メタデータ
| 項目 |
値 |
| Designation |
C/2017 P2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-12-06T13:31:41.891520Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:35Z |
| Obs used |
50 |
| NEO |
- |
| M1 |
9.300 |
| K1 |
23.750 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2017-09-13.0000000 |
| e |
0.99796653 |
| q (au) |
2.461777 |
| a (au) |
1210.625678 |
| i (deg) |
50.084856 |
| Ω (om, deg) |
165.546359 |
| ω (w, deg) |
132.238805 |
| M (ma, deg) |
359.998021 |
等級
散乱 + 全体線形
$$
M_a = (16.551 + 5.128\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
16.551 |
| n |
5.128 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.800 |
| 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) |
| 2026-07-29 00:00 |
05:39:01.62 |
-25:12:33.1 |
HIP 26610 |
5.50 |
| 2026-07-29 12:00 |
05:39:06.61 |
-25:13:10.2 |
HIP 26610 |
4.23 |
| 2026-07-30 00:00 |
05:39:11.57 |
-25:13:47.8 |
HIP 26610 |
2.97 |
| 2026-07-30 12:00 |
05:39:16.50 |
-25:14:25.6 |
HIP 26610 |
1.75 |
| 2026-07-31 00:00 |
05:39:21.39 |
-25:15:03.9 |
HIP 26610 |
0.79 |
| 2026-07-31 12:00 |
05:39:26.26 |
-25:15:42.6 |
HIP 26610 |
1.21 |
| 2026-08-01 00:00 |
05:39:31.09 |
-25:16:21.6 |
HIP 26610 |
2.35 |
| 2026-08-01 12:00 |
05:39:35.89 |
-25:17:01.0 |
HIP 26610 |
3.58 |
| 2026-08-02 00:00 |
05:39:40.66 |
-25:17:40.8 |
HIP 26610 |
4.83 |
| 2026-08-02 12:00 |
05:39:45.39 |
-25:18:20.9 |
HIP 26610 |
6.08 |
| 2026-08-03 00:00 |
05:39:50.10 |
-25:19:01.4 |
HIP 26610 |
7.34 |
| 2026-08-03 12:00 |
05:39:54.76 |
-25:19:42.3 |
HIP 26610 |
8.59 |
| 2026-08-04 00:00 |
05:39:59.40 |
-25:20:23.6 |
HIP 26610 |
9.84 |
| 2026-08-04 12:00 |
05:40:04.00 |
-25:21:05.2 |
HIP 26610 |
11.09 |
| 2026-08-05 00:00 |
05:40:08.57 |
-25:21:47.2 |
HIP 26610 |
12.34 |
| 2026-08-05 12:00 |
05:40:13.10 |
-25:22:29.5 |
HIP 26610 |
13.58 |
| 2026-08-06 00:00 |
05:40:17.60 |
-25:23:12.2 |
HIP 26755 |
12.46 |
| 2026-08-06 12:00 |
05:40:22.06 |
-25:23:55.2 |
HIP 26755 |
11.22 |
| 2026-08-07 00:00 |
05:40:26.49 |
-25:24:38.6 |
HIP 26755 |
9.99 |
| 2026-08-07 12:00 |
05:40:30.88 |
-25:25:22.4 |
HIP 26755 |
8.75 |
| 2026-08-08 00:00 |
05:40:35.23 |
-25:26:06.5 |
HIP 26755 |
7.53 |
| 2026-08-08 12:00 |
05:40:39.55 |
-25:26:50.9 |
HIP 26755 |
6.30 |
| 2026-08-09 00:00 |
05:40:43.83 |
-25:27:35.7 |
HIP 26755 |
5.08 |
| 2026-08-09 12:00 |
05:40:48.08 |
-25:28:20.8 |
HIP 26755 |
3.87 |
| 2026-08-10 00:00 |
05:40:52.29 |
-25:29:06.3 |
HIP 26755 |
2.66 |
| 2026-08-10 12:00 |
05:40:56.46 |
-25:29:52.1 |
HIP 26755 |
1.48 |
| 2026-08-11 00:00 |
05:41:00.59 |
-25:30:38.2 |
HIP 26755 |
0.47 |
| 2026-08-11 12:00 |
05:41:04.68 |
-25:31:24.7 |
HIP 26755 |
1.09 |
| 2026-08-12 00:00 |
05:41:08.74 |
-25:32:11.5 |
HIP 26755 |
2.25 |
| 2026-08-12 12:00 |
05:41:12.76 |
-25:32:58.6 |
HIP 26755 |
3.43 |
| 2026-08-13 00:00 |
05:41:16.73 |
-25:33:46.0 |
HIP 26755 |
4.62 |
| 2026-08-13 12:00 |
05:41:20.67 |
-25:34:33.7 |
HIP 26755 |
5.81 |
| 2026-08-14 00:00 |
05:41:24.57 |
-25:35:21.8 |
HIP 26755 |
7.00 |
| 2026-08-14 12:00 |
05:41:28.43 |
-25:36:10.2 |
HIP 26755 |
8.19 |
| 2026-08-15 00:00 |
05:41:32.25 |
-25:36:58.8 |
HIP 26755 |
9.37 |
| 2026-08-15 12:00 |
05:41:36.03 |
-25:37:47.8 |
HIP 26755 |
10.55 |
| 2026-08-16 00:00 |
05:41:39.77 |
-25:38:37.1 |
HIP 26755 |
11.72 |
| 2026-08-16 12:00 |
05:41:43.46 |
-25:39:26.6 |
HIP 26755 |
12.90 |
| 2026-08-17 00:00 |
05:41:47.12 |
-25:40:16.5 |
HIP 26725 |
14.01 |
| 2026-08-17 12:00 |
05:41:50.73 |
-25:41:06.7 |
HIP 26725 |
14.84 |
| 2026-08-18 00:00 |
05:41:54.31 |
-25:41:57.1 |
HIP 26725 |
15.71 |
| 2026-08-18 12:00 |
05:41:57.84 |
-25:42:47.8 |
HIP 26725 |
16.60 |
| 2026-08-19 00:00 |
05:42:01.33 |
-25:43:38.8 |
HIP 26725 |
17.52 |