C/2017 K2 (PANSTARRS)
メタデータ
| 項目 | 値 |
|---|---|
| Designation | C/2017 K2 (PANSTARRS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2022-12-19T17:31:06.729600Z |
| Orbit solution date (soln_date, UTC) | 2026-01-13T08:12:20Z |
| Obs used | 3038 |
| NEO | - |
| M1 | 8.500 |
| 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) | 2021-09-01.0000000 |
| e | 1.00061012 |
| q (au) | 1.797305 |
| a (au) | -2945.808217 |
| i (deg) | 87.554587 |
| Ω (om, deg) | 88.241485 |
| ω (w, deg) | 236.192058 |
| M (ma, deg) | -0.002926 |
等級
散乱 + 全体線形
$$ M_a = (8.365 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
モデル定数
| 項目 | 値 |
|---|---|
| H0 | 8.365 |
| n | 2.000 |
| gf | 0.999 |
| gb | -0.832 |
| k | 0.990 |
| 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 |
|---|---|---|---|
| 2013-05-12 | 2022-05-07 | +0.3939 | -0.795 |
| 2022-05-07 | 2022-12-13 | +8.2289 | -3.838 |
| 2022-12-20 | 2024-01-29 | +6.1078 | -3.847 |
| 2024-01-29 | 2026-01-24 | +3.0630 | -2.147 |
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) |
|---|---|---|---|---|
| 2026-02-03 00:00 | 05:34:06.03 | +31:09:01.7 | HIP 26206 | 18.56 |
| 2026-02-03 12:00 | 05:33:57.17 | +31:09:09.6 | HIP 26206 | 20.02 |
| 2026-02-04 00:00 | 05:33:48.42 | +31:09:17.3 | HIP 26206 | 21.53 |
| 2026-02-04 12:00 | 05:33:39.79 | +31:09:24.9 | HIP 26206 | 23.07 |
| 2026-02-05 00:00 | 05:33:31.26 | +31:09:32.4 | HIP 26206 | 24.64 |
| 2026-02-05 12:00 | 05:33:22.85 | +31:09:39.8 | HIP 26206 | 26.21 |
| 2026-02-06 00:00 | 05:33:14.56 | +31:09:47.0 | HIP 26206 | 27.80 |
| 2026-02-06 12:00 | 05:33:06.37 | +31:09:54.1 | HIP 26206 | 29.38 |
| 2026-02-07 00:00 | 05:32:58.31 | +31:10:01.1 | HIP 26206 | 30.96 |
| 2026-02-07 12:00 | 05:32:50.36 | +31:10:07.9 | HIP 25794 | 31.06 |
| 2026-02-08 00:00 | 05:32:42.52 | +31:10:14.7 | HIP 25794 | 29.40 |
| 2026-02-08 12:00 | 05:32:34.80 | +31:10:21.3 | HIP 25794 | 27.77 |
| 2026-02-09 00:00 | 05:32:27.20 | +31:10:27.9 | HIP 25794 | 26.17 |
| 2026-02-09 12:00 | 05:32:19.71 | +31:10:34.3 | HIP 25794 | 24.59 |
| 2026-02-10 00:00 | 05:32:12.34 | +31:10:40.7 | HIP 25794 | 23.04 |
| 2026-02-10 12:00 | 05:32:05.09 | +31:10:46.9 | HIP 25794 | 21.52 |
| 2026-02-11 00:00 | 05:31:57.95 | +31:10:53.1 | HIP 25794 | 20.04 |
| 2026-02-11 12:00 | 05:31:50.94 | +31:10:59.2 | HIP 25794 | 18.58 |
| 2026-02-12 00:00 | 05:31:44.04 | +31:11:05.2 | HIP 25794 | 17.15 |
| 2026-02-12 12:00 | 05:31:37.26 | +31:11:11.1 | HIP 25794 | 15.76 |
| 2026-02-13 00:00 | 05:31:30.60 | +31:11:17.0 | HIP 25794 | 14.41 |
| 2026-02-13 12:00 | 05:31:24.06 | +31:11:22.7 | HIP 25794 | 13.09 |
| 2026-02-14 00:00 | 05:31:17.64 | +31:11:28.4 | HIP 25794 | 11.82 |
| 2026-02-14 12:00 | 05:31:11.34 | +31:11:34.1 | HIP 25794 | 10.60 |
| 2026-02-15 00:00 | 05:31:05.16 | +31:11:39.6 | HIP 25794 | 9.43 |
| 2026-02-15 12:00 | 05:30:59.10 | +31:11:45.1 | HIP 25794 | 8.33 |
| 2026-02-16 00:00 | 05:30:53.16 | +31:11:50.6 | HIP 25794 | 7.31 |
| 2026-02-16 12:00 | 05:30:47.34 | +31:11:56.0 | HIP 25794 | 6.41 |
| 2026-02-17 00:00 | 05:30:41.64 | +31:12:01.3 | HIP 25794 | 5.65 |
| 2026-02-17 12:00 | 05:30:36.07 | +31:12:06.6 | HIP 25794 | 5.08 |
| 2026-02-18 00:00 | 05:30:30.61 | +31:12:11.9 | HIP 25794 | 4.76 |
| 2026-02-18 12:00 | 05:30:25.28 | +31:12:17.1 | HIP 25794 | 4.70 |
| 2026-02-19 00:00 | 05:30:20.07 | +31:12:22.3 | HIP 25794 | 4.91 |
| 2026-02-19 12:00 | 05:30:14.97 | +31:12:27.4 | HIP 25794 | 5.34 |
| 2026-02-20 00:00 | 05:30:10.01 | +31:12:32.5 | HIP 25794 | 5.92 |
| 2026-02-20 12:00 | 05:30:05.16 | +31:12:37.6 | HIP 25794 | 6.61 |
| 2026-02-21 00:00 | 05:30:00.43 | +31:12:42.6 | HIP 25794 | 7.35 |
| 2026-02-21 12:00 | 05:29:55.83 | +31:12:47.6 | HIP 25794 | 8.14 |
| 2026-02-22 00:00 | 05:29:51.34 | +31:12:52.6 | HIP 25794 | 8.94 |
| 2026-02-22 12:00 | 05:29:46.98 | +31:12:57.6 | HIP 25794 | 9.74 |
| 2026-02-23 00:00 | 05:29:42.74 | +31:13:02.6 | HIP 25794 | 10.55 |
| 2026-02-23 12:00 | 05:29:38.62 | +31:13:07.5 | HIP 25794 | 11.34 |
| 2026-02-24 00:00 | 05:29:34.62 | +31:13:12.5 | HIP 25794 | 12.12 |