メタデータ
| 項目 |
値 |
| Designation |
C/2018 N1 (NEOWISE) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2018-08-01T23:35:12.114240Z |
| Orbit solution date (soln_date, UTC) |
2022-06-20T23:12:32Z |
| Obs used |
263 |
| NEO |
- |
| M1 |
14.800 |
| K1 |
11.750 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2018-07-02T08:53:36.384000Z |
| Discovery magnitude (MPC) |
16.00 R |
| Discovery observatory (MPC) |
C51 · WISE |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2018-07-23.0000000 |
| e |
0.99690168 |
| q (au) |
1.307382 |
| a (au) |
421.964782 |
| i (deg) |
159.444331 |
| Ω (om, deg) |
292.438182 |
| ω (w, deg) |
354.558421 |
| M (ma, deg) |
359.998865 |
等級
散乱 + 全体線形
$$
M_a = (13.856 + 5.455\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
13.856 |
| n |
5.455 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
0.957 |
| δ90 |
1.000 |
| 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 |
| 2017-12-15 |
2018-08-01 |
+5.8573 |
-2.511 |
| 2018-08-02 |
2018-10-06 |
-17.1024 |
-0.661 |
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 |
10:08:14.22 |
+23:01:32.3 |
HIP 49700 |
28.16 |
| 2026-09-20 12:00 |
10:08:18.52 |
+23:01:16.3 |
HIP 49700 |
28.19 |
| 2026-09-21 00:00 |
10:08:22.79 |
+23:01:00.5 |
HIP 49700 |
28.26 |
| 2026-09-21 12:00 |
10:08:27.04 |
+23:00:45.0 |
HIP 49700 |
28.36 |
| 2026-09-22 00:00 |
10:08:31.27 |
+23:00:29.7 |
HIP 49700 |
28.49 |
| 2026-09-22 12:00 |
10:08:35.48 |
+23:00:14.6 |
HIP 49700 |
28.66 |
| 2026-09-23 00:00 |
10:08:39.67 |
+22:59:59.8 |
HIP 49700 |
28.85 |
| 2026-09-23 12:00 |
10:08:43.84 |
+22:59:45.1 |
HIP 49700 |
29.08 |
| 2026-09-24 00:00 |
10:08:47.98 |
+22:59:30.7 |
HIP 49700 |
29.33 |
| 2026-09-24 12:00 |
10:08:52.10 |
+22:59:16.5 |
HIP 49700 |
29.61 |
| 2026-09-25 00:00 |
10:08:56.19 |
+22:59:02.6 |
HIP 49700 |
29.91 |
| 2026-09-25 12:00 |
10:09:00.27 |
+22:58:48.8 |
HIP 49700 |
30.24 |
| 2026-09-26 00:00 |
10:09:04.32 |
+22:58:35.3 |
HIP 49700 |
30.59 |
| 2026-09-26 12:00 |
10:09:08.34 |
+22:58:22.1 |
HIP 49700 |
30.96 |
| 2026-09-27 00:00 |
10:09:12.34 |
+22:58:09.0 |
HIP 49700 |
31.35 |
| 2026-09-27 12:00 |
10:09:16.32 |
+22:57:56.2 |
HIP 49700 |
31.75 |
| 2026-09-28 00:00 |
10:09:20.27 |
+22:57:43.7 |
HIP 49700 |
32.18 |
| 2026-09-28 12:00 |
10:09:24.20 |
+22:57:31.3 |
HIP 49700 |
32.62 |
| 2026-09-29 00:00 |
10:09:28.10 |
+22:57:19.2 |
HIP 49700 |
33.07 |
| 2026-09-29 12:00 |
10:09:31.98 |
+22:57:07.4 |
HIP 49700 |
33.54 |
| 2026-09-30 00:00 |
10:09:35.83 |
+22:56:55.8 |
HIP 49700 |
34.02 |
| 2026-09-30 12:00 |
10:09:39.65 |
+22:56:44.4 |
HIP 49700 |
34.51 |
| 2026-10-01 00:00 |
10:09:43.45 |
+22:56:33.3 |
HIP 49700 |
35.01 |
| 2026-10-01 12:00 |
10:09:47.22 |
+22:56:22.4 |
HIP 49700 |
35.53 |
| 2026-10-02 00:00 |
10:09:50.96 |
+22:56:11.7 |
HIP 49700 |
36.04 |
| 2026-10-02 12:00 |
10:09:54.67 |
+22:56:01.3 |
HIP 49700 |
36.57 |
| 2026-10-03 00:00 |
10:09:58.36 |
+22:55:51.1 |
HIP 49700 |
37.10 |
| 2026-10-03 12:00 |
10:10:02.02 |
+22:55:41.2 |
HIP 49700 |
37.64 |
| 2026-10-04 00:00 |
10:10:05.65 |
+22:55:31.6 |
HIP 49700 |
38.18 |
| 2026-10-04 12:00 |
10:10:09.26 |
+22:55:22.1 |
HIP 49700 |
38.73 |
| 2026-10-05 00:00 |
10:10:12.83 |
+22:55:13.0 |
HIP 49700 |
39.28 |
| 2026-10-05 12:00 |
10:10:16.37 |
+22:55:04.1 |
HIP 50048 |
38.99 |
| 2026-10-06 00:00 |
10:10:19.89 |
+22:54:55.4 |
HIP 50048 |
38.17 |
| 2026-10-06 12:00 |
10:10:23.37 |
+22:54:47.0 |
HIP 50048 |
37.36 |
| 2026-10-07 00:00 |
10:10:26.83 |
+22:54:38.9 |
HIP 50048 |
36.56 |
| 2026-10-07 12:00 |
10:10:30.25 |
+22:54:31.0 |
HIP 50048 |
35.76 |
| 2026-10-08 00:00 |
10:10:33.64 |
+22:54:23.4 |
HIP 50048 |
34.98 |
| 2026-10-08 12:00 |
10:10:37.00 |
+22:54:16.0 |
HIP 50048 |
34.20 |
| 2026-10-09 00:00 |
10:10:40.33 |
+22:54:08.9 |
HIP 50048 |
33.42 |
| 2026-10-09 12:00 |
10:10:43.63 |
+22:54:02.0 |
HIP 50048 |
32.66 |
| 2026-10-10 00:00 |
10:10:46.89 |
+22:53:55.4 |
HIP 50048 |
31.90 |
| 2026-10-10 12:00 |
10:10:50.13 |
+22:53:49.1 |
HIP 50048 |
31.15 |
| 2026-10-11 00:00 |
10:10:53.33 |
+22:53:43.1 |
HIP 50048 |
30.41 |