メタデータ
| 項目 |
値 |
| Designation |
31P/Schwassmann-Wachmann 2 |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2010-09-29T11:16:57.953280Z |
| Orbit solution date (soln_date, UTC) |
2025-11-23T22:21:40Z |
| Obs used |
1028 |
| NEO |
- |
| M1 |
4.200 |
| K1 |
23.000 |
| PC |
0.030 |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2011-02-16.0000000 |
| e |
0.19303098 |
| q (au) |
3.424308 |
| a (au) |
4.243419 |
| i (deg) |
4.546365 |
| Ω (om, deg) |
114.186460 |
| ω (w, deg) |
17.932787 |
| M (ma, deg) |
15.732489 |
等級
散乱 + 全体線形
$$
M_a = (14.954 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
14.954 |
| n |
2.000 |
| gf |
0.962 |
| gb |
-0.501 |
| k |
1.000 |
| δ90 |
9.174 |
| 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) |
| 2026-03-26 00:00 |
01:32:58.11 |
+05:42:15.6 |
HIP 7220 |
19.34 |
| 2026-03-26 12:00 |
01:33:27.87 |
+05:45:18.8 |
HIP 7220 |
23.36 |
| 2026-03-27 00:00 |
01:33:57.67 |
+05:48:21.9 |
HIP 7220 |
29.09 |
| 2026-03-27 12:00 |
01:34:27.52 |
+05:51:25.0 |
HIP 7220 |
35.71 |
| 2026-03-28 00:00 |
01:34:57.41 |
+05:54:28.0 |
HIP 7454 |
32.57 |
| 2026-03-28 12:00 |
01:35:27.35 |
+05:57:30.9 |
HIP 7454 |
26.71 |
| 2026-03-29 00:00 |
01:35:57.33 |
+06:00:33.7 |
HIP 7454 |
22.25 |
| 2026-03-29 12:00 |
01:36:27.36 |
+06:03:36.5 |
HIP 7454 |
20.17 |
| 2026-03-30 00:00 |
01:36:57.42 |
+06:06:39.2 |
HIP 7454 |
21.18 |
| 2026-03-30 12:00 |
01:37:27.53 |
+06:09:41.8 |
HIP 7454 |
24.92 |
| 2026-03-31 00:00 |
01:37:57.68 |
+06:12:44.3 |
HIP 7454 |
30.41 |
| 2026-03-31 12:00 |
01:38:27.87 |
+06:15:46.6 |
HIP 7774 |
24.97 |
| 2026-04-01 00:00 |
01:38:58.11 |
+06:18:48.9 |
HIP 7774 |
16.91 |
| 2026-04-01 12:00 |
01:39:28.38 |
+06:21:51.1 |
HIP 7774 |
8.91 |
| 2026-04-02 00:00 |
01:39:58.69 |
+06:24:53.2 |
HIP 7774 |
2.14 |
| 2026-04-02 12:00 |
01:40:29.04 |
+06:27:55.2 |
HIP 7774 |
7.86 |
| 2026-04-03 00:00 |
01:40:59.43 |
+06:30:57.0 |
HIP 7774 |
15.85 |
| 2026-04-03 12:00 |
01:41:29.86 |
+06:33:58.7 |
HIP 7774 |
23.95 |
| 2026-04-04 00:00 |
01:42:00.33 |
+06:37:00.3 |
HIP 7774 |
32.07 |
| 2026-04-04 12:00 |
01:42:30.84 |
+06:40:01.8 |
HIP 8031 |
34.75 |
| 2026-04-05 00:00 |
01:43:01.38 |
+06:43:03.2 |
HIP 8120 |
29.54 |
| 2026-04-05 12:00 |
01:43:31.96 |
+06:46:04.4 |
HIP 8120 |
22.44 |
| 2026-04-06 00:00 |
01:44:02.57 |
+06:49:05.4 |
HIP 8120 |
16.36 |
| 2026-04-06 12:00 |
01:44:33.23 |
+06:52:06.3 |
HIP 8120 |
12.87 |
| 2026-04-07 00:00 |
01:45:03.91 |
+06:55:07.1 |
HIP 8120 |
14.06 |
| 2026-04-07 12:00 |
01:45:34.64 |
+06:58:07.7 |
HIP 8120 |
19.08 |
| 2026-04-08 00:00 |
01:46:05.39 |
+07:01:08.1 |
HIP 8319 |
17.82 |
| 2026-04-08 12:00 |
01:46:36.18 |
+07:04:08.4 |
HIP 8319 |
11.41 |
| 2026-04-09 00:00 |
01:47:07.01 |
+07:07:08.6 |
HIP 8319 |
8.79 |
| 2026-04-09 12:00 |
01:47:37.87 |
+07:10:08.5 |
HIP 8319 |
12.63 |
| 2026-04-10 00:00 |
01:48:08.76 |
+07:13:08.3 |
HIP 8319 |
19.42 |
| 2026-04-10 12:00 |
01:48:39.68 |
+07:16:07.9 |
HIP 8524 |
19.12 |
| 2026-04-11 00:00 |
01:49:10.64 |
+07:19:07.3 |
HIP 8524 |
12.61 |
| 2026-04-11 12:00 |
01:49:41.62 |
+07:22:06.5 |
HIP 8524 |
9.39 |
| 2026-04-12 00:00 |
01:50:12.64 |
+07:25:05.5 |
HIP 8524 |
12.38 |
| 2026-04-12 12:00 |
01:50:43.69 |
+07:28:04.4 |
HIP 8685 |
16.25 |
| 2026-04-13 00:00 |
01:51:14.76 |
+07:31:03.0 |
HIP 8685 |
8.01 |
| 2026-04-13 12:00 |
01:51:45.87 |
+07:34:01.4 |
HIP 8685 |
0.72 |
| 2026-04-14 00:00 |
01:52:17.01 |
+07:36:59.6 |
HIP 8685 |
8.58 |
| 2026-04-14 12:00 |
01:52:48.17 |
+07:39:57.6 |
HIP 8836 |
12.56 |
| 2026-04-15 00:00 |
01:53:19.36 |
+07:42:55.4 |
HIP 8836 |
6.77 |
| 2026-04-15 12:00 |
01:53:50.58 |
+07:45:52.9 |
HIP 8836 |
8.42 |
| 2026-04-16 00:00 |
01:54:21.82 |
+07:48:50.2 |
HIP 8836 |
15.27 |