C/1987 P1 (Bradfield)
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
$$
M_a = (5.752 + 2.677\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
5.752 |
| n |
2.677 |
| 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 |
+1.8785 |
+0.025 |
| 1987-11-07 |
1987-12-09 |
+1.7069 |
+0.090 |
| 1987-12-09 |
1988-02-23 |
-0.7228 |
+0.040 |
| 1988-02-23 |
1988-03-18 |
+9.8943 |
-3.171 |
| 1988-03-18 |
1988-04-11 |
+1.3619 |
-0.135 |
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) |
| 2026-02-03 00:00 |
09:09:21.90 |
-15:09:02.8 |
HIP 44860 |
13.60 |
| 2026-02-03 12:00 |
09:09:19.93 |
-15:08:55.9 |
HIP 44860 |
13.12 |
| 2026-02-04 00:00 |
09:09:17.95 |
-15:08:48.9 |
HIP 44860 |
12.64 |
| 2026-02-04 12:00 |
09:09:15.98 |
-15:08:41.8 |
HIP 44860 |
12.17 |
| 2026-02-05 00:00 |
09:09:14.00 |
-15:08:34.5 |
HIP 44860 |
11.69 |
| 2026-02-05 12:00 |
09:09:12.03 |
-15:08:27.1 |
HIP 44860 |
11.22 |
| 2026-02-06 00:00 |
09:09:10.06 |
-15:08:19.5 |
HIP 44860 |
10.74 |
| 2026-02-06 12:00 |
09:09:08.08 |
-15:08:11.8 |
HIP 44860 |
10.27 |
| 2026-02-07 00:00 |
09:09:06.11 |
-15:08:04.0 |
HIP 44860 |
9.80 |
| 2026-02-07 12:00 |
09:09:04.14 |
-15:07:56.0 |
HIP 44860 |
9.34 |
| 2026-02-08 00:00 |
09:09:02.17 |
-15:07:47.9 |
HIP 44860 |
8.88 |
| 2026-02-08 12:00 |
09:09:00.20 |
-15:07:39.7 |
HIP 44860 |
8.42 |
| 2026-02-09 00:00 |
09:08:58.23 |
-15:07:31.3 |
HIP 44860 |
7.97 |
| 2026-02-09 12:00 |
09:08:56.26 |
-15:07:22.8 |
HIP 44860 |
7.52 |
| 2026-02-10 00:00 |
09:08:54.30 |
-15:07:14.1 |
HIP 44860 |
7.08 |
| 2026-02-10 12:00 |
09:08:52.33 |
-15:07:05.3 |
HIP 44860 |
6.65 |
| 2026-02-11 00:00 |
09:08:50.37 |
-15:06:56.4 |
HIP 44860 |
6.23 |
| 2026-02-11 12:00 |
09:08:48.41 |
-15:06:47.4 |
HIP 44860 |
5.82 |
| 2026-02-12 00:00 |
09:08:46.46 |
-15:06:38.2 |
HIP 44860 |
5.43 |
| 2026-02-12 12:00 |
09:08:44.50 |
-15:06:28.9 |
HIP 44860 |
5.06 |
| 2026-02-13 00:00 |
09:08:42.55 |
-15:06:19.5 |
HIP 44860 |
4.72 |
| 2026-02-13 12:00 |
09:08:40.60 |
-15:06:09.9 |
HIP 44860 |
4.40 |
| 2026-02-14 00:00 |
09:08:38.66 |
-15:06:00.3 |
HIP 44860 |
4.13 |
| 2026-02-14 12:00 |
09:08:36.72 |
-15:05:50.5 |
HIP 44860 |
3.90 |
| 2026-02-15 00:00 |
09:08:34.78 |
-15:05:40.5 |
HIP 44860 |
3.72 |
| 2026-02-15 12:00 |
09:08:32.84 |
-15:05:30.5 |
HIP 44860 |
3.61 |
| 2026-02-16 00:00 |
09:08:30.91 |
-15:05:20.3 |
HIP 44860 |
3.56 |
| 2026-02-16 12:00 |
09:08:28.98 |
-15:05:10.0 |
HIP 44860 |
3.59 |
| 2026-02-17 00:00 |
09:08:27.06 |
-15:04:59.6 |
HIP 44860 |
3.68 |
| 2026-02-17 12:00 |
09:08:25.14 |
-15:04:49.0 |
HIP 44860 |
3.84 |
| 2026-02-18 00:00 |
09:08:23.23 |
-15:04:38.3 |
HIP 44860 |
4.06 |
| 2026-02-18 12:00 |
09:08:21.32 |
-15:04:27.6 |
HIP 44860 |
4.32 |
| 2026-02-19 00:00 |
09:08:19.41 |
-15:04:16.7 |
HIP 44860 |
4.62 |
| 2026-02-19 12:00 |
09:08:17.51 |
-15:04:05.6 |
HIP 44860 |
4.96 |
| 2026-02-20 00:00 |
09:08:15.61 |
-15:03:54.5 |
HIP 44860 |
5.32 |
| 2026-02-20 12:00 |
09:08:13.72 |
-15:03:43.3 |
HIP 44860 |
5.70 |
| 2026-02-21 00:00 |
09:08:11.84 |
-15:03:31.9 |
HIP 44860 |
6.10 |
| 2026-02-21 12:00 |
09:08:09.96 |
-15:03:20.4 |
HIP 44860 |
6.52 |
| 2026-02-22 00:00 |
09:08:08.08 |
-15:03:08.8 |
HIP 44860 |
6.94 |
| 2026-02-22 12:00 |
09:08:06.22 |
-15:02:57.1 |
HIP 44860 |
7.37 |
| 2026-02-23 00:00 |
09:08:04.35 |
-15:02:45.3 |
HIP 44860 |
7.81 |
| 2026-02-23 12:00 |
09:08:02.50 |
-15:02:33.4 |
HIP 44860 |
8.26 |
| 2026-02-24 00:00 |
09:08:00.65 |
-15:02:21.4 |
HIP 44860 |
8.71 |