メタデータ
| 項目 |
値 |
| Designation |
C/2020 P1 (NEOWISE) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2020-10-20T04:17:44.208960Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:34:09Z |
| Obs used |
136 |
| NEO |
- |
| M1 |
15.300 |
| K1 |
5.250 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2020-08-02T15:00:32.832000Z |
| Discovery magnitude (MPC) |
19.00 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) |
2020-09-09.0000000 |
| e |
1.00029689 |
| q (au) |
0.342183 |
| a (au) |
-1152.562177 |
| i (deg) |
45.053817 |
| Ω (om, deg) |
53.539366 |
| ω (w, deg) |
8.894962 |
| M (ma, deg) |
-0.001037 |
等級
散乱 + 全体線形
$$
M_a = (14.493 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
14.493 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.502 |
| 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 |
| 2020-08-02 |
2020-09-20 |
+1.4276 |
-0.325 |
| 2020-09-20 |
2020-10-05 |
-8.5024 |
-2.547 |
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) |
| 2026-05-12 00:00 |
15:09:02.49 |
-11:57:44.8 |
HIP 74127 |
10.42 |
| 2026-05-12 12:00 |
15:08:55.61 |
-11:57:20.8 |
HIP 74127 |
9.92 |
| 2026-05-13 00:00 |
15:08:48.74 |
-11:56:56.9 |
HIP 74127 |
9.72 |
| 2026-05-13 12:00 |
15:08:41.87 |
-11:56:33.1 |
HIP 74127 |
9.82 |
| 2026-05-14 00:00 |
15:08:35.01 |
-11:56:09.4 |
HIP 74059 |
9.82 |
| 2026-05-14 12:00 |
15:08:28.15 |
-11:55:45.7 |
HIP 74059 |
9.03 |
| 2026-05-15 00:00 |
15:08:21.30 |
-11:55:22.2 |
HIP 74059 |
8.51 |
| 2026-05-15 12:00 |
15:08:14.46 |
-11:54:58.8 |
HIP 74059 |
8.33 |
| 2026-05-16 00:00 |
15:08:07.62 |
-11:54:35.5 |
HIP 74059 |
8.49 |
| 2026-05-16 12:00 |
15:08:00.80 |
-11:54:12.4 |
HIP 74059 |
8.98 |
| 2026-05-17 00:00 |
15:07:53.98 |
-11:53:49.3 |
HIP 74059 |
9.75 |
| 2026-05-17 12:00 |
15:07:47.18 |
-11:53:26.4 |
HIP 74059 |
10.73 |
| 2026-05-18 00:00 |
15:07:40.39 |
-11:53:03.6 |
HIP 74059 |
11.88 |
| 2026-05-18 12:00 |
15:07:33.60 |
-11:52:40.9 |
HIP 74059 |
13.14 |
| 2026-05-19 00:00 |
15:07:26.83 |
-11:52:18.3 |
HIP 74059 |
14.49 |
| 2026-05-19 12:00 |
15:07:20.08 |
-11:51:55.9 |
HIP 74048 |
15.71 |
| 2026-05-20 00:00 |
15:07:13.33 |
-11:51:33.5 |
HIP 74048 |
16.44 |
| 2026-05-20 12:00 |
15:07:06.60 |
-11:51:11.4 |
HIP 74048 |
17.29 |
| 2026-05-21 00:00 |
15:06:59.89 |
-11:50:49.3 |
HIP 74048 |
18.27 |
| 2026-05-21 12:00 |
15:06:53.18 |
-11:50:27.4 |
HIP 74048 |
19.34 |
| 2026-05-22 00:00 |
15:06:46.50 |
-11:50:05.7 |
HIP 74048 |
20.48 |
| 2026-05-22 12:00 |
15:06:39.83 |
-11:49:44.0 |
HIP 74048 |
21.70 |
| 2026-05-23 00:00 |
15:06:33.18 |
-11:49:22.6 |
HIP 74048 |
22.97 |
| 2026-05-23 12:00 |
15:06:26.55 |
-11:49:01.2 |
HIP 74048 |
24.29 |
| 2026-05-24 00:00 |
15:06:19.93 |
-11:48:40.0 |
HIP 74048 |
25.64 |
| 2026-05-24 12:00 |
15:06:13.33 |
-11:48:19.0 |
HIP 73760 |
24.34 |
| 2026-05-25 00:00 |
15:06:06.75 |
-11:47:58.1 |
HIP 73760 |
22.71 |
| 2026-05-25 12:00 |
15:06:00.19 |
-11:47:37.4 |
HIP 73760 |
21.09 |
| 2026-05-26 00:00 |
15:05:53.65 |
-11:47:16.8 |
HIP 73760 |
19.48 |
| 2026-05-26 12:00 |
15:05:47.13 |
-11:46:56.4 |
HIP 73760 |
17.87 |
| 2026-05-27 00:00 |
15:05:40.64 |
-11:46:36.1 |
HIP 73760 |
16.28 |
| 2026-05-27 12:00 |
15:05:34.16 |
-11:46:16.0 |
HIP 73760 |
14.70 |
| 2026-05-28 00:00 |
15:05:27.71 |
-11:45:56.1 |
HIP 73760 |
13.14 |
| 2026-05-28 12:00 |
15:05:21.27 |
-11:45:36.3 |
HIP 73760 |
11.60 |
| 2026-05-29 00:00 |
15:05:14.86 |
-11:45:16.7 |
HIP 73760 |
10.08 |
| 2026-05-29 12:00 |
15:05:08.48 |
-11:44:57.2 |
HIP 73760 |
8.61 |
| 2026-05-30 00:00 |
15:05:02.12 |
-11:44:37.9 |
HIP 73760 |
7.19 |
| 2026-05-30 12:00 |
15:04:55.78 |
-11:44:18.8 |
HIP 73760 |
5.86 |
| 2026-05-31 00:00 |
15:04:49.47 |
-11:43:59.9 |
HIP 73760 |
4.71 |
| 2026-05-31 12:00 |
15:04:43.18 |
-11:43:41.1 |
HIP 73760 |
3.87 |
| 2026-06-01 00:00 |
15:04:36.92 |
-11:43:22.5 |
HIP 73760 |
3.56 |
| 2026-06-01 12:00 |
15:04:30.69 |
-11:43:04.1 |
HIP 73760 |
3.91 |
| 2026-06-02 00:00 |
15:04:24.48 |
-11:42:45.8 |
HIP 73760 |
4.77 |