メタデータ
| 項目 |
値 |
| Designation |
C/2017 X1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2018-06-14T10:45:05.999040Z |
| Orbit solution date (soln_date, UTC) |
2021-09-04T23:42:57Z |
| Obs used |
127 |
| NEO |
- |
| M1 |
7.000 |
| K1 |
13.500 |
| PC |
0.030 |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2018-02-14.0000000 |
| e |
0.85110910 |
| q (au) |
4.662645 |
| a (au) |
31.315852 |
| i (deg) |
31.310998 |
| Ω (om, deg) |
251.126772 |
| ω (w, deg) |
283.106326 |
| M (ma, deg) |
359.322581 |
等級
散乱 + 全体線形
$$
M_a = (5.561 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
5.561 |
| 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 |
| 2017-02-12 |
2018-06-07 |
+17.3813 |
-12.086 |
| 2018-07-17 |
2019-07-25 |
-2.0175 |
+1.329 |
log10 r = log10(太陽距離/AU)、Δ = 地球距離(AU)
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
19:43:26.91 |
+02:28:23.5 |
HIP 97121 |
17.83 |
| 2026-05-12 12:00 |
19:43:24.77 |
+02:29:03.7 |
HIP 97121 |
18.68 |
| 2026-05-13 00:00 |
19:43:22.57 |
+02:29:43.6 |
HIP 97121 |
19.53 |
| 2026-05-13 12:00 |
19:43:20.32 |
+02:30:23.3 |
HIP 97121 |
20.40 |
| 2026-05-14 00:00 |
19:43:18.01 |
+02:31:02.7 |
HIP 97121 |
21.27 |
| 2026-05-14 12:00 |
19:43:15.65 |
+02:31:41.8 |
HIP 97121 |
22.15 |
| 2026-05-15 00:00 |
19:43:13.24 |
+02:32:20.6 |
HIP 97121 |
23.03 |
| 2026-05-15 12:00 |
19:43:10.77 |
+02:32:59.1 |
HIP 97121 |
23.92 |
| 2026-05-16 00:00 |
19:43:08.25 |
+02:33:37.4 |
HIP 97121 |
24.82 |
| 2026-05-16 12:00 |
19:43:05.67 |
+02:34:15.4 |
HIP 97121 |
25.72 |
| 2026-05-17 00:00 |
19:43:03.05 |
+02:34:53.0 |
HIP 97121 |
26.63 |
| 2026-05-17 12:00 |
19:43:00.37 |
+02:35:30.4 |
HIP 97121 |
27.54 |
| 2026-05-18 00:00 |
19:42:57.63 |
+02:36:07.5 |
HIP 97121 |
28.46 |
| 2026-05-18 12:00 |
19:42:54.85 |
+02:36:44.2 |
HIP 97121 |
29.39 |
| 2026-05-19 00:00 |
19:42:52.02 |
+02:37:20.7 |
HIP 97121 |
30.32 |
| 2026-05-19 12:00 |
19:42:49.13 |
+02:37:56.9 |
HIP 97121 |
31.25 |
| 2026-05-20 00:00 |
19:42:46.19 |
+02:38:32.7 |
HIP 97121 |
32.20 |
| 2026-05-20 12:00 |
19:42:43.20 |
+02:39:08.3 |
HIP 97121 |
33.14 |
| 2026-05-21 00:00 |
19:42:40.16 |
+02:39:43.5 |
HIP 97121 |
34.10 |
| 2026-05-21 12:00 |
19:42:37.07 |
+02:40:18.4 |
HIP 97121 |
35.06 |
| 2026-05-22 00:00 |
19:42:33.93 |
+02:40:53.0 |
HIP 97121 |
36.02 |
| 2026-05-22 12:00 |
19:42:30.75 |
+02:41:27.3 |
HIP 96774 |
35.83 |
| 2026-05-23 00:00 |
19:42:27.51 |
+02:42:01.2 |
HIP 96774 |
34.89 |
| 2026-05-23 12:00 |
19:42:24.22 |
+02:42:34.9 |
HIP 96774 |
33.94 |
| 2026-05-24 00:00 |
19:42:20.89 |
+02:43:08.2 |
HIP 96774 |
32.98 |
| 2026-05-24 12:00 |
19:42:17.50 |
+02:43:41.1 |
HIP 96774 |
32.02 |
| 2026-05-25 00:00 |
19:42:14.07 |
+02:44:13.8 |
HIP 96774 |
31.04 |
| 2026-05-25 12:00 |
19:42:10.59 |
+02:44:46.1 |
HIP 96774 |
30.06 |
| 2026-05-26 00:00 |
19:42:07.07 |
+02:45:18.1 |
HIP 96774 |
29.08 |
| 2026-05-26 12:00 |
19:42:03.50 |
+02:45:49.8 |
HIP 96774 |
28.08 |
| 2026-05-27 00:00 |
19:41:59.88 |
+02:46:21.1 |
HIP 96774 |
27.08 |
| 2026-05-27 12:00 |
19:41:56.21 |
+02:46:52.1 |
HIP 96774 |
26.08 |
| 2026-05-28 00:00 |
19:41:52.50 |
+02:47:22.7 |
HIP 96774 |
25.06 |
| 2026-05-28 12:00 |
19:41:48.75 |
+02:47:53.0 |
HIP 96774 |
24.04 |
| 2026-05-29 00:00 |
19:41:44.95 |
+02:48:23.0 |
HIP 96774 |
23.01 |
| 2026-05-29 12:00 |
19:41:41.10 |
+02:48:52.6 |
HIP 96774 |
21.98 |
| 2026-05-30 00:00 |
19:41:37.21 |
+02:49:21.8 |
HIP 96774 |
20.95 |
| 2026-05-30 12:00 |
19:41:33.27 |
+02:49:50.8 |
HIP 96774 |
19.90 |
| 2026-05-31 00:00 |
19:41:29.30 |
+02:50:19.3 |
HIP 96774 |
18.86 |
| 2026-05-31 12:00 |
19:41:25.27 |
+02:50:47.5 |
HIP 96774 |
17.81 |
| 2026-06-01 00:00 |
19:41:21.21 |
+02:51:15.4 |
HIP 96774 |
16.76 |
| 2026-06-01 12:00 |
19:41:17.10 |
+02:51:42.9 |
HIP 96774 |
15.70 |
| 2026-06-02 00:00 |
19:41:12.95 |
+02:52:10.1 |
HIP 96774 |
14.65 |