P/2017 S8 (PANSTARRS)
メタデータ
| 項目 | 値 |
|---|---|
| Designation | P/2017 S8 (PANSTARRS) |
| Type | P |
| Perihelion (tp_cal, UTC) | 2018-01-28T15:29:27.191040Z |
| Orbit solution date (soln_date, UTC) | 2022-07-31T01:43:24Z |
| Obs used | 178 |
| NEO | - |
| M1 | 18.100 |
| K1 | 4.500 |
| PC | - |
オスキュレーティング軌道要素
| 項目 | 値 |
|---|---|
| Epoch (epoch_cal, TDB) | 2017-10-19.0000000 |
| e | 0.39352874 |
| q (au) | 1.682991 |
| a (au) | 2.775056 |
| i (deg) | 29.851080 |
| Ω (om, deg) | 191.802254 |
| ω (w, deg) | 254.566958 |
| M (ma, deg) | 338.328723 |
等級
散乱 + 全体線形
$$ M_a = (20.000 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
モデル定数
| 項目 | 値 |
|---|---|
| H0 | 20.000 |
| n | 2.000 |
| gf | 0.998 |
| gb | -0.852 |
| k | 0.909 |
| 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 |
|---|---|---|---|
| 2017-09-25 | 2018-01-22 | -24.0653 | +6.668 |
log10 r = log10(太陽距離/AU)、Δ = 地球距離(AU)
ファインディングチャート
天体暦
| Date/Time (UTC) | RA (J2000) | Dec (J2000) | Nearest HIP | Dist from HIP (arcmin) |
|---|---|---|---|---|
| 2026-06-01 00:00 | 23:10:41.55 | +15:19:26.8 | HIP 114542 | 19.88 |
| 2026-06-01 12:00 | 23:11:10.37 | +15:22:57.7 | HIP 114542 | 13.56 |
| 2026-06-02 00:00 | 23:11:39.07 | +15:26:27.9 | HIP 114542 | 9.71 |
| 2026-06-02 12:00 | 23:12:07.63 | +15:29:57.4 | HIP 114542 | 11.16 |
| 2026-06-03 00:00 | 23:12:36.07 | +15:33:26.4 | HIP 114542 | 16.52 |
| 2026-06-03 12:00 | 23:13:04.36 | +15:36:54.6 | HIP 114670 | 18.22 |
| 2026-06-04 00:00 | 23:13:32.53 | +15:40:22.2 | HIP 114670 | 18.69 |
| 2026-06-04 12:00 | 23:14:00.56 | +15:43:49.1 | HIP 114670 | 21.95 |
| 2026-06-05 00:00 | 23:14:28.45 | +15:47:15.4 | HIP 114670 | 26.99 |
| 2026-06-05 12:00 | 23:14:56.21 | +15:50:40.9 | HIP 114723 | 30.33 |
| 2026-06-06 00:00 | 23:15:23.82 | +15:54:05.6 | HIP 114764 | 29.32 |
| 2026-06-06 12:00 | 23:15:51.30 | +15:57:29.7 | HIP 114764 | 28.77 |
| 2026-06-07 00:00 | 23:16:18.63 | +16:00:52.9 | HIP 114764 | 30.09 |
| 2026-06-07 12:00 | 23:16:45.82 | +16:04:15.4 | HIP 115024 | 32.08 |
| 2026-06-08 00:00 | 23:17:12.86 | +16:07:37.1 | HIP 115024 | 26.50 |
| 2026-06-08 12:00 | 23:17:39.76 | +16:10:58.0 | HIP 115024 | 21.97 |
| 2026-06-09 00:00 | 23:18:06.50 | +16:14:18.1 | HIP 115024 | 19.22 |
| 2026-06-09 12:00 | 23:18:33.10 | +16:17:37.3 | HIP 115024 | 18.97 |
| 2026-06-10 00:00 | 23:18:59.55 | +16:20:55.7 | HIP 115024 | 21.28 |
| 2026-06-10 12:00 | 23:19:25.84 | +16:24:13.2 | HIP 115024 | 25.42 |
| 2026-06-11 00:00 | 23:19:51.98 | +16:27:29.8 | HIP 115279 | 21.04 |
| 2026-06-11 12:00 | 23:20:17.96 | +16:30:45.5 | HIP 115279 | 14.55 |
| 2026-06-12 00:00 | 23:20:43.79 | +16:34:00.3 | HIP 115279 | 8.92 |
| 2026-06-12 12:00 | 23:21:09.45 | +16:37:14.1 | HIP 115279 | 6.71 |
| 2026-06-13 00:00 | 23:21:34.96 | +16:40:27.0 | HIP 115359 | 6.06 |
| 2026-06-13 12:00 | 23:22:00.30 | +16:43:38.8 | HIP 115359 | 5.71 |
| 2026-06-14 00:00 | 23:22:25.48 | +16:46:49.7 | HIP 115359 | 11.04 |
| 2026-06-14 12:00 | 23:22:50.49 | +16:49:59.5 | HIP 115359 | 17.39 |
| 2026-06-15 00:00 | 23:23:15.33 | +16:53:08.3 | HIP 115359 | 23.93 |
| 2026-06-15 12:00 | 23:23:40.00 | +16:56:16.1 | HIP 115359 | 30.51 |
| 2026-06-16 00:00 | 23:24:04.51 | +16:59:22.7 | HIP 115359 | 37.08 |
| 2026-06-16 12:00 | 23:24:28.84 | +17:02:28.3 | HIP 115635 | 39.46 |
| 2026-06-17 00:00 | 23:24:52.99 | +17:05:32.7 | HIP 115699 | 33.94 |
| 2026-06-17 12:00 | 23:25:16.98 | +17:08:36.0 | HIP 115699 | 27.91 |
| 2026-06-18 00:00 | 23:25:40.78 | +17:11:38.1 | HIP 115699 | 22.17 |
| 2026-06-18 12:00 | 23:26:04.41 | +17:14:39.0 | HIP 115699 | 16.98 |
| 2026-06-19 00:00 | 23:26:27.86 | +17:17:38.8 | HIP 115699 | 12.94 |
| 2026-06-19 12:00 | 23:26:51.13 | +17:20:37.3 | HIP 115699 | 11.27 |
| 2026-06-20 00:00 | 23:27:14.21 | +17:23:34.6 | HIP 115699 | 12.86 |
| 2026-06-20 12:00 | 23:27:37.12 | +17:26:30.7 | HIP 115699 | 16.75 |
| 2026-06-21 00:00 | 23:27:59.83 | +17:29:25.5 | HIP 115699 | 21.69 |
| 2026-06-21 12:00 | 23:28:22.37 | +17:32:19.0 | HIP 115699 | 27.08 |
| 2026-06-22 00:00 | 23:28:44.71 | +17:35:11.2 | HIP 116047 | 30.05 |