メタデータ
| 項目 |
値 |
| Designation |
C/1984 A1 (Bradfield 1) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1983-12-27T19:07:03.864000Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:31Z |
| Obs used |
33 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
1984-02-25.0000000 |
| e |
0.95231517 |
| q (au) |
1.357490 |
| a (au) |
28.467973 |
| i (deg) |
51.800566 |
| Ω (om, deg) |
356.858343 |
| ω (w, deg) |
219.164863 |
| M (ma, deg) |
0.384163 |
等級
散乱 + 全体線形
$$
M_a = (7.897 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
7.897 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| 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
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
00:25:32.78 |
+30:48:14.2 |
HIP 2170 |
24.35 |
| 2026-09-20 12:00 |
00:25:30.16 |
+30:48:05.2 |
HIP 2170 |
24.93 |
| 2026-09-21 00:00 |
00:25:27.53 |
+30:47:56.0 |
HIP 2170 |
25.51 |
| 2026-09-21 12:00 |
00:25:24.89 |
+30:47:46.7 |
HIP 2170 |
26.10 |
| 2026-09-22 00:00 |
00:25:22.25 |
+30:47:37.2 |
HIP 2170 |
26.69 |
| 2026-09-22 12:00 |
00:25:19.61 |
+30:47:27.5 |
HIP 2170 |
27.28 |
| 2026-09-23 00:00 |
00:25:16.97 |
+30:47:17.7 |
HIP 2170 |
27.87 |
| 2026-09-23 12:00 |
00:25:14.32 |
+30:47:07.7 |
HIP 2170 |
28.46 |
| 2026-09-24 00:00 |
00:25:11.67 |
+30:46:57.5 |
HIP 1903 |
28.42 |
| 2026-09-24 12:00 |
00:25:09.02 |
+30:46:47.2 |
HIP 1903 |
28.28 |
| 2026-09-25 00:00 |
00:25:06.36 |
+30:46:36.6 |
HIP 1903 |
28.16 |
| 2026-09-25 12:00 |
00:25:03.71 |
+30:46:26.0 |
HIP 1903 |
28.04 |
| 2026-09-26 00:00 |
00:25:01.05 |
+30:46:15.1 |
HIP 1903 |
27.95 |
| 2026-09-26 12:00 |
00:24:58.39 |
+30:46:04.1 |
HIP 1903 |
27.87 |
| 2026-09-27 00:00 |
00:24:55.73 |
+30:45:53.0 |
HIP 1903 |
27.80 |
| 2026-09-27 12:00 |
00:24:53.06 |
+30:45:41.7 |
HIP 1903 |
27.75 |
| 2026-09-28 00:00 |
00:24:50.40 |
+30:45:30.2 |
HIP 1903 |
27.71 |
| 2026-09-28 12:00 |
00:24:47.74 |
+30:45:18.5 |
HIP 1903 |
27.69 |
| 2026-09-29 00:00 |
00:24:45.07 |
+30:45:06.7 |
HIP 1903 |
27.69 |
| 2026-09-29 12:00 |
00:24:42.40 |
+30:44:54.7 |
HIP 1903 |
27.70 |
| 2026-09-30 00:00 |
00:24:39.74 |
+30:44:42.6 |
HIP 1903 |
27.72 |
| 2026-09-30 12:00 |
00:24:37.07 |
+30:44:30.3 |
HIP 1903 |
27.77 |
| 2026-10-01 00:00 |
00:24:34.40 |
+30:44:17.9 |
HIP 1903 |
27.82 |
| 2026-10-01 12:00 |
00:24:31.74 |
+30:44:05.3 |
HIP 1903 |
27.90 |
| 2026-10-02 00:00 |
00:24:29.07 |
+30:43:52.6 |
HIP 1903 |
27.99 |
| 2026-10-02 12:00 |
00:24:26.41 |
+30:43:39.7 |
HIP 1903 |
28.09 |
| 2026-10-03 00:00 |
00:24:23.74 |
+30:43:26.6 |
HIP 1903 |
28.21 |
| 2026-10-03 12:00 |
00:24:21.08 |
+30:43:13.4 |
HIP 1903 |
28.34 |
| 2026-10-04 00:00 |
00:24:18.42 |
+30:43:00.0 |
HIP 1903 |
28.49 |
| 2026-10-04 12:00 |
00:24:15.76 |
+30:42:46.5 |
HIP 1903 |
28.66 |
| 2026-10-05 00:00 |
00:24:13.10 |
+30:42:32.9 |
HIP 1903 |
28.84 |
| 2026-10-05 12:00 |
00:24:10.45 |
+30:42:19.1 |
HIP 1903 |
29.03 |
| 2026-10-06 00:00 |
00:24:07.79 |
+30:42:05.1 |
HIP 1903 |
29.24 |
| 2026-10-06 12:00 |
00:24:05.14 |
+30:41:51.0 |
HIP 1903 |
29.46 |
| 2026-10-07 00:00 |
00:24:02.49 |
+30:41:36.8 |
HIP 1903 |
29.70 |
| 2026-10-07 12:00 |
00:23:59.85 |
+30:41:22.4 |
HIP 1903 |
29.95 |
| 2026-10-08 00:00 |
00:23:57.20 |
+30:41:07.9 |
HIP 1903 |
30.21 |
| 2026-10-08 12:00 |
00:23:54.56 |
+30:40:53.2 |
HIP 1903 |
30.48 |
| 2026-10-09 00:00 |
00:23:51.93 |
+30:40:38.4 |
HIP 1903 |
30.77 |
| 2026-10-09 12:00 |
00:23:49.30 |
+30:40:23.5 |
HIP 1903 |
31.07 |
| 2026-10-10 00:00 |
00:23:46.67 |
+30:40:08.4 |
HIP 1903 |
31.38 |
| 2026-10-10 12:00 |
00:23:44.04 |
+30:39:53.1 |
HIP 1903 |
31.70 |
| 2026-10-11 00:00 |
00:23:41.42 |
+30:39:37.8 |
HIP 1903 |
32.03 |