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) |
| 2026-07-29 00:00 |
09:59:48.92 |
+23:45:13.2 |
HIP 48973 |
28.46 |
| 2026-07-29 12:00 |
09:59:53.53 |
+23:44:43.0 |
HIP 48973 |
28.21 |
| 2026-07-30 00:00 |
09:59:58.16 |
+23:44:12.8 |
HIP 48973 |
28.00 |
| 2026-07-30 12:00 |
10:00:02.80 |
+23:43:42.6 |
HIP 48973 |
27.84 |
| 2026-07-31 00:00 |
10:00:07.46 |
+23:43:12.5 |
HIP 48973 |
27.74 |
| 2026-07-31 12:00 |
10:00:12.13 |
+23:42:42.4 |
HIP 48973 |
27.69 |
| 2026-08-01 00:00 |
10:00:16.81 |
+23:42:12.4 |
HIP 49153 |
27.60 |
| 2026-08-01 12:00 |
10:00:21.50 |
+23:41:42.5 |
HIP 49153 |
27.07 |
| 2026-08-02 00:00 |
10:00:26.21 |
+23:41:12.6 |
HIP 49153 |
26.58 |
| 2026-08-02 12:00 |
10:00:30.93 |
+23:40:42.8 |
HIP 49153 |
26.12 |
| 2026-08-03 00:00 |
10:00:35.66 |
+23:40:13.0 |
HIP 49153 |
25.71 |
| 2026-08-03 12:00 |
10:00:40.41 |
+23:39:43.3 |
HIP 49153 |
25.35 |
| 2026-08-04 00:00 |
10:00:45.16 |
+23:39:13.6 |
HIP 49153 |
25.04 |
| 2026-08-04 12:00 |
10:00:49.92 |
+23:38:44.0 |
HIP 49153 |
24.78 |
| 2026-08-05 00:00 |
10:00:54.70 |
+23:38:14.5 |
HIP 49153 |
24.57 |
| 2026-08-05 12:00 |
10:00:59.48 |
+23:37:45.0 |
HIP 49153 |
24.42 |
| 2026-08-06 00:00 |
10:01:04.28 |
+23:37:15.6 |
HIP 49153 |
24.32 |
| 2026-08-06 12:00 |
10:01:09.09 |
+23:36:46.3 |
HIP 49153 |
24.28 |
| 2026-08-07 00:00 |
10:01:13.90 |
+23:36:17.1 |
HIP 49153 |
24.30 |
| 2026-08-07 12:00 |
10:01:18.72 |
+23:35:47.9 |
HIP 49153 |
24.38 |
| 2026-08-08 00:00 |
10:01:23.56 |
+23:35:18.8 |
HIP 49153 |
24.51 |
| 2026-08-08 12:00 |
10:01:28.40 |
+23:34:49.8 |
HIP 49153 |
24.70 |
| 2026-08-09 00:00 |
10:01:33.25 |
+23:34:20.8 |
HIP 49153 |
24.94 |
| 2026-08-09 12:00 |
10:01:38.10 |
+23:33:52.0 |
HIP 49153 |
25.24 |
| 2026-08-10 00:00 |
10:01:42.97 |
+23:33:23.2 |
HIP 49153 |
25.59 |
| 2026-08-10 12:00 |
10:01:47.84 |
+23:32:54.5 |
HIP 49153 |
25.99 |
| 2026-08-11 00:00 |
10:01:52.71 |
+23:32:25.9 |
HIP 49153 |
26.44 |
| 2026-08-11 12:00 |
10:01:57.60 |
+23:31:57.4 |
HIP 49153 |
26.94 |
| 2026-08-12 00:00 |
10:02:02.49 |
+23:31:28.9 |
HIP 49153 |
27.48 |
| 2026-08-12 12:00 |
10:02:07.38 |
+23:31:00.6 |
HIP 49153 |
28.06 |
| 2026-08-13 00:00 |
10:02:12.28 |
+23:30:32.4 |
HIP 49153 |
28.68 |
| 2026-08-13 12:00 |
10:02:17.19 |
+23:30:04.2 |
HIP 49153 |
29.33 |
| 2026-08-14 00:00 |
10:02:22.10 |
+23:29:36.2 |
HIP 49153 |
30.02 |
| 2026-08-14 12:00 |
10:02:27.01 |
+23:29:08.3 |
HIP 49153 |
30.74 |
| 2026-08-15 00:00 |
10:02:31.93 |
+23:28:40.4 |
HIP 49153 |
31.49 |
| 2026-08-15 12:00 |
10:02:36.85 |
+23:28:12.7 |
HIP 49153 |
32.26 |
| 2026-08-16 00:00 |
10:02:41.77 |
+23:27:45.1 |
HIP 49153 |
33.06 |
| 2026-08-16 12:00 |
10:02:46.70 |
+23:27:17.5 |
HIP 49153 |
33.89 |
| 2026-08-17 00:00 |
10:02:51.63 |
+23:26:50.1 |
HIP 49153 |
34.73 |
| 2026-08-17 12:00 |
10:02:56.56 |
+23:26:22.8 |
HIP 49153 |
35.60 |
| 2026-08-18 00:00 |
10:03:01.49 |
+23:25:55.7 |
HIP 49153 |
36.48 |
| 2026-08-18 12:00 |
10:03:06.42 |
+23:25:28.6 |
HIP 49153 |
37.38 |
| 2026-08-19 00:00 |
10:03:11.36 |
+23:25:01.7 |
HIP 49153 |
38.30 |