メタデータ
| 項目 |
値 |
| Designation |
C/2025 K4 (Siverd) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2025-07-28T06:25:56.997120Z |
| Orbit solution date (soln_date, UTC) |
2025-12-12T11:12:30Z |
| Obs used |
29 |
| NEO |
- |
| M1 |
13.800 |
| K1 |
10.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2025-05-30T22:52:21.100800Z |
| Discovery magnitude (MPC) |
19.15 o |
| Discovery observatory (MPC) |
M22 · ATLAS South Africa, Sutherland |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2025-06-16.0000000 |
| e |
0.94157044 |
| q (au) |
2.532201 |
| a (au) |
43.337668 |
| i (deg) |
38.543416 |
| Ω (om, deg) |
297.083175 |
| ω (w, deg) |
326.935879 |
| M (ma, deg) |
359.853978 |
等級
散乱 + 全体線形
$$
M_a = (10.661 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
10.661 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.502 |
| 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
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
22:31:03.81 |
+14:09:54.2 |
HIP 111301 |
25.94 |
| 2026-05-12 12:00 |
22:31:19.19 |
+14:16:14.7 |
HIP 111301 |
22.51 |
| 2026-05-13 00:00 |
22:31:34.37 |
+14:22:34.9 |
HIP 111301 |
21.24 |
| 2026-05-13 12:00 |
22:31:49.37 |
+14:28:54.8 |
HIP 111301 |
22.44 |
| 2026-05-14 00:00 |
22:32:04.18 |
+14:35:14.3 |
HIP 111301 |
25.76 |
| 2026-05-14 12:00 |
22:32:18.80 |
+14:41:33.4 |
HIP 111301 |
30.50 |
| 2026-05-15 00:00 |
22:32:33.22 |
+14:47:52.2 |
HIP 111417 |
30.30 |
| 2026-05-15 12:00 |
22:32:47.46 |
+14:54:10.5 |
HIP 111417 |
24.45 |
| 2026-05-16 00:00 |
22:33:01.50 |
+15:00:28.5 |
HIP 111417 |
19.55 |
| 2026-05-16 12:00 |
22:33:15.36 |
+15:06:46.1 |
HIP 111417 |
16.46 |
| 2026-05-17 00:00 |
22:33:29.01 |
+15:13:03.2 |
HIP 111417 |
16.19 |
| 2026-05-17 12:00 |
22:33:42.47 |
+15:19:19.9 |
HIP 111417 |
18.84 |
| 2026-05-18 00:00 |
22:33:55.74 |
+15:25:36.2 |
HIP 111435 |
18.59 |
| 2026-05-18 12:00 |
22:34:08.81 |
+15:31:52.0 |
HIP 111435 |
11.59 |
| 2026-05-19 00:00 |
22:34:21.68 |
+15:38:07.4 |
HIP 111435 |
4.63 |
| 2026-05-19 12:00 |
22:34:34.35 |
+15:44:22.3 |
HIP 111435 |
2.46 |
| 2026-05-20 00:00 |
22:34:46.82 |
+15:50:36.7 |
HIP 111435 |
9.32 |
| 2026-05-20 12:00 |
22:34:59.09 |
+15:56:50.6 |
HIP 111437 |
9.26 |
| 2026-05-21 00:00 |
22:35:11.17 |
+16:03:04.0 |
HIP 111437 |
9.21 |
| 2026-05-21 12:00 |
22:35:23.04 |
+16:09:16.9 |
HIP 111437 |
13.30 |
| 2026-05-22 00:00 |
22:35:34.70 |
+16:15:29.3 |
HIP 111437 |
19.00 |
| 2026-05-22 12:00 |
22:35:46.17 |
+16:21:41.2 |
HIP 111470 |
22.01 |
| 2026-05-23 00:00 |
22:35:57.43 |
+16:27:52.6 |
HIP 111470 |
18.77 |
| 2026-05-23 12:00 |
22:36:08.49 |
+16:34:03.4 |
HIP 111470 |
17.60 |
| 2026-05-24 00:00 |
22:36:19.34 |
+16:40:13.6 |
HIP 111470 |
18.86 |
| 2026-05-24 12:00 |
22:36:29.98 |
+16:46:23.3 |
HIP 111470 |
22.11 |
| 2026-05-25 00:00 |
22:36:40.42 |
+16:52:32.4 |
HIP 111658 |
25.45 |
| 2026-05-25 12:00 |
22:36:50.66 |
+16:58:40.9 |
HIP 111658 |
18.87 |
| 2026-05-26 00:00 |
22:37:00.68 |
+17:04:48.8 |
HIP 111658 |
12.37 |
| 2026-05-26 12:00 |
22:37:10.50 |
+17:10:56.2 |
HIP 111658 |
6.03 |
| 2026-05-27 00:00 |
22:37:20.10 |
+17:17:02.9 |
HIP 111658 |
2.36 |
| 2026-05-27 12:00 |
22:37:29.50 |
+17:23:09.0 |
HIP 111658 |
7.70 |
| 2026-05-28 00:00 |
22:37:38.69 |
+17:29:14.4 |
HIP 111658 |
14.02 |
| 2026-05-28 12:00 |
22:37:47.66 |
+17:35:19.2 |
HIP 111745 |
14.84 |
| 2026-05-29 00:00 |
22:37:56.43 |
+17:41:23.4 |
HIP 111745 |
8.43 |
| 2026-05-29 12:00 |
22:38:04.98 |
+17:47:26.9 |
HIP 111745 |
2.08 |
| 2026-05-30 00:00 |
22:38:13.31 |
+17:53:29.8 |
HIP 111745 |
4.38 |
| 2026-05-30 12:00 |
22:38:21.44 |
+17:59:31.9 |
HIP 111745 |
10.70 |
| 2026-05-31 00:00 |
22:38:29.34 |
+18:05:33.4 |
HIP 111745 |
17.01 |
| 2026-05-31 12:00 |
22:38:37.04 |
+18:11:34.1 |
HIP 111745 |
23.29 |
| 2026-06-01 00:00 |
22:38:44.51 |
+18:17:34.1 |
HIP 111745 |
29.55 |
| 2026-06-01 12:00 |
22:38:51.77 |
+18:23:33.4 |
HIP 111745 |
35.78 |
| 2026-06-02 00:00 |
22:38:58.81 |
+18:29:32.0 |
HIP 111981 |
38.86 |