メタデータ
| 項目 |
値 |
| Designation |
C/2015 X2 (Catalina) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-12-20T17:13:10.505280Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:18Z |
| Obs used |
43 |
| NEO |
- |
| M1 |
16.100 |
| K1 |
10.000 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2015-12-12.0000000 |
| e |
0.87907924 |
| q (au) |
1.904555 |
| a (au) |
15.750441 |
| i (deg) |
72.458476 |
| Ω (om, deg) |
101.094124 |
| ω (w, deg) |
42.018183 |
| M (ma, deg) |
359.862546 |
等級
散乱 + 全体線形
$$
M_a = (18.961 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
18.961 |
| n |
2.000 |
| 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) |
| 2026-07-29 00:00 |
19:28:23.27 |
-43:37:52.8 |
HIP 95741 |
9.76 |
| 2026-07-29 12:00 |
19:28:15.72 |
-43:38:03.1 |
HIP 95741 |
10.08 |
| 2026-07-30 00:00 |
19:28:08.20 |
-43:38:13.1 |
HIP 95741 |
10.57 |
| 2026-07-30 12:00 |
19:28:00.69 |
-43:38:22.8 |
HIP 95741 |
11.20 |
| 2026-07-31 00:00 |
19:27:53.21 |
-43:38:32.1 |
HIP 95741 |
11.94 |
| 2026-07-31 12:00 |
19:27:45.75 |
-43:38:41.1 |
HIP 95741 |
12.78 |
| 2026-08-01 00:00 |
19:27:38.31 |
-43:38:49.8 |
HIP 95741 |
13.70 |
| 2026-08-01 12:00 |
19:27:30.90 |
-43:38:58.1 |
HIP 95741 |
14.68 |
| 2026-08-02 00:00 |
19:27:23.52 |
-43:39:06.1 |
HIP 95741 |
15.70 |
| 2026-08-02 12:00 |
19:27:16.15 |
-43:39:13.7 |
HIP 95741 |
16.77 |
| 2026-08-03 00:00 |
19:27:08.82 |
-43:39:21.0 |
HIP 95741 |
17.86 |
| 2026-08-03 12:00 |
19:27:01.51 |
-43:39:28.0 |
HIP 95741 |
18.98 |
| 2026-08-04 00:00 |
19:26:54.23 |
-43:39:34.7 |
HIP 95741 |
20.12 |
| 2026-08-04 12:00 |
19:26:46.98 |
-43:39:41.0 |
HIP 95741 |
21.27 |
| 2026-08-05 00:00 |
19:26:39.75 |
-43:39:47.0 |
HIP 95741 |
22.43 |
| 2026-08-05 12:00 |
19:26:32.56 |
-43:39:52.6 |
HIP 95741 |
23.60 |
| 2026-08-06 00:00 |
19:26:25.39 |
-43:39:57.9 |
HIP 95396 |
22.65 |
| 2026-08-06 12:00 |
19:26:18.26 |
-43:40:02.9 |
HIP 95396 |
21.37 |
| 2026-08-07 00:00 |
19:26:11.15 |
-43:40:07.6 |
HIP 95396 |
20.08 |
| 2026-08-07 12:00 |
19:26:04.08 |
-43:40:11.9 |
HIP 95396 |
18.81 |
| 2026-08-08 00:00 |
19:25:57.04 |
-43:40:15.9 |
HIP 95396 |
17.55 |
| 2026-08-08 12:00 |
19:25:50.04 |
-43:40:19.5 |
HIP 95396 |
16.29 |
| 2026-08-09 00:00 |
19:25:43.06 |
-43:40:22.9 |
HIP 95396 |
15.04 |
| 2026-08-09 12:00 |
19:25:36.13 |
-43:40:25.9 |
HIP 95396 |
13.80 |
| 2026-08-10 00:00 |
19:25:29.22 |
-43:40:28.6 |
HIP 95396 |
12.58 |
| 2026-08-10 12:00 |
19:25:22.36 |
-43:40:30.9 |
HIP 95396 |
11.36 |
| 2026-08-11 00:00 |
19:25:15.52 |
-43:40:32.9 |
HIP 95396 |
10.16 |
| 2026-08-11 12:00 |
19:25:08.73 |
-43:40:34.6 |
HIP 95396 |
8.98 |
| 2026-08-12 00:00 |
19:25:01.97 |
-43:40:36.0 |
HIP 95396 |
7.81 |
| 2026-08-12 12:00 |
19:24:55.26 |
-43:40:37.1 |
HIP 95396 |
6.68 |
| 2026-08-13 00:00 |
19:24:48.58 |
-43:40:37.8 |
HIP 95396 |
5.59 |
| 2026-08-13 12:00 |
19:24:41.94 |
-43:40:38.2 |
HIP 95396 |
4.57 |
| 2026-08-14 00:00 |
19:24:35.34 |
-43:40:38.3 |
HIP 95396 |
3.67 |
| 2026-08-14 12:00 |
19:24:28.78 |
-43:40:38.1 |
HIP 95396 |
3.00 |
| 2026-08-15 00:00 |
19:24:22.26 |
-43:40:37.5 |
HIP 95396 |
2.70 |
| 2026-08-15 12:00 |
19:24:15.78 |
-43:40:36.6 |
HIP 95396 |
2.90 |
| 2026-08-16 00:00 |
19:24:09.35 |
-43:40:35.4 |
HIP 95396 |
3.50 |
| 2026-08-16 12:00 |
19:24:02.96 |
-43:40:34.0 |
HIP 95396 |
4.33 |
| 2026-08-17 00:00 |
19:23:56.61 |
-43:40:32.1 |
HIP 95396 |
5.29 |
| 2026-08-17 12:00 |
19:23:50.30 |
-43:40:30.0 |
HIP 95396 |
6.30 |
| 2026-08-18 00:00 |
19:23:44.04 |
-43:40:27.6 |
HIP 95396 |
7.34 |
| 2026-08-18 12:00 |
19:23:37.83 |
-43:40:24.9 |
HIP 95396 |
8.40 |
| 2026-08-19 00:00 |
19:23:31.66 |
-43:40:21.8 |
HIP 95396 |
9.47 |