399P/PANSTARRS
メタデータ
| 項目 | 値 |
|---|---|
| Designation | 399P/PANSTARRS |
| Type | P |
| Perihelion (tp_cal, UTC) | 2021-05-26T08:38:38.169600Z |
| Orbit solution date (soln_date, UTC) | 2026-06-09T11:12:48Z |
| Obs used | 411 |
| NEO | - |
| M1 | 15.900 |
| 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) | 2017-11-29.0000000 |
| e | 0.44202403 |
| q (au) | 2.126592 |
| a (au) | 3.811261 |
| i (deg) | 13.345760 |
| Ω (om, deg) | 207.563782 |
| ω (w, deg) | 213.319811 |
| M (ma, deg) | 191.191937 |
等級
散乱 + 全体線形
$$ M_a = (14.631 + 2.270\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
モデル定数
| 項目 | 値 |
|---|---|
| H0 | 14.631 |
| n | 2.270 |
| gf | 0.946 |
| gb | -0.851 |
| k | 0.999 |
| δ90 | 8.448 |
| 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 |
|---|---|---|---|
| 2020-07-30 | 2021-02-17 | +2.5704 | -0.611 |
| 2021-11-02 | 2022-03-07 | -4.0919 | +1.125 |
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) |
|---|---|---|---|---|
| 2026-09-20 00:00 | 17:44:36.33 | -10:26:59.3 | HIP 86832 | 6.82 |
| 2026-09-20 12:00 | 17:44:45.51 | -10:28:11.6 | HIP 86832 | 8.45 |
| 2026-09-21 00:00 | 17:44:54.88 | -10:29:23.6 | HIP 86832 | 10.47 |
| 2026-09-21 12:00 | 17:45:04.46 | -10:30:35.6 | HIP 86832 | 12.73 |
| 2026-09-22 00:00 | 17:45:14.22 | -10:31:47.3 | HIP 86936 | 13.85 |
| 2026-09-22 12:00 | 17:45:24.18 | -10:32:58.9 | HIP 86936 | 13.44 |
| 2026-09-23 00:00 | 17:45:34.33 | -10:34:10.4 | HIP 86936 | 13.55 |
| 2026-09-23 12:00 | 17:45:44.67 | -10:35:21.6 | HIP 86936 | 14.20 |
| 2026-09-24 00:00 | 17:45:55.21 | -10:36:32.7 | HIP 86936 | 15.35 |
| 2026-09-24 12:00 | 17:46:05.93 | -10:37:43.6 | HIP 86936 | 16.91 |
| 2026-09-25 00:00 | 17:46:16.84 | -10:38:54.3 | HIP 86936 | 18.80 |
| 2026-09-25 12:00 | 17:46:27.94 | -10:40:04.8 | HIP 86936 | 20.94 |
| 2026-09-26 00:00 | 17:46:39.23 | -10:41:15.1 | HIP 86936 | 23.29 |
| 2026-09-26 12:00 | 17:46:50.70 | -10:42:25.2 | HIP 86936 | 25.81 |
| 2026-09-27 00:00 | 17:47:02.36 | -10:43:35.0 | HIP 86936 | 28.45 |
| 2026-09-27 12:00 | 17:47:14.21 | -10:44:44.6 | HIP 86936 | 31.20 |
| 2026-09-28 00:00 | 17:47:26.24 | -10:45:54.1 | HIP 86936 | 34.05 |
| 2026-09-28 12:00 | 17:47:38.45 | -10:47:03.2 | HIP 87177 | 34.03 |
| 2026-09-29 00:00 | 17:47:50.84 | -10:48:12.2 | HIP 87177 | 33.89 |
| 2026-09-29 12:00 | 17:48:03.42 | -10:49:20.8 | HIP 87256 | 32.68 |
| 2026-09-30 00:00 | 17:48:16.18 | -10:50:29.3 | HIP 87256 | 31.13 |
| 2026-09-30 12:00 | 17:48:29.12 | -10:51:37.5 | HIP 87256 | 29.84 |
| 2026-10-01 00:00 | 17:48:42.24 | -10:52:45.4 | HIP 87213 | 28.26 |
| 2026-10-01 12:00 | 17:48:55.53 | -10:53:53.0 | HIP 87213 | 26.69 |
| 2026-10-02 00:00 | 17:49:09.01 | -10:55:00.4 | HIP 87213 | 25.50 |
| 2026-10-02 12:00 | 17:49:22.66 | -10:56:07.5 | HIP 87213 | 24.76 |
| 2026-10-03 00:00 | 17:49:36.49 | -10:57:14.3 | HIP 87213 | 24.53 |
| 2026-10-03 12:00 | 17:49:50.50 | -10:58:20.8 | HIP 87213 | 24.85 |
| 2026-10-04 00:00 | 17:50:04.68 | -10:59:27.1 | HIP 87213 | 25.69 |
| 2026-10-04 12:00 | 17:50:19.04 | -11:00:33.0 | HIP 87213 | 27.05 |
| 2026-10-05 00:00 | 17:50:33.57 | -11:01:38.6 | HIP 87424 | 27.39 |
| 2026-10-05 12:00 | 17:50:48.27 | -11:02:43.9 | HIP 87424 | 24.02 |
| 2026-10-06 00:00 | 17:51:03.15 | -11:03:48.9 | HIP 87424 | 20.76 |
| 2026-10-06 12:00 | 17:51:18.20 | -11:04:53.5 | HIP 87424 | 17.69 |
| 2026-10-07 00:00 | 17:51:33.42 | -11:05:57.8 | HIP 87424 | 14.99 |
| 2026-10-07 12:00 | 17:51:48.81 | -11:07:01.8 | HIP 87424 | 12.89 |
| 2026-10-08 00:00 | 17:52:04.37 | -11:08:05.4 | HIP 87424 | 11.79 |
| 2026-10-08 12:00 | 17:52:20.10 | -11:09:08.7 | HIP 87424 | 11.98 |
| 2026-10-09 00:00 | 17:52:36.00 | -11:10:11.6 | HIP 87424 | 13.45 |
| 2026-10-09 12:00 | 17:52:52.06 | -11:11:14.1 | HIP 87424 | 15.88 |
| 2026-10-10 00:00 | 17:53:08.29 | -11:12:16.3 | HIP 87642 | 16.58 |
| 2026-10-10 12:00 | 17:53:24.69 | -11:13:18.1 | HIP 87642 | 12.60 |
| 2026-10-11 00:00 | 17:53:41.25 | -11:14:19.5 | HIP 87642 | 8.76 |