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) |
| 2026-03-26 00:00 |
15:18:46.31 |
-12:36:49.9 |
HIP 74897 |
19.38 |
| 2026-03-26 12:00 |
15:18:41.56 |
-12:36:27.6 |
HIP 74897 |
19.47 |
| 2026-03-27 00:00 |
15:18:36.77 |
-12:36:05.1 |
HIP 74897 |
19.62 |
| 2026-03-27 12:00 |
15:18:31.93 |
-12:35:42.4 |
HIP 74897 |
19.86 |
| 2026-03-28 00:00 |
15:18:27.04 |
-12:35:19.7 |
HIP 74897 |
20.17 |
| 2026-03-28 12:00 |
15:18:22.11 |
-12:34:56.8 |
HIP 74897 |
20.55 |
| 2026-03-29 00:00 |
15:18:17.13 |
-12:34:33.9 |
HIP 74897 |
21.01 |
| 2026-03-29 12:00 |
15:18:12.11 |
-12:34:10.8 |
HIP 74897 |
21.53 |
| 2026-03-30 00:00 |
15:18:07.05 |
-12:33:47.6 |
HIP 74897 |
22.12 |
| 2026-03-30 12:00 |
15:18:01.94 |
-12:33:24.3 |
HIP 74897 |
22.77 |
| 2026-03-31 00:00 |
15:17:56.79 |
-12:33:00.9 |
HIP 74897 |
23.48 |
| 2026-03-31 12:00 |
15:17:51.59 |
-12:32:37.3 |
HIP 74897 |
24.25 |
| 2026-04-01 00:00 |
15:17:46.36 |
-12:32:13.7 |
HIP 74897 |
25.07 |
| 2026-04-01 12:00 |
15:17:41.08 |
-12:31:50.0 |
HIP 74897 |
25.94 |
| 2026-04-02 00:00 |
15:17:35.76 |
-12:31:26.2 |
HIP 74897 |
26.85 |
| 2026-04-02 12:00 |
15:17:30.40 |
-12:31:02.3 |
HIP 74897 |
27.81 |
| 2026-04-03 00:00 |
15:17:25.00 |
-12:30:38.2 |
HIP 74897 |
28.80 |
| 2026-04-03 12:00 |
15:17:19.56 |
-12:30:14.1 |
HIP 74897 |
29.84 |
| 2026-04-04 00:00 |
15:17:14.09 |
-12:29:49.9 |
HIP 74897 |
30.90 |
| 2026-04-04 12:00 |
15:17:08.57 |
-12:29:25.6 |
HIP 74897 |
32.00 |
| 2026-04-05 00:00 |
15:17:03.01 |
-12:29:01.3 |
HIP 74897 |
33.13 |
| 2026-04-05 12:00 |
15:16:57.42 |
-12:28:36.8 |
HIP 74765 |
33.81 |
| 2026-04-06 00:00 |
15:16:51.79 |
-12:28:12.3 |
HIP 74765 |
34.16 |
| 2026-04-06 12:00 |
15:16:46.12 |
-12:27:47.6 |
HIP 74765 |
34.56 |
| 2026-04-07 00:00 |
15:16:40.41 |
-12:27:22.9 |
HIP 74765 |
35.03 |
| 2026-04-07 12:00 |
15:16:34.67 |
-12:26:58.2 |
HIP 74765 |
35.54 |
| 2026-04-08 00:00 |
15:16:28.89 |
-12:26:33.3 |
HIP 74765 |
36.12 |
| 2026-04-08 12:00 |
15:16:23.08 |
-12:26:08.4 |
HIP 74765 |
36.74 |
| 2026-04-09 00:00 |
15:16:17.23 |
-12:25:43.4 |
HIP 74533 |
36.76 |
| 2026-04-09 12:00 |
15:16:11.34 |
-12:25:18.3 |
HIP 74533 |
35.30 |
| 2026-04-10 00:00 |
15:16:05.43 |
-12:24:53.2 |
HIP 74533 |
33.83 |
| 2026-04-10 12:00 |
15:15:59.48 |
-12:24:28.0 |
HIP 74533 |
32.36 |
| 2026-04-11 00:00 |
15:15:53.50 |
-12:24:02.8 |
HIP 74533 |
30.88 |
| 2026-04-11 12:00 |
15:15:47.48 |
-12:23:37.5 |
HIP 74533 |
29.40 |
| 2026-04-12 00:00 |
15:15:41.43 |
-12:23:12.1 |
HIP 74533 |
27.91 |
| 2026-04-12 12:00 |
15:15:35.36 |
-12:22:46.7 |
HIP 74533 |
26.43 |
| 2026-04-13 00:00 |
15:15:29.25 |
-12:22:21.2 |
HIP 74533 |
24.94 |
| 2026-04-13 12:00 |
15:15:23.11 |
-12:21:55.7 |
HIP 74533 |
23.45 |
| 2026-04-14 00:00 |
15:15:16.94 |
-12:21:30.2 |
HIP 74533 |
21.97 |
| 2026-04-14 12:00 |
15:15:10.74 |
-12:21:04.6 |
HIP 74533 |
20.49 |
| 2026-04-15 00:00 |
15:15:04.52 |
-12:20:38.9 |
HIP 74533 |
19.02 |
| 2026-04-15 12:00 |
15:14:58.26 |
-12:20:13.3 |
HIP 74533 |
17.56 |
| 2026-04-16 00:00 |
15:14:51.98 |
-12:19:47.5 |
HIP 74533 |
16.12 |