78P/Gehrels 2
メタデータ
| 項目 | 値 |
|---|---|
| Designation | 78P/Gehrels 2 |
| Type | P |
| Perihelion (tp_cal, UTC) | 2019-04-03T05:24:15.050880Z |
| Orbit solution date (soln_date, UTC) | 2026-03-07T15:22:14Z |
| Obs used | 6064 |
| NEO | - |
| M1 | 9.100 |
| K1 | 13.250 |
| PC | 0.030 |
オスキュレーティング軌道要素
| 項目 | 値 |
|---|---|
| Epoch (epoch_cal, TDB) | 2016-01-21.0000000 |
| e | 0.46118333 |
| q (au) | 2.013818 |
| a (au) | 3.737483 |
| i (deg) | 6.250321 |
| Ω (om, deg) | 210.558992 |
| ω (w, deg) | 192.733774 |
| M (ma, deg) | 200.646435 |
等級
散乱 + 全体線形
$$ M_a = (7.453 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
モデル定数
| 項目 | 値 |
|---|---|
| H0 | 7.453 |
| n | 6.000 |
| gf | 1.000 |
| gb | -1.000 |
| 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
残差 (区間線形)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| 開始日 (UTC) | 終了日 (UTC) | a | b |
|---|---|---|---|
| 2025-04-25 | 2025-10-23 | -5.9460 | +2.177 |
| 2025-10-23 | 2026-01-12 | +4.4137 | -2.105 |
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) |
|---|---|---|---|---|
| 2026-05-12 00:00 | 02:04:35.17 | +13:04:35.6 | HIP 9782 | 23.69 |
| 2026-05-12 12:00 | 02:05:44.98 | +13:09:46.9 | HIP 9782 | 10.80 |
| 2026-05-13 00:00 | 02:06:54.85 | +13:14:57.0 | HIP 9828 | 14.17 |
| 2026-05-13 12:00 | 02:08:04.78 | +13:20:06.0 | HIP 9828 | 24.37 |
| 2026-05-14 00:00 | 02:09:14.77 | +13:25:13.8 | HIP 10094 | 16.59 |
| 2026-05-14 12:00 | 02:10:24.83 | +13:30:20.4 | HIP 10175 | 12.55 |
| 2026-05-15 00:00 | 02:11:34.94 | +13:35:25.8 | HIP 10175 | 11.83 |
| 2026-05-15 12:00 | 02:12:45.11 | +13:40:29.9 | HIP 10300 | 14.62 |
| 2026-05-16 00:00 | 02:13:55.35 | +13:45:32.8 | HIP 10300 | 20.08 |
| 2026-05-16 12:00 | 02:15:05.64 | +13:50:34.4 | HIP 10300 | 35.01 |
| 2026-05-17 00:00 | 02:16:15.99 | +13:55:34.8 | HIP 10766 | 33.53 |
| 2026-05-17 12:00 | 02:17:26.40 | +14:00:33.8 | HIP 10766 | 16.79 |
| 2026-05-18 00:00 | 02:18:36.87 | +14:05:31.6 | HIP 10766 | 8.54 |
| 2026-05-18 12:00 | 02:19:47.39 | +14:10:28.0 | HIP 10895 | 9.75 |
| 2026-05-19 00:00 | 02:20:57.97 | +14:15:23.1 | HIP 10895 | 11.03 |
| 2026-05-19 12:00 | 02:22:08.61 | +14:20:16.9 | HIP 10895 | 27.96 |
| 2026-05-20 00:00 | 02:23:19.30 | +14:25:09.2 | HIP 11298 | 31.97 |
| 2026-05-20 12:00 | 02:24:30.04 | +14:30:00.2 | HIP 11298 | 14.20 |
| 2026-05-21 00:00 | 02:25:40.84 | +14:34:49.9 | HIP 11298 | 3.88 |
| 2026-05-21 12:00 | 02:26:51.70 | +14:39:38.1 | HIP 11298 | 21.50 |
| 2026-05-22 00:00 | 02:28:02.61 | +14:44:24.9 | HIP 11512 | 5.90 |
| 2026-05-22 12:00 | 02:29:13.57 | +14:49:10.2 | HIP 11512 | 11.90 |
| 2026-05-23 00:00 | 02:30:24.58 | +14:53:54.2 | HIP 11512 | 29.70 |
| 2026-05-23 12:00 | 02:31:35.64 | +14:58:36.7 | HIP 11827 | 18.86 |
| 2026-05-24 00:00 | 02:32:46.76 | +15:03:17.7 | HIP 11843 | 2.17 |
| 2026-05-24 12:00 | 02:33:57.93 | +15:07:57.2 | HIP 11843 | 16.48 |
| 2026-05-25 00:00 | 02:35:09.15 | +15:12:35.3 | HIP 12015 | 11.12 |
| 2026-05-25 12:00 | 02:36:20.42 | +15:17:11.9 | HIP 12125 | 8.52 |
| 2026-05-26 00:00 | 02:37:31.74 | +15:21:46.9 | HIP 12125 | 23.14 |
| 2026-05-26 12:00 | 02:38:43.11 | +15:26:20.4 | HIP 12349 | 34.94 |
| 2026-05-27 00:00 | 02:39:54.53 | +15:30:52.4 | HIP 12553 | 23.97 |
| 2026-05-27 12:00 | 02:41:06.00 | +15:35:22.9 | HIP 12553 | 6.33 |
| 2026-05-28 00:00 | 02:42:17.52 | +15:39:51.8 | HIP 12553 | 11.78 |
| 2026-05-28 12:00 | 02:43:29.08 | +15:44:19.1 | HIP 12763 | 12.22 |
| 2026-05-29 00:00 | 02:44:40.70 | +15:48:44.9 | HIP 12763 | 16.99 |
| 2026-05-29 12:00 | 02:45:52.36 | +15:53:09.1 | HIP 12742 | 32.39 |
| 2026-05-30 00:00 | 02:47:04.07 | +15:57:31.6 | HIP 13069 | 30.14 |
| 2026-05-30 12:00 | 02:48:15.83 | +16:01:52.6 | HIP 13145 | 12.85 |
| 2026-05-31 00:00 | 02:49:27.63 | +16:06:11.9 | HIP 13145 | 5.75 |
| 2026-05-31 12:00 | 02:50:39.48 | +16:10:29.7 | HIP 13145 | 23.10 |
| 2026-06-01 00:00 | 02:51:51.38 | +16:14:45.7 | HIP 13358 | 15.11 |
| 2026-06-01 12:00 | 02:53:03.32 | +16:19:00.1 | HIP 13448 | 10.21 |
| 2026-06-02 00:00 | 02:54:15.30 | +16:23:12.9 | HIP 13601 | 15.58 |