メタデータ
| 項目 |
値 |
| Designation |
C/2012 X2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2013-03-31T07:31:18.105600Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:29Z |
| Obs used |
186 |
| NEO |
- |
| M1 |
12.600 |
| 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) |
2013-05-10.0000000 |
| e |
0.77049741 |
| q (au) |
4.748158 |
| a (au) |
20.688908 |
| i (deg) |
34.123911 |
| Ω (om, deg) |
271.023294 |
| ω (w, deg) |
215.631135 |
| M (ma, deg) |
0.415663 |
等級
散乱 + 全体線形
$$
M_a = (10.863 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
10.863 |
| n |
2.000 |
| gf |
0.969 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
9.860 |
| 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 |
| 2012-01-11 |
2013-03-14 |
+4.8190 |
-2.841 |
| 2013-03-31 |
2014-04-24 |
-8.5260 |
+5.540 |
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) |
| 2026-09-20 00:00 |
17:51:44.21 |
-23:38:05.1 |
HIP 87399 |
2.81 |
| 2026-09-20 12:00 |
17:51:44.87 |
-23:37:59.0 |
HIP 87399 |
2.97 |
| 2026-09-21 00:00 |
17:51:45.57 |
-23:37:52.9 |
HIP 87399 |
3.13 |
| 2026-09-21 12:00 |
17:51:46.33 |
-23:37:46.9 |
HIP 87399 |
3.31 |
| 2026-09-22 00:00 |
17:51:47.13 |
-23:37:40.9 |
HIP 87399 |
3.49 |
| 2026-09-22 12:00 |
17:51:47.98 |
-23:37:34.8 |
HIP 87399 |
3.68 |
| 2026-09-23 00:00 |
17:51:48.88 |
-23:37:28.8 |
HIP 87399 |
3.87 |
| 2026-09-23 12:00 |
17:51:49.83 |
-23:37:22.8 |
HIP 87399 |
4.08 |
| 2026-09-24 00:00 |
17:51:50.83 |
-23:37:16.9 |
HIP 87399 |
4.30 |
| 2026-09-24 12:00 |
17:51:51.87 |
-23:37:10.9 |
HIP 87399 |
4.53 |
| 2026-09-25 00:00 |
17:51:52.97 |
-23:37:05.0 |
HIP 87399 |
4.77 |
| 2026-09-25 12:00 |
17:51:54.11 |
-23:36:59.0 |
HIP 87399 |
5.02 |
| 2026-09-26 00:00 |
17:51:55.30 |
-23:36:53.1 |
HIP 87399 |
5.28 |
| 2026-09-26 12:00 |
17:51:56.54 |
-23:36:47.2 |
HIP 87399 |
5.55 |
| 2026-09-27 00:00 |
17:51:57.83 |
-23:36:41.3 |
HIP 87399 |
5.83 |
| 2026-09-27 12:00 |
17:51:59.17 |
-23:36:35.5 |
HIP 87399 |
6.13 |
| 2026-09-28 00:00 |
17:52:00.55 |
-23:36:29.6 |
HIP 87399 |
6.43 |
| 2026-09-28 12:00 |
17:52:01.99 |
-23:36:23.7 |
HIP 87399 |
6.74 |
| 2026-09-29 00:00 |
17:52:03.47 |
-23:36:17.9 |
HIP 87399 |
7.07 |
| 2026-09-29 12:00 |
17:52:04.99 |
-23:36:12.1 |
HIP 87399 |
7.41 |
| 2026-09-30 00:00 |
17:52:06.57 |
-23:36:06.3 |
HIP 87399 |
7.75 |
| 2026-09-30 12:00 |
17:52:08.19 |
-23:36:00.5 |
HIP 87399 |
8.11 |
| 2026-10-01 00:00 |
17:52:09.86 |
-23:35:54.7 |
HIP 87399 |
8.48 |
| 2026-10-01 12:00 |
17:52:11.58 |
-23:35:49.0 |
HIP 87399 |
8.87 |
| 2026-10-02 00:00 |
17:52:13.34 |
-23:35:43.2 |
HIP 87399 |
9.26 |
| 2026-10-02 12:00 |
17:52:15.16 |
-23:35:37.5 |
HIP 87399 |
9.66 |
| 2026-10-03 00:00 |
17:52:17.02 |
-23:35:31.8 |
HIP 87399 |
10.07 |
| 2026-10-03 12:00 |
17:52:18.92 |
-23:35:26.1 |
HIP 87399 |
10.50 |
| 2026-10-04 00:00 |
17:52:20.88 |
-23:35:20.4 |
HIP 87399 |
10.94 |
| 2026-10-04 12:00 |
17:52:22.88 |
-23:35:14.7 |
HIP 87399 |
11.38 |
| 2026-10-05 00:00 |
17:52:24.92 |
-23:35:09.0 |
HIP 87399 |
11.84 |
| 2026-10-05 12:00 |
17:52:27.02 |
-23:35:03.4 |
HIP 87399 |
12.31 |
| 2026-10-06 00:00 |
17:52:29.16 |
-23:34:57.7 |
HIP 87399 |
12.79 |
| 2026-10-06 12:00 |
17:52:31.34 |
-23:34:52.1 |
HIP 87399 |
13.28 |
| 2026-10-07 00:00 |
17:52:33.57 |
-23:34:46.5 |
HIP 87399 |
13.79 |
| 2026-10-07 12:00 |
17:52:35.85 |
-23:34:40.8 |
HIP 87399 |
14.30 |
| 2026-10-08 00:00 |
17:52:38.18 |
-23:34:35.2 |
HIP 87399 |
14.82 |
| 2026-10-08 12:00 |
17:52:40.55 |
-23:34:29.7 |
HIP 87399 |
15.36 |
| 2026-10-09 00:00 |
17:52:42.97 |
-23:34:24.1 |
HIP 87399 |
15.90 |
| 2026-10-09 12:00 |
17:52:45.43 |
-23:34:18.5 |
HIP 87399 |
16.46 |
| 2026-10-10 00:00 |
17:52:47.94 |
-23:34:13.0 |
HIP 87399 |
17.02 |
| 2026-10-10 12:00 |
17:52:50.49 |
-23:34:07.4 |
HIP 87399 |
17.60 |
| 2026-10-11 00:00 |
17:52:53.09 |
-23:34:01.9 |
HIP 87399 |
18.19 |