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) |
| 2026-09-25 00:00 |
09:12:16.20 |
-14:32:31.9 |
HIP 45263 |
23.37 |
| 2026-09-25 12:00 |
09:12:17.53 |
-14:32:48.0 |
HIP 45263 |
23.29 |
| 2026-09-26 00:00 |
09:12:18.84 |
-14:33:04.3 |
HIP 45263 |
23.23 |
| 2026-09-26 12:00 |
09:12:20.14 |
-14:33:20.6 |
HIP 45263 |
23.17 |
| 2026-09-27 00:00 |
09:12:21.43 |
-14:33:36.9 |
HIP 45263 |
23.13 |
| 2026-09-27 12:00 |
09:12:22.70 |
-14:33:53.2 |
HIP 45263 |
23.09 |
| 2026-09-28 00:00 |
09:12:23.97 |
-14:34:09.6 |
HIP 45263 |
23.07 |
| 2026-09-28 12:00 |
09:12:25.22 |
-14:34:26.1 |
HIP 45263 |
23.05 |
| 2026-09-29 00:00 |
09:12:26.46 |
-14:34:42.6 |
HIP 45263 |
23.05 |
| 2026-09-29 12:00 |
09:12:27.69 |
-14:34:59.1 |
HIP 45263 |
23.05 |
| 2026-09-30 00:00 |
09:12:28.90 |
-14:35:15.6 |
HIP 45263 |
23.06 |
| 2026-09-30 12:00 |
09:12:30.10 |
-14:35:32.2 |
HIP 45263 |
23.08 |
| 2026-10-01 00:00 |
09:12:31.29 |
-14:35:48.8 |
HIP 45305 |
22.97 |
| 2026-10-01 12:00 |
09:12:32.47 |
-14:36:05.4 |
HIP 45305 |
22.62 |
| 2026-10-02 00:00 |
09:12:33.64 |
-14:36:22.1 |
HIP 45305 |
22.28 |
| 2026-10-02 12:00 |
09:12:34.79 |
-14:36:38.8 |
HIP 45305 |
21.94 |
| 2026-10-03 00:00 |
09:12:35.93 |
-14:36:55.5 |
HIP 45305 |
21.61 |
| 2026-10-03 12:00 |
09:12:37.06 |
-14:37:12.3 |
HIP 45305 |
21.29 |
| 2026-10-04 00:00 |
09:12:38.17 |
-14:37:29.0 |
HIP 45305 |
20.97 |
| 2026-10-04 12:00 |
09:12:39.27 |
-14:37:45.8 |
HIP 45305 |
20.65 |
| 2026-10-05 00:00 |
09:12:40.36 |
-14:38:02.7 |
HIP 45305 |
20.34 |
| 2026-10-05 12:00 |
09:12:41.43 |
-14:38:19.5 |
HIP 45305 |
20.03 |
| 2026-10-06 00:00 |
09:12:42.49 |
-14:38:36.4 |
HIP 45305 |
19.74 |
| 2026-10-06 12:00 |
09:12:43.54 |
-14:38:53.3 |
HIP 45305 |
19.44 |
| 2026-10-07 00:00 |
09:12:44.57 |
-14:39:10.2 |
HIP 45305 |
19.16 |
| 2026-10-07 12:00 |
09:12:45.59 |
-14:39:27.1 |
HIP 45305 |
18.88 |
| 2026-10-08 00:00 |
09:12:46.60 |
-14:39:44.1 |
HIP 45305 |
18.60 |
| 2026-10-08 12:00 |
09:12:47.59 |
-14:40:01.0 |
HIP 45305 |
18.34 |
| 2026-10-09 00:00 |
09:12:48.57 |
-14:40:18.0 |
HIP 45305 |
18.08 |
| 2026-10-09 12:00 |
09:12:49.53 |
-14:40:35.0 |
HIP 45305 |
17.82 |
| 2026-10-10 00:00 |
09:12:50.48 |
-14:40:52.0 |
HIP 45305 |
17.58 |
| 2026-10-10 12:00 |
09:12:51.42 |
-14:41:09.0 |
HIP 45305 |
17.34 |
| 2026-10-11 00:00 |
09:12:52.34 |
-14:41:26.0 |
HIP 45305 |
17.11 |
| 2026-10-11 12:00 |
09:12:53.25 |
-14:41:43.0 |
HIP 45305 |
16.89 |
| 2026-10-12 00:00 |
09:12:54.14 |
-14:42:00.0 |
HIP 45305 |
16.68 |
| 2026-10-12 12:00 |
09:12:55.02 |
-14:42:17.0 |
HIP 45305 |
16.47 |
| 2026-10-13 00:00 |
09:12:55.88 |
-14:42:34.1 |
HIP 45305 |
16.28 |
| 2026-10-13 12:00 |
09:12:56.73 |
-14:42:51.1 |
HIP 45305 |
16.09 |
| 2026-10-14 00:00 |
09:12:57.56 |
-14:43:08.1 |
HIP 45305 |
15.91 |
| 2026-10-14 12:00 |
09:12:58.38 |
-14:43:25.2 |
HIP 45305 |
15.74 |
| 2026-10-15 00:00 |
09:12:59.19 |
-14:43:42.2 |
HIP 45305 |
15.58 |
| 2026-10-15 12:00 |
09:12:59.98 |
-14:43:59.2 |
HIP 45305 |
15.43 |
| 2026-10-16 00:00 |
09:13:00.75 |
-14:44:16.3 |
HIP 45305 |
15.29 |