メタデータ
| 項目 |
値 |
| Designation |
C/1987 P1 (Bradfield) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1987-11-07T06:34:43.440960Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:33Z |
| Obs used |
611 |
| NEO |
- |
| M1 |
6.000 |
| 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) |
1987-11-29.0000000 |
| e |
0.99473713 |
| q (au) |
0.868956 |
| a (au) |
165.110625 |
| i (deg) |
34.088067 |
| Ω (om, deg) |
268.092924 |
| ω (w, deg) |
73.899611 |
| M (ma, deg) |
0.010093 |
等級
散乱 + 全体線形
$$
M_a = (5.750 + 2.678\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
5.750 |
| n |
2.678 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
1.000 |
| 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 |
| 1987-08-12 |
1987-11-06 |
+1.8670 |
+0.018 |
| 1987-11-07 |
1987-12-09 |
+1.4060 |
+0.081 |
| 1987-12-09 |
1988-03-08 |
-0.4160 |
+0.009 |
| 1988-03-08 |
1988-04-11 |
+8.3598 |
-2.815 |
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 |
09:05:37.88 |
-14:22:50.8 |
HIP 44639 |
24.98 |
| 2026-05-12 12:00 |
09:05:38.14 |
-14:22:37.0 |
HIP 44639 |
25.20 |
| 2026-05-13 00:00 |
09:05:38.41 |
-14:22:23.4 |
HIP 44639 |
25.43 |
| 2026-05-13 12:00 |
09:05:38.70 |
-14:22:09.8 |
HIP 44639 |
25.65 |
| 2026-05-14 00:00 |
09:05:39.01 |
-14:21:56.3 |
HIP 44639 |
25.86 |
| 2026-05-14 12:00 |
09:05:39.33 |
-14:21:42.9 |
HIP 44639 |
26.08 |
| 2026-05-15 00:00 |
09:05:39.67 |
-14:21:29.6 |
HIP 44639 |
26.30 |
| 2026-05-15 12:00 |
09:05:40.02 |
-14:21:16.4 |
HIP 44639 |
26.51 |
| 2026-05-16 00:00 |
09:05:40.40 |
-14:21:03.2 |
HIP 44639 |
26.73 |
| 2026-05-16 12:00 |
09:05:40.78 |
-14:20:50.2 |
HIP 44639 |
26.94 |
| 2026-05-17 00:00 |
09:05:41.18 |
-14:20:37.2 |
HIP 44639 |
27.15 |
| 2026-05-17 12:00 |
09:05:41.60 |
-14:20:24.3 |
HIP 44639 |
27.36 |
| 2026-05-18 00:00 |
09:05:42.04 |
-14:20:11.6 |
HIP 44639 |
27.57 |
| 2026-05-18 12:00 |
09:05:42.49 |
-14:19:58.9 |
HIP 44639 |
27.78 |
| 2026-05-19 00:00 |
09:05:42.95 |
-14:19:46.3 |
HIP 44639 |
27.98 |
| 2026-05-19 12:00 |
09:05:43.43 |
-14:19:33.8 |
HIP 44639 |
28.19 |
| 2026-05-20 00:00 |
09:05:43.93 |
-14:19:21.3 |
HIP 44639 |
28.39 |
| 2026-05-20 12:00 |
09:05:44.45 |
-14:19:09.0 |
HIP 44639 |
28.59 |
| 2026-05-21 00:00 |
09:05:44.97 |
-14:18:56.8 |
HIP 44639 |
28.80 |
| 2026-05-21 12:00 |
09:05:45.52 |
-14:18:44.7 |
HIP 44639 |
29.00 |
| 2026-05-22 00:00 |
09:05:46.08 |
-14:18:32.7 |
HIP 44639 |
29.20 |
| 2026-05-22 12:00 |
09:05:46.65 |
-14:18:20.8 |
HIP 44639 |
29.39 |
| 2026-05-23 00:00 |
09:05:47.24 |
-14:18:08.9 |
HIP 44639 |
29.59 |
| 2026-05-23 12:00 |
09:05:47.85 |
-14:17:57.2 |
HIP 44639 |
29.79 |
| 2026-05-24 00:00 |
09:05:48.47 |
-14:17:45.6 |
HIP 44639 |
29.98 |
| 2026-05-24 12:00 |
09:05:49.11 |
-14:17:34.1 |
HIP 44639 |
30.18 |
| 2026-05-25 00:00 |
09:05:49.76 |
-14:17:22.7 |
HIP 44639 |
30.37 |
| 2026-05-25 12:00 |
09:05:50.42 |
-14:17:11.3 |
HIP 44639 |
30.57 |
| 2026-05-26 00:00 |
09:05:51.11 |
-14:17:00.1 |
HIP 44639 |
30.76 |
| 2026-05-26 12:00 |
09:05:51.80 |
-14:16:49.0 |
HIP 44639 |
30.95 |
| 2026-05-27 00:00 |
09:05:52.51 |
-14:16:38.0 |
HIP 44639 |
31.14 |
| 2026-05-27 12:00 |
09:05:53.24 |
-14:16:27.1 |
HIP 44639 |
31.33 |
| 2026-05-28 00:00 |
09:05:53.98 |
-14:16:16.4 |
HIP 44639 |
31.52 |
| 2026-05-28 12:00 |
09:05:54.74 |
-14:16:05.7 |
HIP 44639 |
31.71 |
| 2026-05-29 00:00 |
09:05:55.51 |
-14:15:55.1 |
HIP 44639 |
31.90 |
| 2026-05-29 12:00 |
09:05:56.29 |
-14:15:44.6 |
HIP 44639 |
32.09 |
| 2026-05-30 00:00 |
09:05:57.09 |
-14:15:34.3 |
HIP 44639 |
32.27 |
| 2026-05-30 12:00 |
09:05:57.90 |
-14:15:24.0 |
HIP 44639 |
32.46 |
| 2026-05-31 00:00 |
09:05:58.73 |
-14:15:13.9 |
HIP 44639 |
32.64 |
| 2026-05-31 12:00 |
09:05:59.57 |
-14:15:03.9 |
HIP 44639 |
32.83 |
| 2026-06-01 00:00 |
09:06:00.43 |
-14:14:54.0 |
HIP 44639 |
33.02 |
| 2026-06-01 12:00 |
09:06:01.30 |
-14:14:44.2 |
HIP 44639 |
33.20 |
| 2026-06-02 00:00 |
09:06:02.18 |
-14:14:34.5 |
HIP 44639 |
33.38 |