |
| 2026-05-17 12:00 |
15:03:17.41 |
-08:42:15.0 |
HIP 73781 |
24.13 |
| 2026-05-18 00:00 |
15:03:06.99 |
-08:41:24.5 |
HIP 73523 |
25.77 |
| 2026-05-18 12:00 |
15:02:56.60 |
-08:40:34.3 |
HIP 73523 |
23.16 |
| 2026-05-19 00:00 |
15:02:46.23 |
-08:39:44.4 |
HIP 73523 |
20.58 |
| 2026-05-19 12:00 |
15:02:35.88 |
-08:38:54.7 |
HIP 73523 |
18.03 |
| 2026-05-20 00:00 |
15:02:25.55 |
-08:38:05.2 |
HIP 73523 |
15.55 |
| 2026-05-20 12:00 |
15:02:15.25 |
-08:37:16.1 |
HIP 73523 |
13.14 |
| 2026-05-21 00:00 |
15:02:04.97 |
-08:36:27.2 |
HIP 73523 |
10.87 |
| 2026-05-21 12:00 |
15:01:54.72 |
-08:35:38.6 |
HIP 73523 |
8.84 |
| 2026-05-22 00:00 |
15:01:44.49 |
-08:34:50.3 |
HIP 73523 |
7.23 |
| 2026-05-22 12:00 |
15:01:34.30 |
-08:34:02.2 |
HIP 73523 |
6.36 |
| 2026-05-23 00:00 |
15:01:24.12 |
-08:33:14.4 |
HIP 73523 |
6.53 |
| 2026-05-23 12:00 |
15:01:13.98 |
-08:32:27.0 |
HIP 73473 |
4.07 |
| 2026-05-24 00:00 |
15:01:03.87 |
-08:31:39.8 |
HIP 73473 |
1.45 |
| 2026-05-24 12:00 |
15:00:53.79 |
-08:30:52.9 |
HIP 73473 |
1.17 |
| 2026-05-25 00:00 |
15:00:43.74 |
-08:30:06.3 |
HIP 73473 |
3.77 |
| 2026-05-25 12:00 |
15:00:33.72 |
-08:29:20.0 |
HIP 73473 |
6.36 |
| 2026-05-26 00:00 |
15:00:23.73 |
-08:28:33.9 |
HIP 73473 |
8.95 |
| 2026-05-26 12:00 |
15:00:13.78 |
-08:27:48.2 |
HIP 73473 |
11.52 |
| 2026-05-27 00:00 |
15:00:03.86 |
-08:27:02.8 |
HIP 73473 |
14.09 |
| 2026-05-27 12:00 |
14:59:53.97 |
-08:26:17.7 |
HIP 73473 |
16.65 |
| 2026-05-28 00:00 |
14:59:44.13 |
-08:25:32.9 |
HIP 73473 |
19.19 |
| 2026-05-28 12:00 |
14:59:34.31 |
-08:24:48.5 |
HIP 73473 |
21.73 |
| 2026-05-29 00:00 |
14:59:24.54 |
-08:24:04.3 |
HIP 73255 |
24.18 |
| 2026-05-29 12:00 |
14:59:14.80 |
-08:23:20.4 |
HIP 73255 |
23.17 |
| 2026-05-30 00:00 |
14:59:05.10 |
-08:22:36.9 |
HIP 73255 |
22.40 |
| 2026-05-30 12:00 |
14:58:55.43 |
-08:21:53.7 |
HIP 73255 |
21.89 |
| 2026-05-31 00:00 |
14:58:45.81 |
-08:21:10.8 |
HIP 73255 |
21.66 |
| 2026-05-31 12:00 |
14:58:36.23 |
-08:20:28.3 |
HIP 73255 |
21.70 |
| 2026-06-01 00:00 |
14:58:26.69 |
-08:19:46.0 |
HIP 73255 |
22.02 |
| 2026-06-01 12:00 |
14:58:17.19 |
-08:19:04.1 |
HIP 73255 |
22.60 |
| 2026-06-02 00:00 |
14:58:07.73 |
-08:18:22.6 |
HIP 73255 |
23.42 |