C/2017 P2 (PANSTARRS)

メタデータ

項目
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
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

C/2017 P2 (PANSTARRS) · Magnitude (Full range)

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
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)
2026-06-01 00:00 05:27:17.43 -24:51:09.8 HIP 25521 29.43
2026-06-01 12:00 05:27:23.81 -24:50:53.5 HIP 25521 29.62
2026-06-02 00:00 05:27:30.19 -24:50:37.7 HIP 25521 29.88
2026-06-02 12:00 05:27:36.59 -24:50:22.4 HIP 25521 30.19
2026-06-03 00:00 05:27:42.99 -24:50:07.6 HIP 25521 30.57
2026-06-03 12:00 05:27:49.40 -24:49:53.3 HIP 25521 31.01
2026-06-04 00:00 05:27:55.81 -24:49:39.4 HIP 25521 31.50
2026-06-04 12:00 05:28:02.23 -24:49:26.0 HIP 25521 32.04
2026-06-05 00:00 05:28:08.66 -24:49:13.1 HIP 25697 32.17
2026-06-05 12:00 05:28:15.09 -24:49:00.7 HIP 25697 31.68
2026-06-06 00:00 05:28:21.53 -24:48:48.7 HIP 25697 31.24
2026-06-06 12:00 05:28:27.97 -24:48:37.2 HIP 25697 30.86
2026-06-07 00:00 05:28:34.42 -24:48:26.2 HIP 25697 30.54
2026-06-07 12:00 05:28:40.87 -24:48:15.7 HIP 25697 30.28
2026-06-08 00:00 05:28:47.33 -24:48:05.7 HIP 25824 29.92
2026-06-08 12:00 05:28:53.78 -24:47:56.2 HIP 25824 28.60
2026-06-09 00:00 05:29:00.25 -24:47:47.1 HIP 25824 27.29
2026-06-09 12:00 05:29:06.71 -24:47:38.5 HIP 25824 26.00
2026-06-10 00:00 05:29:13.18 -24:47:30.4 HIP 25824 24.72
2026-06-10 12:00 05:29:19.65 -24:47:22.8 HIP 25824 23.46
2026-06-11 00:00 05:29:26.12 -24:47:15.7 HIP 25824 22.22
2026-06-11 12:00 05:29:32.59 -24:47:09.1 HIP 25824 21.01
2026-06-12 00:00 05:29:39.06 -24:47:03.0 HIP 25824 19.83
2026-06-12 12:00 05:29:45.54 -24:46:57.3 HIP 25824 18.68
2026-06-13 00:00 05:29:52.01 -24:46:52.1 HIP 25824 17.58
2026-06-13 12:00 05:29:58.49 -24:46:47.5 HIP 25824 16.53
2026-06-14 00:00 05:30:04.96 -24:46:43.3 HIP 25824 15.55
2026-06-14 12:00 05:30:11.43 -24:46:39.6 HIP 25824 14.64
2026-06-15 00:00 05:30:17.91 -24:46:36.3 HIP 25824 13.81
2026-06-15 12:00 05:30:24.38 -24:46:33.6 HIP 25824 13.10
2026-06-16 00:00 05:30:30.84 -24:46:31.4 HIP 25824 12.51
2026-06-16 12:00 05:30:37.31 -24:46:29.6 HIP 25824 12.06
2026-06-17 00:00 05:30:43.77 -24:46:28.4 HIP 25824 11.77
2026-06-17 12:00 05:30:50.23 -24:46:27.6 HIP 25891 10.94
2026-06-18 00:00 05:30:56.69 -24:46:27.3 HIP 25891 9.49
2026-06-18 12:00 05:31:03.14 -24:46:27.6 HIP 25891 8.05
2026-06-19 00:00 05:31:09.59 -24:46:28.3 HIP 25891 6.61
2026-06-19 12:00 05:31:16.03 -24:46:29.4 HIP 25891 5.19
2026-06-20 00:00 05:31:22.47 -24:46:31.1 HIP 25891 3.79
2026-06-20 12:00 05:31:28.90 -24:46:33.3 HIP 25891 2.47
2026-06-21 00:00 05:31:35.32 -24:46:35.9 HIP 25891 1.44
2026-06-21 12:00 05:31:41.74 -24:46:39.0 HIP 25891 1.50
2026-06-22 00:00 05:31:48.16 -24:46:42.6 HIP 25891 2.59