メタデータ
| 項目 |
値 |
| Designation |
C/2017 O1 (ASASSN) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-10-14T18:50:39.171840Z |
| Orbit solution date (soln_date, UTC) |
2022-07-31T01:42:28Z |
| Obs used |
2877 |
| NEO |
- |
| M1 |
12.400 |
| K1 |
8.750 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2017-10-13.0000000 |
| e |
0.99642549 |
| q (au) |
1.498687 |
| a (au) |
419.270415 |
| i (deg) |
39.848413 |
| Ω (om, deg) |
25.809488 |
| ω (w, deg) |
20.907853 |
| M (ma, deg) |
359.999795 |
等級
散乱 + 全体線形
$$
M_a = (12.630 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
12.630 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.500 |
| 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
残差 (区間線形)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| 開始日 (UTC) |
終了日 (UTC) |
a |
b |
| 2017-07-20 |
2017-10-14 |
-12.1999 |
+1.263 |
| 2017-10-14 |
2019-03-12 |
+7.6667 |
-2.172 |
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) |
| 2026-09-20 00:00 |
13:15:22.83 |
-02:20:41.5 |
HIP 64569 |
33.95 |
| 2026-09-20 12:00 |
13:15:27.31 |
-02:21:15.3 |
HIP 64569 |
34.15 |
| 2026-09-21 00:00 |
13:15:31.81 |
-02:21:49.2 |
HIP 64569 |
34.41 |
| 2026-09-21 12:00 |
13:15:36.31 |
-02:22:23.1 |
HIP 64569 |
34.71 |
| 2026-09-22 00:00 |
13:15:40.84 |
-02:22:57.0 |
HIP 64569 |
35.05 |
| 2026-09-22 12:00 |
13:15:45.37 |
-02:23:30.9 |
HIP 64569 |
35.44 |
| 2026-09-23 00:00 |
13:15:49.92 |
-02:24:04.8 |
HIP 64569 |
35.87 |
| 2026-09-23 12:00 |
13:15:54.48 |
-02:24:38.8 |
HIP 64569 |
36.34 |
| 2026-09-24 00:00 |
13:15:59.05 |
-02:25:12.7 |
HIP 64569 |
36.86 |
| 2026-09-24 12:00 |
13:16:03.63 |
-02:25:46.7 |
HIP 64569 |
37.41 |
| 2026-09-25 00:00 |
13:16:08.23 |
-02:26:20.6 |
HIP 64569 |
37.99 |
| 2026-09-25 12:00 |
13:16:12.83 |
-02:26:54.6 |
HIP 64569 |
38.62 |
| 2026-09-26 00:00 |
13:16:17.45 |
-02:27:28.5 |
HIP 64569 |
39.27 |
| 2026-09-26 12:00 |
13:16:22.07 |
-02:28:02.5 |
HIP 64963 |
38.44 |
| 2026-09-27 00:00 |
13:16:26.71 |
-02:28:36.5 |
HIP 64963 |
37.24 |
| 2026-09-27 12:00 |
13:16:31.36 |
-02:29:10.4 |
HIP 64963 |
36.03 |
| 2026-09-28 00:00 |
13:16:36.01 |
-02:29:44.4 |
HIP 64963 |
34.83 |
| 2026-09-28 12:00 |
13:16:40.68 |
-02:30:18.3 |
HIP 64963 |
33.64 |
| 2026-09-29 00:00 |
13:16:45.35 |
-02:30:52.3 |
HIP 64963 |
32.45 |
| 2026-09-29 12:00 |
13:16:50.03 |
-02:31:26.2 |
HIP 64963 |
31.27 |
| 2026-09-30 00:00 |
13:16:54.73 |
-02:32:00.1 |
HIP 64963 |
30.09 |
| 2026-09-30 12:00 |
13:16:59.43 |
-02:32:34.0 |
HIP 64963 |
28.93 |
| 2026-10-01 00:00 |
13:17:04.14 |
-02:33:07.9 |
HIP 64963 |
27.77 |
| 2026-10-01 12:00 |
13:17:08.85 |
-02:33:41.8 |
HIP 64963 |
26.63 |
| 2026-10-02 00:00 |
13:17:13.58 |
-02:34:15.7 |
HIP 64963 |
25.49 |
| 2026-10-02 12:00 |
13:17:18.31 |
-02:34:49.5 |
HIP 64963 |
24.38 |
| 2026-10-03 00:00 |
13:17:23.05 |
-02:35:23.3 |
HIP 64963 |
23.28 |
| 2026-10-03 12:00 |
13:17:27.79 |
-02:35:57.1 |
HIP 64963 |
22.21 |
| 2026-10-04 00:00 |
13:17:32.54 |
-02:36:30.9 |
HIP 64963 |
21.16 |
| 2026-10-04 12:00 |
13:17:37.30 |
-02:37:04.7 |
HIP 64963 |
20.14 |
| 2026-10-05 00:00 |
13:17:42.06 |
-02:37:38.4 |
HIP 64963 |
19.15 |
| 2026-10-05 12:00 |
13:17:46.83 |
-02:38:12.1 |
HIP 64963 |
18.21 |
| 2026-10-06 00:00 |
13:17:51.61 |
-02:38:45.7 |
HIP 64963 |
17.31 |
| 2026-10-06 12:00 |
13:17:56.39 |
-02:39:19.3 |
HIP 64963 |
16.47 |
| 2026-10-07 00:00 |
13:18:01.17 |
-02:39:52.9 |
HIP 64963 |
15.69 |
| 2026-10-07 12:00 |
13:18:05.96 |
-02:40:26.5 |
HIP 64963 |
14.98 |
| 2026-10-08 00:00 |
13:18:10.75 |
-02:41:00.0 |
HIP 64963 |
14.36 |
| 2026-10-08 12:00 |
13:18:15.55 |
-02:41:33.4 |
HIP 64963 |
13.84 |
| 2026-10-09 00:00 |
13:18:20.35 |
-02:42:06.8 |
HIP 64963 |
13.43 |
| 2026-10-09 12:00 |
13:18:25.15 |
-02:42:40.2 |
HIP 64963 |
13.14 |
| 2026-10-10 00:00 |
13:18:29.96 |
-02:43:13.5 |
HIP 64963 |
12.97 |
| 2026-10-10 12:00 |
13:18:34.76 |
-02:43:46.8 |
HIP 64963 |
12.94 |
| 2026-10-11 00:00 |
13:18:39.57 |
-02:44:20.0 |
HIP 64963 |
13.04 |