メタデータ
| 項目 |
値 |
| Designation |
P/2020 U2 (PANSTARRS) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2020-12-25T16:46:43.095360Z |
| Orbit solution date (soln_date, UTC) |
2021-07-01T22:13:00Z |
| Obs used |
301 |
| NEO |
- |
| M1 |
9.900 |
| K1 |
26.000 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2020-10-20T09:20:45.801600Z |
| Discovery magnitude (MPC) |
21.70 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2021-01-12.0000000 |
| e |
0.51048764 |
| q (au) |
1.848825 |
| a (au) |
3.776871 |
| i (deg) |
6.420975 |
| Ω (om, deg) |
342.901523 |
| ω (w, deg) |
84.644930 |
| M (ma, deg) |
2.323134 |
等級
散乱 + 全体線形
$$
M_a = (12.635 + 5.176\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
12.635 |
| n |
5.176 |
| gf |
1.000 |
| gb |
-0.500 |
| 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) |
| 2026-09-20 00:00 |
18:46:36.52 |
-28:20:04.9 |
HIP 92215 |
13.75 |
| 2026-09-20 12:00 |
18:46:39.94 |
-28:19:12.9 |
HIP 92215 |
12.83 |
| 2026-09-21 00:00 |
18:46:43.61 |
-28:18:20.7 |
HIP 92215 |
11.89 |
| 2026-09-21 12:00 |
18:46:47.55 |
-28:17:28.2 |
HIP 92215 |
10.94 |
| 2026-09-22 00:00 |
18:46:51.75 |
-28:16:35.5 |
HIP 92215 |
10.00 |
| 2026-09-22 12:00 |
18:46:56.21 |
-28:15:42.6 |
HIP 92215 |
9.08 |
| 2026-09-23 00:00 |
18:47:00.92 |
-28:14:49.4 |
HIP 92215 |
8.21 |
| 2026-09-23 12:00 |
18:47:05.90 |
-28:13:56.1 |
HIP 92215 |
7.45 |
| 2026-09-24 00:00 |
18:47:11.13 |
-28:13:02.5 |
HIP 92215 |
6.84 |
| 2026-09-24 12:00 |
18:47:16.62 |
-28:12:08.8 |
HIP 92215 |
6.48 |
| 2026-09-25 00:00 |
18:47:22.37 |
-28:11:14.8 |
HIP 92215 |
6.42 |
| 2026-09-25 12:00 |
18:47:28.37 |
-28:10:20.6 |
HIP 92215 |
6.72 |
| 2026-09-26 00:00 |
18:47:34.62 |
-28:09:26.2 |
HIP 92215 |
7.37 |
| 2026-09-26 12:00 |
18:47:41.13 |
-28:08:31.6 |
HIP 92215 |
8.30 |
| 2026-09-27 00:00 |
18:47:47.88 |
-28:07:36.8 |
HIP 92215 |
9.47 |
| 2026-09-27 12:00 |
18:47:54.89 |
-28:06:41.8 |
HIP 92215 |
10.82 |
| 2026-09-28 00:00 |
18:48:02.15 |
-28:05:46.6 |
HIP 92215 |
12.31 |
| 2026-09-28 12:00 |
18:48:09.66 |
-28:04:51.2 |
HIP 92257 |
11.75 |
| 2026-09-29 00:00 |
18:48:17.41 |
-28:03:55.6 |
HIP 92257 |
11.18 |
| 2026-09-29 12:00 |
18:48:25.42 |
-28:02:59.8 |
HIP 92257 |
10.95 |
| 2026-09-30 00:00 |
18:48:33.67 |
-28:02:03.9 |
HIP 92257 |
11.12 |
| 2026-09-30 12:00 |
18:48:42.16 |
-28:01:07.7 |
HIP 92257 |
11.68 |
| 2026-10-01 00:00 |
18:48:50.91 |
-28:00:11.3 |
HIP 92257 |
12.62 |
| 2026-10-01 12:00 |
18:48:59.89 |
-27:59:14.7 |
HIP 92257 |
13.88 |
| 2026-10-02 00:00 |
18:49:09.12 |
-27:58:17.9 |
HIP 92257 |
15.40 |
| 2026-10-02 12:00 |
18:49:18.59 |
-27:57:20.9 |
HIP 92257 |
17.13 |
| 2026-10-03 00:00 |
18:49:28.30 |
-27:56:23.7 |
HIP 92257 |
19.04 |
| 2026-10-03 12:00 |
18:49:38.26 |
-27:55:26.4 |
HIP 92257 |
21.09 |
| 2026-10-04 00:00 |
18:49:48.45 |
-27:54:28.8 |
HIP 92257 |
23.26 |
| 2026-10-04 12:00 |
18:49:58.89 |
-27:53:31.0 |
HIP 92356 |
24.98 |
| 2026-10-05 00:00 |
18:50:09.56 |
-27:52:33.0 |
HIP 92356 |
26.71 |
| 2026-10-05 12:00 |
18:50:20.47 |
-27:51:34.9 |
HIP 92356 |
28.60 |
| 2026-10-06 00:00 |
18:50:31.61 |
-27:50:36.5 |
HIP 92580 |
28.09 |
| 2026-10-06 12:00 |
18:50:43.00 |
-27:49:37.9 |
HIP 92580 |
27.33 |
| 2026-10-07 00:00 |
18:50:54.61 |
-27:48:39.1 |
HIP 92580 |
26.79 |
| 2026-10-07 12:00 |
18:51:06.46 |
-27:47:40.2 |
HIP 92580 |
26.51 |
| 2026-10-08 00:00 |
18:51:18.55 |
-27:46:41.0 |
HIP 92580 |
26.51 |
| 2026-10-08 12:00 |
18:51:30.86 |
-27:45:41.6 |
HIP 92580 |
26.80 |
| 2026-10-09 00:00 |
18:51:43.41 |
-27:44:42.0 |
HIP 92580 |
27.40 |
| 2026-10-09 12:00 |
18:51:56.19 |
-27:43:42.2 |
HIP 92580 |
28.30 |
| 2026-10-10 00:00 |
18:52:09.19 |
-27:42:42.2 |
HIP 92664 |
28.20 |
| 2026-10-10 12:00 |
18:52:22.43 |
-27:41:42.0 |
HIP 92664 |
28.16 |
| 2026-10-11 00:00 |
18:52:35.89 |
-27:40:41.5 |
HIP 92784 |
26.23 |