メタデータ
| 項目 |
値 |
| Designation |
P/2017 G2 (PANSTARRS) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2017-06-13T21:56:20.866560Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:32Z |
| Obs used |
165 |
| NEO |
- |
| M1 |
12.900 |
| K1 |
10.000 |
| PC |
0.030 |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2017-05-16.0000000 |
| e |
0.65031280 |
| q (au) |
2.846253 |
| a (au) |
8.139426 |
| i (deg) |
47.906245 |
| Ω (om, deg) |
79.819627 |
| ω (w, deg) |
105.939134 |
| M (ma, deg) |
358.772777 |
等級
散乱 + 全体線形
$$
M_a = (9.648 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
9.648 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.539 |
| 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 |
01:32:22.13 |
-40:46:18.6 |
HIP 7017 |
23.20 |
| 2026-05-12 12:00 |
01:32:33.46 |
-40:46:20.7 |
HIP 7336 |
22.26 |
| 2026-05-13 00:00 |
01:32:44.76 |
-40:46:23.6 |
HIP 7336 |
20.15 |
| 2026-05-13 12:00 |
01:32:56.02 |
-40:46:27.4 |
HIP 7336 |
18.04 |
| 2026-05-14 00:00 |
01:33:07.24 |
-40:46:32.0 |
HIP 7336 |
15.94 |
| 2026-05-14 12:00 |
01:33:18.44 |
-40:46:37.4 |
HIP 7336 |
13.86 |
| 2026-05-15 00:00 |
01:33:29.59 |
-40:46:43.6 |
HIP 7336 |
11.79 |
| 2026-05-15 12:00 |
01:33:40.71 |
-40:46:50.7 |
HIP 7336 |
9.74 |
| 2026-05-16 00:00 |
01:33:51.79 |
-40:46:58.7 |
HIP 7336 |
7.73 |
| 2026-05-16 12:00 |
01:34:02.83 |
-40:47:07.4 |
HIP 7336 |
5.77 |
| 2026-05-17 00:00 |
01:34:13.83 |
-40:47:17.0 |
HIP 7336 |
3.96 |
| 2026-05-17 12:00 |
01:34:24.79 |
-40:47:27.5 |
HIP 7336 |
2.60 |
| 2026-05-18 00:00 |
01:34:35.72 |
-40:47:38.7 |
HIP 7336 |
2.53 |
| 2026-05-18 12:00 |
01:34:46.60 |
-40:47:50.8 |
HIP 7336 |
3.81 |
| 2026-05-19 00:00 |
01:34:57.44 |
-40:48:03.8 |
HIP 7336 |
5.58 |
| 2026-05-19 12:00 |
01:35:08.24 |
-40:48:17.5 |
HIP 7336 |
7.48 |
| 2026-05-20 00:00 |
01:35:19.00 |
-40:48:32.1 |
HIP 7336 |
9.44 |
| 2026-05-20 12:00 |
01:35:29.72 |
-40:48:47.6 |
HIP 7336 |
11.43 |
| 2026-05-21 00:00 |
01:35:40.39 |
-40:49:03.8 |
HIP 7336 |
13.42 |
| 2026-05-21 12:00 |
01:35:51.02 |
-40:49:20.9 |
HIP 7336 |
15.41 |
| 2026-05-22 00:00 |
01:36:01.60 |
-40:49:38.8 |
HIP 7336 |
17.41 |
| 2026-05-22 12:00 |
01:36:12.14 |
-40:49:57.5 |
HIP 7336 |
19.40 |
| 2026-05-23 00:00 |
01:36:22.63 |
-40:50:17.1 |
HIP 7336 |
21.38 |
| 2026-05-23 12:00 |
01:36:33.08 |
-40:50:37.4 |
HIP 7336 |
23.37 |
| 2026-05-24 00:00 |
01:36:43.48 |
-40:50:58.6 |
HIP 7336 |
25.35 |
| 2026-05-24 12:00 |
01:36:53.84 |
-40:51:20.6 |
HIP 7336 |
27.32 |
| 2026-05-25 00:00 |
01:37:04.15 |
-40:51:43.4 |
HIP 7484 |
27.85 |
| 2026-05-25 12:00 |
01:37:14.41 |
-40:52:07.0 |
HIP 7484 |
28.07 |
| 2026-05-26 00:00 |
01:37:24.62 |
-40:52:31.5 |
HIP 7675 |
28.34 |
| 2026-05-26 12:00 |
01:37:34.79 |
-40:52:56.7 |
HIP 7675 |
27.65 |
| 2026-05-27 00:00 |
01:37:44.90 |
-40:53:22.8 |
HIP 7760 |
26.77 |
| 2026-05-27 12:00 |
01:37:54.97 |
-40:53:49.6 |
HIP 7760 |
25.23 |
| 2026-05-28 00:00 |
01:38:04.98 |
-40:54:17.3 |
HIP 7760 |
23.77 |
| 2026-05-28 12:00 |
01:38:14.95 |
-40:54:45.8 |
HIP 7760 |
22.39 |
| 2026-05-29 00:00 |
01:38:24.86 |
-40:55:15.0 |
HIP 7760 |
21.13 |
| 2026-05-29 12:00 |
01:38:34.72 |
-40:55:45.1 |
HIP 7760 |
19.98 |
| 2026-05-30 00:00 |
01:38:44.53 |
-40:56:16.0 |
HIP 7760 |
18.99 |
| 2026-05-30 12:00 |
01:38:54.29 |
-40:56:47.7 |
HIP 7760 |
18.16 |
| 2026-05-31 00:00 |
01:39:04.00 |
-40:57:20.1 |
HIP 7760 |
17.52 |
| 2026-05-31 12:00 |
01:39:13.65 |
-40:57:53.4 |
HIP 7760 |
17.08 |
| 2026-06-01 00:00 |
01:39:23.25 |
-40:58:27.5 |
HIP 7760 |
16.87 |
| 2026-06-01 12:00 |
01:39:32.79 |
-40:59:02.3 |
HIP 7827 |
16.19 |
| 2026-06-02 00:00 |
01:39:42.28 |
-40:59:38.0 |
HIP 7827 |
14.41 |