メタデータ
| 項目 |
値 |
| Designation |
C/2017 C1 (NEOWISE) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-01-18T22:42:46.506240Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:29Z |
| Obs used |
60 |
| NEO |
- |
| M1 |
18.100 |
| K1 |
8.500 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2017-03-06.0000000 |
| e |
0.92781552 |
| q (au) |
1.501755 |
| a (au) |
20.804403 |
| i (deg) |
65.752241 |
| Ω (om, deg) |
357.457191 |
| ω (w, deg) |
110.204316 |
| M (ma, deg) |
0.478338 |
等級
散乱 + 全体線形
$$
M_a = (17.436 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
17.436 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.703 |
| k |
0.800 |
| 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) |
| 2026-03-26 00:00 |
14:09:18.05 |
-89:08:40.2 |
HIP 78866 |
25.23 |
| 2026-03-26 12:00 |
14:04:08.14 |
-89:09:22.1 |
HIP 78866 |
25.75 |
| 2026-03-27 00:00 |
13:58:48.24 |
-89:10:01.6 |
HIP 78866 |
26.34 |
| 2026-03-27 12:00 |
13:53:18.55 |
-89:10:38.8 |
HIP 78866 |
26.99 |
| 2026-03-28 00:00 |
13:47:39.35 |
-89:11:13.6 |
HIP 78866 |
27.70 |
| 2026-03-28 12:00 |
13:41:51.00 |
-89:11:45.8 |
HIP 78866 |
28.47 |
| 2026-03-29 00:00 |
13:35:53.91 |
-89:12:15.4 |
HIP 78866 |
29.29 |
| 2026-03-29 12:00 |
13:29:48.62 |
-89:12:42.3 |
HIP 54065 |
29.15 |
| 2026-03-30 00:00 |
13:23:35.72 |
-89:13:06.4 |
HIP 54065 |
27.81 |
| 2026-03-30 12:00 |
13:17:15.88 |
-89:13:27.6 |
HIP 54065 |
26.48 |
| 2026-03-31 00:00 |
13:10:49.88 |
-89:13:46.0 |
HIP 54065 |
25.14 |
| 2026-03-31 12:00 |
13:04:18.53 |
-89:14:01.4 |
HIP 54065 |
23.81 |
| 2026-04-01 00:00 |
12:57:42.75 |
-89:14:13.7 |
HIP 54065 |
22.48 |
| 2026-04-01 12:00 |
12:51:03.47 |
-89:14:23.0 |
HIP 54065 |
21.16 |
| 2026-04-02 00:00 |
12:44:21.71 |
-89:14:29.3 |
HIP 54065 |
19.84 |
| 2026-04-02 12:00 |
12:37:38.50 |
-89:14:32.4 |
HIP 54065 |
18.52 |
| 2026-04-03 00:00 |
12:30:54.88 |
-89:14:32.5 |
HIP 54065 |
17.21 |
| 2026-04-03 12:00 |
12:24:11.92 |
-89:14:29.4 |
HIP 54065 |
15.91 |
| 2026-04-04 00:00 |
12:17:30.66 |
-89:14:23.3 |
HIP 54065 |
14.61 |
| 2026-04-04 12:00 |
12:10:52.13 |
-89:14:14.1 |
HIP 54065 |
13.33 |
| 2026-04-05 00:00 |
12:04:17.33 |
-89:14:01.8 |
HIP 54065 |
12.06 |
| 2026-04-05 12:00 |
11:57:47.19 |
-89:13:46.6 |
HIP 54065 |
10.81 |
| 2026-04-06 00:00 |
11:51:22.59 |
-89:13:28.5 |
HIP 54065 |
9.59 |
| 2026-04-06 12:00 |
11:45:04.36 |
-89:13:07.4 |
HIP 54065 |
8.41 |
| 2026-04-07 00:00 |
11:38:53.22 |
-89:12:43.6 |
HIP 54065 |
7.29 |
| 2026-04-07 12:00 |
11:32:49.85 |
-89:12:17.0 |
HIP 54065 |
6.26 |
| 2026-04-08 00:00 |
11:26:54.81 |
-89:11:47.8 |
HIP 54065 |
5.37 |
| 2026-04-08 12:00 |
11:21:08.61 |
-89:11:16.0 |
HIP 54065 |
4.71 |
| 2026-04-09 00:00 |
11:15:31.66 |
-89:10:41.7 |
HIP 54065 |
4.39 |
| 2026-04-09 12:00 |
11:10:04.28 |
-89:10:05.0 |
HIP 54065 |
4.46 |
| 2026-04-10 00:00 |
11:04:46.74 |
-89:09:26.0 |
HIP 54065 |
4.92 |
| 2026-04-10 12:00 |
10:59:39.21 |
-89:08:44.8 |
HIP 54065 |
5.67 |
| 2026-04-11 00:00 |
10:54:41.82 |
-89:08:01.5 |
HIP 54065 |
6.61 |
| 2026-04-11 12:00 |
10:49:54.62 |
-89:07:16.2 |
HIP 54065 |
7.68 |
| 2026-04-12 00:00 |
10:45:17.60 |
-89:06:28.9 |
HIP 54065 |
8.82 |
| 2026-04-12 12:00 |
10:40:50.73 |
-89:05:39.8 |
HIP 54065 |
10.02 |
| 2026-04-13 00:00 |
10:36:33.90 |
-89:04:48.9 |
HIP 54065 |
11.25 |
| 2026-04-13 12:00 |
10:32:26.99 |
-89:03:56.3 |
HIP 54065 |
12.50 |
| 2026-04-14 00:00 |
10:28:29.84 |
-89:03:02.1 |
HIP 54065 |
13.77 |
| 2026-04-14 12:00 |
10:24:42.25 |
-89:02:06.4 |
HIP 54065 |
15.06 |
| 2026-04-15 00:00 |
10:21:04.02 |
-89:01:09.3 |
HIP 54065 |
16.35 |
| 2026-04-15 12:00 |
10:17:34.93 |
-89:00:10.8 |
HIP 54065 |
17.65 |
| 2026-04-16 00:00 |
10:14:14.72 |
-88:59:11.0 |
HIP 54065 |
18.96 |