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) |
| 2026-03-26 00:00 |
19:42:32.73 |
+01:11:57.9 |
HIP 96908 |
8.64 |
| 2026-03-26 12:00 |
19:42:35.96 |
+01:12:50.8 |
HIP 96908 |
9.58 |
| 2026-03-27 00:00 |
19:42:39.13 |
+01:13:43.7 |
HIP 96908 |
10.56 |
| 2026-03-27 12:00 |
19:42:42.26 |
+01:14:36.5 |
HIP 96908 |
11.56 |
| 2026-03-28 00:00 |
19:42:45.32 |
+01:15:29.4 |
HIP 96908 |
12.58 |
| 2026-03-28 12:00 |
19:42:48.34 |
+01:16:22.2 |
HIP 96908 |
13.61 |
| 2026-03-29 00:00 |
19:42:51.29 |
+01:17:15.1 |
HIP 96993 |
14.63 |
| 2026-03-29 12:00 |
19:42:54.20 |
+01:18:07.9 |
HIP 96993 |
13.78 |
| 2026-03-30 00:00 |
19:42:57.04 |
+01:19:00.7 |
HIP 96993 |
12.98 |
| 2026-03-30 12:00 |
19:42:59.84 |
+01:19:53.5 |
HIP 96993 |
12.23 |
| 2026-03-31 00:00 |
19:43:02.58 |
+01:20:46.3 |
HIP 96993 |
11.53 |
| 2026-03-31 12:00 |
19:43:05.26 |
+01:21:39.1 |
HIP 96993 |
10.90 |
| 2026-04-01 00:00 |
19:43:07.88 |
+01:22:31.8 |
HIP 96993 |
10.34 |
| 2026-04-01 12:00 |
19:43:10.45 |
+01:23:24.5 |
HIP 96993 |
9.87 |
| 2026-04-02 00:00 |
19:43:12.97 |
+01:24:17.2 |
HIP 96993 |
9.49 |
| 2026-04-02 12:00 |
19:43:15.43 |
+01:25:09.8 |
HIP 96993 |
9.22 |
| 2026-04-03 00:00 |
19:43:17.83 |
+01:26:02.4 |
HIP 96993 |
9.05 |
| 2026-04-03 12:00 |
19:43:20.18 |
+01:26:55.0 |
HIP 96993 |
8.99 |
| 2026-04-04 00:00 |
19:43:22.47 |
+01:27:47.5 |
HIP 96993 |
9.05 |
| 2026-04-04 12:00 |
19:43:24.70 |
+01:28:40.0 |
HIP 96993 |
9.21 |
| 2026-04-05 00:00 |
19:43:26.88 |
+01:29:32.4 |
HIP 96993 |
9.47 |
| 2026-04-05 12:00 |
19:43:29.00 |
+01:30:24.8 |
HIP 96993 |
9.82 |
| 2026-04-06 00:00 |
19:43:31.07 |
+01:31:17.1 |
HIP 96993 |
10.24 |
| 2026-04-06 12:00 |
19:43:33.07 |
+01:32:09.4 |
HIP 96993 |
10.73 |
| 2026-04-07 00:00 |
19:43:35.02 |
+01:33:01.6 |
HIP 96993 |
11.27 |
| 2026-04-07 12:00 |
19:43:36.92 |
+01:33:53.7 |
HIP 96993 |
11.86 |
| 2026-04-08 00:00 |
19:43:38.75 |
+01:34:45.8 |
HIP 96993 |
12.48 |
| 2026-04-08 12:00 |
19:43:40.53 |
+01:35:37.8 |
HIP 96993 |
13.14 |
| 2026-04-09 00:00 |
19:43:42.25 |
+01:36:29.8 |
HIP 96993 |
13.81 |
| 2026-04-09 12:00 |
19:43:43.91 |
+01:37:21.6 |
HIP 96993 |
14.51 |
| 2026-04-10 00:00 |
19:43:45.52 |
+01:38:13.4 |
HIP 96993 |
15.22 |
| 2026-04-10 12:00 |
19:43:47.06 |
+01:39:05.1 |
HIP 96993 |
15.94 |
| 2026-04-11 00:00 |
19:43:48.55 |
+01:39:56.8 |
HIP 96993 |
16.68 |
| 2026-04-11 12:00 |
19:43:49.98 |
+01:40:48.3 |
HIP 96993 |
17.41 |
| 2026-04-12 00:00 |
19:43:51.36 |
+01:41:39.7 |
HIP 96993 |
18.16 |
| 2026-04-12 12:00 |
19:43:52.67 |
+01:42:31.1 |
HIP 96993 |
18.90 |
| 2026-04-13 00:00 |
19:43:53.92 |
+01:43:22.3 |
HIP 96993 |
19.65 |
| 2026-04-13 12:00 |
19:43:55.12 |
+01:44:13.5 |
HIP 96993 |
20.40 |
| 2026-04-14 00:00 |
19:43:56.26 |
+01:45:04.5 |
HIP 96993 |
21.15 |
| 2026-04-14 12:00 |
19:43:57.34 |
+01:45:55.5 |
HIP 96993 |
21.89 |
| 2026-04-15 00:00 |
19:43:58.36 |
+01:46:46.3 |
HIP 96993 |
22.64 |
| 2026-04-15 12:00 |
19:43:59.32 |
+01:47:37.1 |
HIP 96993 |
23.38 |
| 2026-04-16 00:00 |
19:44:00.23 |
+01:48:27.7 |
HIP 96993 |
24.12 |