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) |
| 2026-05-12 00:00 |
19:47:43.72 |
-27:30:14.0 |
HIP 97408 |
13.82 |
| 2026-05-12 12:00 |
19:47:42.02 |
-27:30:48.7 |
HIP 97408 |
13.31 |
| 2026-05-13 00:00 |
19:47:40.09 |
-27:31:23.9 |
HIP 97408 |
12.82 |
| 2026-05-13 12:00 |
19:47:37.91 |
-27:31:59.6 |
HIP 97408 |
12.35 |
| 2026-05-14 00:00 |
19:47:35.49 |
-27:32:35.9 |
HIP 97408 |
11.93 |
| 2026-05-14 12:00 |
19:47:32.84 |
-27:33:12.7 |
HIP 97408 |
11.56 |
| 2026-05-15 00:00 |
19:47:29.93 |
-27:33:50.0 |
HIP 97408 |
11.25 |
| 2026-05-15 12:00 |
19:47:26.79 |
-27:34:27.8 |
HIP 97408 |
11.03 |
| 2026-05-16 00:00 |
19:47:23.40 |
-27:35:06.1 |
HIP 97408 |
10.92 |
| 2026-05-16 12:00 |
19:47:19.77 |
-27:35:44.9 |
HIP 97408 |
10.92 |
| 2026-05-17 00:00 |
19:47:15.90 |
-27:36:24.2 |
HIP 97408 |
11.05 |
| 2026-05-17 12:00 |
19:47:11.79 |
-27:37:04.0 |
HIP 97408 |
11.32 |
| 2026-05-18 00:00 |
19:47:07.43 |
-27:37:44.3 |
HIP 97408 |
11.73 |
| 2026-05-18 12:00 |
19:47:02.82 |
-27:38:25.1 |
HIP 97408 |
12.29 |
| 2026-05-19 00:00 |
19:46:57.98 |
-27:39:06.3 |
HIP 97408 |
12.99 |
| 2026-05-19 12:00 |
19:46:52.89 |
-27:39:48.0 |
HIP 97408 |
13.82 |
| 2026-05-20 00:00 |
19:46:47.55 |
-27:40:30.2 |
HIP 97408 |
14.77 |
| 2026-05-20 12:00 |
19:46:41.98 |
-27:41:12.8 |
HIP 97408 |
15.84 |
| 2026-05-21 00:00 |
19:46:36.16 |
-27:41:55.9 |
HIP 97408 |
17.01 |
| 2026-05-21 12:00 |
19:46:30.10 |
-27:42:39.4 |
HIP 97408 |
18.27 |
| 2026-05-22 00:00 |
19:46:23.79 |
-27:43:23.3 |
HIP 97408 |
19.63 |
| 2026-05-22 12:00 |
19:46:17.25 |
-27:44:07.7 |
HIP 97408 |
21.07 |
| 2026-05-23 00:00 |
19:46:10.46 |
-27:44:52.4 |
HIP 97408 |
22.59 |
| 2026-05-23 12:00 |
19:46:03.43 |
-27:45:37.6 |
HIP 97408 |
24.19 |
| 2026-05-24 00:00 |
19:45:56.15 |
-27:46:23.2 |
HIP 97195 |
24.38 |
| 2026-05-24 12:00 |
19:45:48.64 |
-27:47:09.2 |
HIP 97195 |
24.54 |
| 2026-05-25 00:00 |
19:45:40.89 |
-27:47:55.5 |
HIP 97195 |
24.82 |
| 2026-05-25 12:00 |
19:45:32.89 |
-27:48:42.3 |
HIP 97195 |
25.24 |
| 2026-05-26 00:00 |
19:45:24.66 |
-27:49:29.4 |
HIP 97195 |
25.80 |
| 2026-05-26 12:00 |
19:45:16.19 |
-27:50:16.8 |
HIP 97195 |
26.50 |
| 2026-05-27 00:00 |
19:45:07.47 |
-27:51:04.7 |
HIP 97195 |
27.35 |
| 2026-05-27 12:00 |
19:44:58.52 |
-27:51:52.8 |
HIP 97195 |
28.33 |
| 2026-05-28 00:00 |
19:44:49.33 |
-27:52:41.3 |
HIP 97195 |
29.46 |
| 2026-05-28 12:00 |
19:44:39.90 |
-27:53:30.2 |
HIP 97195 |
30.72 |
| 2026-05-29 00:00 |
19:44:30.24 |
-27:54:19.3 |
HIP 97195 |
32.10 |
| 2026-05-29 12:00 |
19:44:20.33 |
-27:55:08.7 |
HIP 97195 |
33.61 |
| 2026-05-30 00:00 |
19:44:10.19 |
-27:55:58.5 |
HIP 97195 |
35.24 |
| 2026-05-30 12:00 |
19:43:59.82 |
-27:56:48.5 |
HIP 97195 |
36.98 |
| 2026-05-31 00:00 |
19:43:49.21 |
-27:57:38.9 |
HIP 97195 |
38.82 |
| 2026-05-31 12:00 |
19:43:38.36 |
-27:58:29.5 |
HIP 97195 |
40.76 |
| 2026-06-01 00:00 |
19:43:27.28 |
-27:59:20.3 |
HIP 96823 |
39.20 |
| 2026-06-01 12:00 |
19:43:15.97 |
-28:00:11.4 |
HIP 96823 |
37.40 |
| 2026-06-02 00:00 |
19:43:04.42 |
-28:01:02.8 |
HIP 96823 |
35.66 |