メタデータ
| 項目 |
値 |
| Designation |
C/2017 U4 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2018-09-25T16:38:00.893760Z |
| Orbit solution date (soln_date, UTC) |
2023-02-13T23:12:42Z |
| Obs used |
85 |
| NEO |
- |
| M1 |
7.100 |
| K1 |
10.750 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2018-01-03.0000000 |
| e |
1.00304382 |
| q (au) |
7.724158 |
| a (au) |
-2537.649728 |
| i (deg) |
158.225721 |
| Ω (om, deg) |
245.952559 |
| ω (w, deg) |
159.177100 |
| M (ma, deg) |
-0.002049 |
等級
散乱 + 全体線形
$$
M_a = (2.306 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
2.306 |
| n |
6.000 |
| gf |
0.993 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
9.974 |
| 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) |
| 2026-07-29 00:00 |
00:12:08.33 |
-22:46:27.2 |
HIP 964 |
4.07 |
| 2026-07-29 12:00 |
00:12:03.13 |
-22:47:34.9 |
HIP 964 |
2.43 |
| 2026-07-30 00:00 |
00:11:57.87 |
-22:48:42.6 |
HIP 964 |
0.79 |
| 2026-07-30 12:00 |
00:11:52.56 |
-22:49:50.5 |
HIP 964 |
0.94 |
| 2026-07-31 00:00 |
00:11:47.20 |
-22:50:58.4 |
HIP 964 |
2.59 |
| 2026-07-31 12:00 |
00:11:41.79 |
-22:52:06.4 |
HIP 964 |
4.27 |
| 2026-08-01 00:00 |
00:11:36.33 |
-22:53:14.5 |
HIP 964 |
5.96 |
| 2026-08-01 12:00 |
00:11:30.81 |
-22:54:22.7 |
HIP 964 |
7.67 |
| 2026-08-02 00:00 |
00:11:25.25 |
-22:55:30.9 |
HIP 964 |
9.38 |
| 2026-08-02 12:00 |
00:11:19.63 |
-22:56:39.2 |
HIP 964 |
11.10 |
| 2026-08-03 00:00 |
00:11:13.97 |
-22:57:47.5 |
HIP 964 |
12.83 |
| 2026-08-03 12:00 |
00:11:08.26 |
-22:58:55.9 |
HIP 964 |
14.57 |
| 2026-08-04 00:00 |
00:11:02.49 |
-23:00:04.4 |
HIP 964 |
16.32 |
| 2026-08-04 12:00 |
00:10:56.68 |
-23:01:12.8 |
HIP 842 |
17.21 |
| 2026-08-05 00:00 |
00:10:50.82 |
-23:02:21.3 |
HIP 842 |
17.64 |
| 2026-08-05 12:00 |
00:10:44.91 |
-23:03:29.9 |
HIP 842 |
18.23 |
| 2026-08-06 00:00 |
00:10:38.95 |
-23:04:38.4 |
HIP 842 |
18.97 |
| 2026-08-06 12:00 |
00:10:32.94 |
-23:05:47.0 |
HIP 842 |
19.84 |
| 2026-08-07 00:00 |
00:10:26.88 |
-23:06:55.6 |
HIP 842 |
20.83 |
| 2026-08-07 12:00 |
00:10:20.78 |
-23:08:04.3 |
HIP 842 |
21.92 |
| 2026-08-08 00:00 |
00:10:14.63 |
-23:09:12.9 |
HIP 842 |
23.10 |
| 2026-08-08 12:00 |
00:10:08.43 |
-23:10:21.5 |
HIP 842 |
24.37 |
| 2026-08-09 00:00 |
00:10:02.19 |
-23:11:30.1 |
HIP 842 |
25.70 |
| 2026-08-09 12:00 |
00:09:55.90 |
-23:12:38.7 |
HIP 842 |
27.10 |
| 2026-08-10 00:00 |
00:09:49.56 |
-23:13:47.3 |
HIP 842 |
28.54 |
| 2026-08-10 12:00 |
00:09:43.18 |
-23:14:55.9 |
HIP 842 |
30.04 |
| 2026-08-11 00:00 |
00:09:36.75 |
-23:16:04.5 |
HIP 842 |
31.58 |
| 2026-08-11 12:00 |
00:09:30.28 |
-23:17:13.0 |
HIP 842 |
33.15 |
| 2026-08-12 00:00 |
00:09:23.76 |
-23:18:21.5 |
HIP 842 |
34.76 |
| 2026-08-12 12:00 |
00:09:17.20 |
-23:19:29.9 |
HIP 586 |
34.38 |
| 2026-08-13 00:00 |
00:09:10.60 |
-23:20:38.3 |
HIP 586 |
33.69 |
| 2026-08-13 12:00 |
00:09:03.95 |
-23:21:46.7 |
HIP 586 |
33.08 |
| 2026-08-14 00:00 |
00:08:57.26 |
-23:22:55.0 |
HIP 586 |
32.57 |
| 2026-08-14 12:00 |
00:08:50.53 |
-23:24:03.2 |
HIP 616 |
30.82 |
| 2026-08-15 00:00 |
00:08:43.75 |
-23:25:11.4 |
HIP 616 |
29.00 |
| 2026-08-15 12:00 |
00:08:36.94 |
-23:26:19.4 |
HIP 616 |
27.19 |
| 2026-08-16 00:00 |
00:08:30.08 |
-23:27:27.4 |
HIP 616 |
25.39 |
| 2026-08-16 12:00 |
00:08:23.18 |
-23:28:35.3 |
HIP 616 |
23.62 |
| 2026-08-17 00:00 |
00:08:16.24 |
-23:29:43.2 |
HIP 616 |
21.87 |
| 2026-08-17 12:00 |
00:08:09.26 |
-23:30:50.9 |
HIP 616 |
20.15 |
| 2026-08-18 00:00 |
00:08:02.25 |
-23:31:58.5 |
HIP 616 |
18.48 |
| 2026-08-18 12:00 |
00:07:55.19 |
-23:33:06.0 |
HIP 616 |
16.87 |
| 2026-08-19 00:00 |
00:07:48.10 |
-23:34:13.5 |
HIP 616 |
15.34 |