メタデータ
| 項目 |
値 |
| Designation |
C/1967 Y1 (Ikeya-Seki) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1968-02-25T16:56:06.803520Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:17Z |
| Obs used |
197 |
| NEO |
- |
| M1 |
6.400 |
| 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) |
1968-03-18.0000000 |
| e |
0.99915636 |
| q (au) |
1.696579 |
| a (au) |
2011.021687 |
| i (deg) |
129.315339 |
| Ω (om, deg) |
255.321380 |
| ω (w, deg) |
70.864407 |
| M (ma, deg) |
0.000233 |
等級
散乱 + 全体線形
$$
M_a = (2.937 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
2.937 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.991 |
| 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) |
| 2026-09-20 00:00 |
03:02:02.59 |
-24:10:53.2 |
HIP 14072 |
14.03 |
| 2026-09-20 12:00 |
03:02:01.60 |
-24:11:07.4 |
HIP 14072 |
14.05 |
| 2026-09-21 00:00 |
03:02:00.60 |
-24:11:21.5 |
HIP 14072 |
14.07 |
| 2026-09-21 12:00 |
03:01:59.59 |
-24:11:35.6 |
HIP 14072 |
14.10 |
| 2026-09-22 00:00 |
03:01:58.57 |
-24:11:49.7 |
HIP 14072 |
14.13 |
| 2026-09-22 12:00 |
03:01:57.54 |
-24:12:03.7 |
HIP 14072 |
14.17 |
| 2026-09-23 00:00 |
03:01:56.49 |
-24:12:17.6 |
HIP 14072 |
14.22 |
| 2026-09-23 12:00 |
03:01:55.44 |
-24:12:31.5 |
HIP 14072 |
14.27 |
| 2026-09-24 00:00 |
03:01:54.38 |
-24:12:45.4 |
HIP 14072 |
14.33 |
| 2026-09-24 12:00 |
03:01:53.31 |
-24:12:59.2 |
HIP 14072 |
14.39 |
| 2026-09-25 00:00 |
03:01:52.24 |
-24:13:12.9 |
HIP 14072 |
14.46 |
| 2026-09-25 12:00 |
03:01:51.15 |
-24:13:26.6 |
HIP 14072 |
14.53 |
| 2026-09-26 00:00 |
03:01:50.05 |
-24:13:40.2 |
HIP 14072 |
14.61 |
| 2026-09-26 12:00 |
03:01:48.94 |
-24:13:53.8 |
HIP 14072 |
14.69 |
| 2026-09-27 00:00 |
03:01:47.83 |
-24:14:07.3 |
HIP 14072 |
14.78 |
| 2026-09-27 12:00 |
03:01:46.70 |
-24:14:20.8 |
HIP 14072 |
14.88 |
| 2026-09-28 00:00 |
03:01:45.57 |
-24:14:34.1 |
HIP 14072 |
14.98 |
| 2026-09-28 12:00 |
03:01:44.42 |
-24:14:47.5 |
HIP 14072 |
15.09 |
| 2026-09-29 00:00 |
03:01:43.27 |
-24:15:00.7 |
HIP 14072 |
15.20 |
| 2026-09-29 12:00 |
03:01:42.11 |
-24:15:13.9 |
HIP 14072 |
15.31 |
| 2026-09-30 00:00 |
03:01:40.94 |
-24:15:27.1 |
HIP 14072 |
15.44 |
| 2026-09-30 12:00 |
03:01:39.76 |
-24:15:40.1 |
HIP 14072 |
15.56 |
| 2026-10-01 00:00 |
03:01:38.57 |
-24:15:53.2 |
HIP 14072 |
15.70 |
| 2026-10-01 12:00 |
03:01:37.37 |
-24:16:06.1 |
HIP 14072 |
15.83 |
| 2026-10-02 00:00 |
03:01:36.17 |
-24:16:19.0 |
HIP 14072 |
15.98 |
| 2026-10-02 12:00 |
03:01:34.96 |
-24:16:31.8 |
HIP 14072 |
16.12 |
| 2026-10-03 00:00 |
03:01:33.74 |
-24:16:44.5 |
HIP 14072 |
16.27 |
| 2026-10-03 12:00 |
03:01:32.51 |
-24:16:57.1 |
HIP 14072 |
16.43 |
| 2026-10-04 00:00 |
03:01:31.27 |
-24:17:09.7 |
HIP 14072 |
16.59 |
| 2026-10-04 12:00 |
03:01:30.02 |
-24:17:22.2 |
HIP 14072 |
16.75 |
| 2026-10-05 00:00 |
03:01:28.77 |
-24:17:34.7 |
HIP 14072 |
16.92 |
| 2026-10-05 12:00 |
03:01:27.50 |
-24:17:47.0 |
HIP 14072 |
17.10 |
| 2026-10-06 00:00 |
03:01:26.24 |
-24:17:59.3 |
HIP 14072 |
17.27 |
| 2026-10-06 12:00 |
03:01:24.96 |
-24:18:11.5 |
HIP 14072 |
17.45 |
| 2026-10-07 00:00 |
03:01:23.67 |
-24:18:23.6 |
HIP 14072 |
17.64 |
| 2026-10-07 12:00 |
03:01:22.38 |
-24:18:35.7 |
HIP 14072 |
17.83 |
| 2026-10-08 00:00 |
03:01:21.08 |
-24:18:47.6 |
HIP 14072 |
18.02 |
| 2026-10-08 12:00 |
03:01:19.77 |
-24:18:59.5 |
HIP 14072 |
18.22 |
| 2026-10-09 00:00 |
03:01:18.46 |
-24:19:11.3 |
HIP 14072 |
18.42 |
| 2026-10-09 12:00 |
03:01:17.13 |
-24:19:23.0 |
HIP 14072 |
18.62 |
| 2026-10-10 00:00 |
03:01:15.80 |
-24:19:34.7 |
HIP 14072 |
18.83 |
| 2026-10-10 12:00 |
03:01:14.47 |
-24:19:46.2 |
HIP 14072 |
19.04 |
| 2026-10-11 00:00 |
03:01:13.12 |
-24:19:57.7 |
HIP 14072 |
19.25 |