メタデータ
| 項目 |
値 |
| Designation |
C/2017 U7 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2019-09-11T17:19:45.906240Z |
| Orbit solution date (soln_date, UTC) |
2024-05-30T01:12:17Z |
| Obs used |
915 |
| NEO |
- |
| M1 |
6.300 |
| K1 |
8.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2017-10-29T07:49:16.032000Z |
| Discovery magnitude (MPC) |
20.10 i |
| 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) |
2020-01-08.0000000 |
| e |
1.00164840 |
| q (au) |
6.417510 |
| a (au) |
-3893.179319 |
| i (deg) |
142.635219 |
| Ω (om, deg) |
276.232353 |
| ω (w, deg) |
326.068994 |
| M (ma, deg) |
0.000480 |
等級
散乱 + 全体線形
$$
M_a = (-0.376 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
-0.376 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.958 |
| 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
残差 (区間線形)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| 開始日 (UTC) |
終了日 (UTC) |
a |
b |
| 2017-08-18 |
2019-09-07 |
+24.0875 |
-19.664 |
| 2019-09-15 |
2022-08-03 |
+3.9040 |
-3.583 |
log10 r = log10(太陽距離/AU)、Δ = 地球距離(AU)
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
14:51:14.25 |
+21:39:55.5 |
HIP 72646 |
38.08 |
| 2026-05-12 12:00 |
14:51:04.83 |
+21:40:30.0 |
HIP 72646 |
37.52 |
| 2026-05-13 00:00 |
14:50:55.42 |
+21:41:03.8 |
HIP 72646 |
37.10 |
| 2026-05-13 12:00 |
14:50:46.03 |
+21:41:36.9 |
HIP 72646 |
36.83 |
| 2026-05-14 00:00 |
14:50:36.65 |
+21:42:09.3 |
HIP 72382 |
36.48 |
| 2026-05-14 12:00 |
14:50:27.28 |
+21:42:41.1 |
HIP 72382 |
34.30 |
| 2026-05-15 00:00 |
14:50:17.93 |
+21:43:12.1 |
HIP 72382 |
32.14 |
| 2026-05-15 12:00 |
14:50:08.59 |
+21:43:42.5 |
HIP 72382 |
29.99 |
| 2026-05-16 00:00 |
14:49:59.26 |
+21:44:12.2 |
HIP 72382 |
27.85 |
| 2026-05-16 12:00 |
14:49:49.96 |
+21:44:41.2 |
HIP 72382 |
25.73 |
| 2026-05-17 00:00 |
14:49:40.67 |
+21:45:09.5 |
HIP 72382 |
23.63 |
| 2026-05-17 12:00 |
14:49:31.40 |
+21:45:37.1 |
HIP 72382 |
21.56 |
| 2026-05-18 00:00 |
14:49:22.15 |
+21:46:04.0 |
HIP 72382 |
19.52 |
| 2026-05-18 12:00 |
14:49:12.91 |
+21:46:30.2 |
HIP 72382 |
17.51 |
| 2026-05-19 00:00 |
14:49:03.70 |
+21:46:55.7 |
HIP 72382 |
15.56 |
| 2026-05-19 12:00 |
14:48:54.51 |
+21:47:20.6 |
HIP 72382 |
13.67 |
| 2026-05-20 00:00 |
14:48:45.34 |
+21:47:44.7 |
HIP 72382 |
11.89 |
| 2026-05-20 12:00 |
14:48:36.19 |
+21:48:08.2 |
HIP 72382 |
10.25 |
| 2026-05-21 00:00 |
14:48:27.07 |
+21:48:30.9 |
HIP 72382 |
8.83 |
| 2026-05-21 12:00 |
14:48:17.97 |
+21:48:53.0 |
HIP 72382 |
7.75 |
| 2026-05-22 00:00 |
14:48:08.89 |
+21:49:14.4 |
HIP 72382 |
7.16 |
| 2026-05-22 12:00 |
14:47:59.84 |
+21:49:35.1 |
HIP 72382 |
7.18 |
| 2026-05-23 00:00 |
14:47:50.81 |
+21:49:55.1 |
HIP 72382 |
7.78 |
| 2026-05-23 12:00 |
14:47:41.81 |
+21:50:14.4 |
HIP 72382 |
8.85 |
| 2026-05-24 00:00 |
14:47:32.84 |
+21:50:33.0 |
HIP 72382 |
10.24 |
| 2026-05-24 12:00 |
14:47:23.89 |
+21:50:50.9 |
HIP 72382 |
11.83 |
| 2026-05-25 00:00 |
14:47:14.98 |
+21:51:08.2 |
HIP 72382 |
13.55 |
| 2026-05-25 12:00 |
14:47:06.09 |
+21:51:24.8 |
HIP 72382 |
15.34 |
| 2026-05-26 00:00 |
14:46:57.23 |
+21:51:40.7 |
HIP 72382 |
17.19 |
| 2026-05-26 12:00 |
14:46:48.40 |
+21:51:55.9 |
HIP 72205 |
16.43 |
| 2026-05-27 00:00 |
14:46:39.60 |
+21:52:10.4 |
HIP 72205 |
15.01 |
| 2026-05-27 12:00 |
14:46:30.83 |
+21:52:24.3 |
HIP 72205 |
13.78 |
| 2026-05-28 00:00 |
14:46:22.09 |
+21:52:37.5 |
HIP 72205 |
12.76 |
| 2026-05-28 12:00 |
14:46:13.39 |
+21:52:50.0 |
HIP 72205 |
12.02 |
| 2026-05-29 00:00 |
14:46:04.72 |
+21:53:01.9 |
HIP 72205 |
11.60 |
| 2026-05-29 12:00 |
14:45:56.08 |
+21:53:13.0 |
HIP 72205 |
11.54 |
| 2026-05-30 00:00 |
14:45:47.47 |
+21:53:23.5 |
HIP 72205 |
11.83 |
| 2026-05-30 12:00 |
14:45:38.90 |
+21:53:33.4 |
HIP 72205 |
12.45 |
| 2026-05-31 00:00 |
14:45:30.37 |
+21:53:42.5 |
HIP 72205 |
13.34 |
| 2026-05-31 12:00 |
14:45:21.87 |
+21:53:51.1 |
HIP 72205 |
14.46 |
| 2026-06-01 00:00 |
14:45:13.40 |
+21:53:58.9 |
HIP 72205 |
15.74 |
| 2026-06-01 12:00 |
14:45:04.97 |
+21:54:06.1 |
HIP 72205 |
17.16 |
| 2026-06-02 00:00 |
14:44:56.58 |
+21:54:12.6 |
HIP 72205 |
18.67 |