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) |
| 2026-05-12 00:00 |
09:17:07.50 |
-87:54:13.8 |
HIP 46043 |
5.40 |
| 2026-05-12 12:00 |
09:17:10.26 |
-87:52:53.7 |
HIP 46043 |
6.49 |
| 2026-05-13 00:00 |
09:17:14.24 |
-87:51:33.6 |
HIP 46043 |
7.65 |
| 2026-05-13 12:00 |
09:17:19.40 |
-87:50:13.6 |
HIP 46043 |
8.86 |
| 2026-05-14 00:00 |
09:17:25.71 |
-87:48:53.5 |
HIP 46043 |
10.10 |
| 2026-05-14 12:00 |
09:17:33.12 |
-87:47:33.5 |
HIP 46043 |
11.35 |
| 2026-05-15 00:00 |
09:17:41.62 |
-87:46:13.5 |
HIP 46043 |
12.62 |
| 2026-05-15 12:00 |
09:17:51.15 |
-87:44:53.5 |
HIP 46043 |
13.90 |
| 2026-05-16 00:00 |
09:18:01.70 |
-87:43:33.6 |
HIP 46043 |
15.18 |
| 2026-05-16 12:00 |
09:18:13.23 |
-87:42:13.7 |
HIP 46043 |
16.47 |
| 2026-05-17 00:00 |
09:18:25.71 |
-87:40:53.8 |
HIP 46043 |
17.77 |
| 2026-05-17 12:00 |
09:18:39.12 |
-87:39:34.0 |
HIP 46043 |
19.06 |
| 2026-05-18 00:00 |
09:18:53.42 |
-87:38:14.3 |
HIP 46043 |
20.36 |
| 2026-05-18 12:00 |
09:19:08.59 |
-87:36:54.6 |
HIP 46043 |
21.67 |
| 2026-05-19 00:00 |
09:19:24.60 |
-87:35:35.0 |
HIP 46512 |
22.37 |
| 2026-05-19 12:00 |
09:19:41.42 |
-87:34:15.4 |
HIP 46512 |
21.06 |
| 2026-05-20 00:00 |
09:19:59.04 |
-87:32:55.9 |
HIP 46512 |
19.75 |
| 2026-05-20 12:00 |
09:20:17.43 |
-87:31:36.6 |
HIP 46512 |
18.44 |
| 2026-05-21 00:00 |
09:20:36.57 |
-87:30:17.3 |
HIP 46512 |
17.13 |
| 2026-05-21 12:00 |
09:20:56.43 |
-87:28:58.0 |
HIP 46512 |
15.82 |
| 2026-05-22 00:00 |
09:21:17.00 |
-87:27:38.9 |
HIP 46512 |
14.52 |
| 2026-05-22 12:00 |
09:21:38.25 |
-87:26:19.9 |
HIP 46512 |
13.22 |
| 2026-05-23 00:00 |
09:22:00.16 |
-87:25:01.0 |
HIP 46512 |
11.92 |
| 2026-05-23 12:00 |
09:22:22.71 |
-87:23:42.2 |
HIP 46512 |
10.63 |
| 2026-05-24 00:00 |
09:22:45.89 |
-87:22:23.4 |
HIP 46512 |
9.36 |
| 2026-05-24 12:00 |
09:23:09.68 |
-87:21:04.8 |
HIP 46512 |
8.10 |
| 2026-05-25 00:00 |
09:23:34.06 |
-87:19:46.4 |
HIP 46512 |
6.86 |
| 2026-05-25 12:00 |
09:23:59.02 |
-87:18:28.0 |
HIP 46512 |
5.66 |
| 2026-05-26 00:00 |
09:24:24.53 |
-87:17:09.7 |
HIP 46512 |
4.54 |
| 2026-05-26 12:00 |
09:24:50.59 |
-87:15:51.6 |
HIP 46512 |
3.55 |
| 2026-05-27 00:00 |
09:25:17.17 |
-87:14:33.6 |
HIP 46512 |
2.86 |
| 2026-05-27 12:00 |
09:25:44.28 |
-87:13:15.8 |
HIP 46512 |
2.70 |
| 2026-05-28 00:00 |
09:26:11.88 |
-87:11:58.0 |
HIP 46512 |
3.15 |
| 2026-05-28 12:00 |
09:26:39.97 |
-87:10:40.4 |
HIP 46512 |
4.00 |
| 2026-05-29 00:00 |
09:27:08.53 |
-87:09:23.0 |
HIP 45816 |
4.97 |
| 2026-05-29 12:00 |
09:27:37.56 |
-87:08:05.6 |
HIP 45816 |
5.64 |
| 2026-05-30 00:00 |
09:28:07.04 |
-87:06:48.5 |
HIP 45816 |
6.53 |
| 2026-05-30 12:00 |
09:28:36.96 |
-87:05:31.4 |
HIP 45816 |
7.56 |
| 2026-05-31 00:00 |
09:29:07.31 |
-87:04:14.5 |
HIP 45816 |
8.68 |
| 2026-05-31 12:00 |
09:29:38.08 |
-87:02:57.8 |
HIP 45816 |
9.86 |
| 2026-06-01 00:00 |
09:30:09.25 |
-87:01:41.2 |
HIP 45816 |
11.08 |
| 2026-06-01 12:00 |
09:30:40.82 |
-87:00:24.8 |
HIP 45816 |
12.33 |
| 2026-06-02 00:00 |
09:31:12.79 |
-86:59:08.5 |
HIP 45816 |
13.60 |