メタデータ
| 項目 |
値 |
| Designation |
C/2025 F2 (SWAN) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2025-05-01T03:51:29.594880Z |
| Orbit solution date (soln_date, UTC) |
2025-09-30T14:13:43Z |
| Obs used |
375 |
| NEO |
- |
| M1 |
12.300 |
| K1 |
13.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2025-03-22T12:00:00Z |
| Discovery magnitude (MPC) |
- |
| Discovery observatory (MPC) |
249 · SOHO |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2025-03-31.0000000 |
| e |
1.00013474 |
| q (au) |
0.333496 |
| a (au) |
-2475.174637 |
| i (deg) |
90.364801 |
| Ω (om, deg) |
329.839874 |
| ω (w, deg) |
153.835634 |
| M (ma, deg) |
-0.000249 |
等級
散乱 + 全体線形
$$
M_a = (12.159 + 3.735\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
12.159 |
| n |
3.735 |
| gf |
0.800 |
| gb |
-0.536 |
| k |
0.800 |
| δ90 |
9.999 |
| 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 |
| 2024-09-03 |
2025-04-05 |
+5.8025 |
+0.079 |
| 2025-04-05 |
2025-04-21 |
-13.4640 |
-2.999 |
| 2025-04-21 |
2025-04-29 |
-20.8594 |
-6.023 |
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 |
00:31:53.18 |
-51:25:39.1 |
HIP 2462 |
14.48 |
| 2026-03-26 12:00 |
00:32:21.29 |
-51:23:59.6 |
HIP 2462 |
18.04 |
| 2026-03-27 00:00 |
00:32:49.36 |
-51:22:22.1 |
HIP 2462 |
22.00 |
| 2026-03-27 12:00 |
00:33:17.38 |
-51:20:46.4 |
HIP 2462 |
26.17 |
| 2026-03-28 00:00 |
00:33:45.34 |
-51:19:12.7 |
HIP 2462 |
30.45 |
| 2026-03-28 12:00 |
00:34:13.25 |
-51:17:40.9 |
HIP 2462 |
34.79 |
| 2026-03-29 00:00 |
00:34:41.11 |
-51:16:11.0 |
HIP 2462 |
39.17 |
| 2026-03-29 12:00 |
00:35:08.92 |
-51:14:43.1 |
HIP 2993 |
41.07 |
| 2026-03-30 00:00 |
00:35:36.68 |
-51:13:17.1 |
HIP 2993 |
37.17 |
| 2026-03-30 12:00 |
00:36:04.38 |
-51:11:53.0 |
HIP 2993 |
33.47 |
| 2026-03-31 00:00 |
00:36:32.03 |
-51:10:30.8 |
HIP 2993 |
30.06 |
| 2026-03-31 12:00 |
00:36:59.62 |
-51:09:10.6 |
HIP 2993 |
27.01 |
| 2026-04-01 00:00 |
00:37:27.16 |
-51:07:52.3 |
HIP 2993 |
24.47 |
| 2026-04-01 12:00 |
00:37:54.64 |
-51:06:36.0 |
HIP 2993 |
22.60 |
| 2026-04-02 00:00 |
00:38:22.07 |
-51:05:21.6 |
HIP 2993 |
21.55 |
| 2026-04-02 12:00 |
00:38:49.44 |
-51:04:09.1 |
HIP 2993 |
21.44 |
| 2026-04-03 00:00 |
00:39:16.75 |
-51:02:58.5 |
HIP 2993 |
22.27 |
| 2026-04-03 12:00 |
00:39:44.01 |
-51:01:49.9 |
HIP 3213 |
23.53 |
| 2026-04-04 00:00 |
00:40:11.21 |
-51:00:43.2 |
HIP 3213 |
22.99 |
| 2026-04-04 12:00 |
00:40:38.35 |
-50:59:38.5 |
HIP 3213 |
23.25 |
| 2026-04-05 00:00 |
00:41:05.43 |
-50:58:35.7 |
HIP 3422 |
23.68 |
| 2026-04-05 12:00 |
00:41:32.46 |
-50:57:34.8 |
HIP 3422 |
19.46 |
| 2026-04-06 00:00 |
00:41:59.42 |
-50:56:35.9 |
HIP 3422 |
15.32 |
| 2026-04-06 12:00 |
00:42:26.32 |
-50:55:39.0 |
HIP 3422 |
11.34 |
| 2026-04-07 00:00 |
00:42:53.17 |
-50:54:44.0 |
HIP 3422 |
7.76 |
| 2026-04-07 12:00 |
00:43:19.95 |
-50:53:50.9 |
HIP 3422 |
5.37 |
| 2026-04-08 00:00 |
00:43:46.67 |
-50:52:59.8 |
HIP 3422 |
5.85 |
| 2026-04-08 12:00 |
00:44:13.32 |
-50:52:10.7 |
HIP 3422 |
8.72 |
| 2026-04-09 00:00 |
00:44:39.92 |
-50:51:23.5 |
HIP 3422 |
12.40 |
| 2026-04-09 12:00 |
00:45:06.45 |
-50:50:38.3 |
HIP 3547 |
13.19 |
| 2026-04-10 00:00 |
00:45:32.91 |
-50:49:55.0 |
HIP 3644 |
10.80 |
| 2026-04-10 12:00 |
00:45:59.31 |
-50:49:13.7 |
HIP 3644 |
6.58 |
| 2026-04-11 00:00 |
00:46:25.65 |
-50:48:34.4 |
HIP 3644 |
2.37 |
| 2026-04-11 12:00 |
00:46:51.92 |
-50:47:57.0 |
HIP 3644 |
1.84 |
| 2026-04-12 00:00 |
00:47:18.12 |
-50:47:21.7 |
HIP 3644 |
6.02 |
| 2026-04-12 12:00 |
00:47:44.25 |
-50:46:48.3 |
HIP 3644 |
10.18 |
| 2026-04-13 00:00 |
00:48:10.32 |
-50:46:16.8 |
HIP 3644 |
14.34 |
| 2026-04-13 12:00 |
00:48:36.31 |
-50:45:47.4 |
HIP 3644 |
18.48 |
| 2026-04-14 00:00 |
00:49:02.24 |
-50:45:19.9 |
HIP 3949 |
20.88 |
| 2026-04-14 12:00 |
00:49:28.09 |
-50:44:54.5 |
HIP 3949 |
18.37 |
| 2026-04-15 00:00 |
00:49:53.88 |
-50:44:31.0 |
HIP 3949 |
16.48 |
| 2026-04-15 12:00 |
00:50:19.59 |
-50:44:09.5 |
HIP 3949 |
15.44 |
| 2026-04-16 00:00 |
00:50:45.22 |
-50:43:50.0 |
HIP 3949 |
15.40 |