メタデータ
| 項目 |
値 |
| Designation |
C/1974 C1 (Bradfield) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1974-03-18T08:33:10.964160Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:22Z |
| Obs used |
173 |
| NEO |
- |
| M1 |
8.600 |
| K1 |
10.000 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
1974-04-20.0000000 |
| e |
0.99973403 |
| q (au) |
0.503190 |
| a (au) |
1891.926449 |
| i (deg) |
61.284581 |
| Ω (om, deg) |
143.733056 |
| ω (w, deg) |
333.133285 |
| M (ma, deg) |
0.000391 |
等級
散乱 + 全体線形
$$
M_a = (7.576 + 2.404\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
7.576 |
| n |
2.404 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
0.989 |
| 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 |
| 1974-02-14 |
1974-03-18 |
-1.9064 |
-0.077 |
| 1974-03-18 |
1974-04-08 |
-3.6784 |
-0.875 |
| 1974-04-08 |
1974-05-07 |
+1.3780 |
+0.127 |
| 1974-05-07 |
1974-06-13 |
-1.2851 |
+0.024 |
| 1974-06-13 |
1974-09-15 |
+11.1440 |
-3.135 |
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) |
| 2026-06-01 00:00 |
20:00:48.10 |
+11:22:57.3 |
HIP 98508 |
21.06 |
| 2026-06-01 12:00 |
20:00:47.11 |
+11:23:03.4 |
HIP 98508 |
21.15 |
| 2026-06-02 00:00 |
20:00:46.10 |
+11:23:09.5 |
HIP 98508 |
21.25 |
| 2026-06-02 12:00 |
20:00:45.09 |
+11:23:15.5 |
HIP 98508 |
21.34 |
| 2026-06-03 00:00 |
20:00:44.06 |
+11:23:21.3 |
HIP 98508 |
21.44 |
| 2026-06-03 12:00 |
20:00:43.03 |
+11:23:27.1 |
HIP 98508 |
21.54 |
| 2026-06-04 00:00 |
20:00:41.99 |
+11:23:32.8 |
HIP 98508 |
21.64 |
| 2026-06-04 12:00 |
20:00:40.94 |
+11:23:38.4 |
HIP 98508 |
21.74 |
| 2026-06-05 00:00 |
20:00:39.88 |
+11:23:43.9 |
HIP 98508 |
21.85 |
| 2026-06-05 12:00 |
20:00:38.81 |
+11:23:49.3 |
HIP 98508 |
21.95 |
| 2026-06-06 00:00 |
20:00:37.73 |
+11:23:54.6 |
HIP 98377 |
21.73 |
| 2026-06-06 12:00 |
20:00:36.64 |
+11:23:59.8 |
HIP 98377 |
21.49 |
| 2026-06-07 00:00 |
20:00:35.55 |
+11:24:04.9 |
HIP 98377 |
21.26 |
| 2026-06-07 12:00 |
20:00:34.44 |
+11:24:10.0 |
HIP 98377 |
21.02 |
| 2026-06-08 00:00 |
20:00:33.33 |
+11:24:14.9 |
HIP 98377 |
20.78 |
| 2026-06-08 12:00 |
20:00:32.20 |
+11:24:19.7 |
HIP 98377 |
20.54 |
| 2026-06-09 00:00 |
20:00:31.07 |
+11:24:24.4 |
HIP 98377 |
20.30 |
| 2026-06-09 12:00 |
20:00:29.93 |
+11:24:29.1 |
HIP 98377 |
20.06 |
| 2026-06-10 00:00 |
20:00:28.79 |
+11:24:33.6 |
HIP 98377 |
19.81 |
| 2026-06-10 12:00 |
20:00:27.63 |
+11:24:38.0 |
HIP 98377 |
19.57 |
| 2026-06-11 00:00 |
20:00:26.47 |
+11:24:42.3 |
HIP 98377 |
19.32 |
| 2026-06-11 12:00 |
20:00:25.29 |
+11:24:46.6 |
HIP 98377 |
19.07 |
| 2026-06-12 00:00 |
20:00:24.11 |
+11:24:50.7 |
HIP 98377 |
18.82 |
| 2026-06-12 12:00 |
20:00:22.93 |
+11:24:54.7 |
HIP 98377 |
18.58 |
| 2026-06-13 00:00 |
20:00:21.73 |
+11:24:58.7 |
HIP 98377 |
18.33 |
| 2026-06-13 12:00 |
20:00:20.53 |
+11:25:02.5 |
HIP 98377 |
18.07 |
| 2026-06-14 00:00 |
20:00:19.31 |
+11:25:06.2 |
HIP 98377 |
17.82 |
| 2026-06-14 12:00 |
20:00:18.10 |
+11:25:09.8 |
HIP 98377 |
17.57 |
| 2026-06-15 00:00 |
20:00:16.87 |
+11:25:13.4 |
HIP 98377 |
17.32 |
| 2026-06-15 12:00 |
20:00:15.63 |
+11:25:16.8 |
HIP 98377 |
17.06 |
| 2026-06-16 00:00 |
20:00:14.39 |
+11:25:20.1 |
HIP 98377 |
16.81 |
| 2026-06-16 12:00 |
20:00:13.14 |
+11:25:23.3 |
HIP 98377 |
16.55 |
| 2026-06-17 00:00 |
20:00:11.89 |
+11:25:26.4 |
HIP 98377 |
16.30 |
| 2026-06-17 12:00 |
20:00:10.63 |
+11:25:29.4 |
HIP 98377 |
16.04 |
| 2026-06-18 00:00 |
20:00:09.36 |
+11:25:32.3 |
HIP 98377 |
15.79 |
| 2026-06-18 12:00 |
20:00:08.08 |
+11:25:35.1 |
HIP 98377 |
15.53 |
| 2026-06-19 00:00 |
20:00:06.80 |
+11:25:37.8 |
HIP 98377 |
15.27 |
| 2026-06-19 12:00 |
20:00:05.51 |
+11:25:40.4 |
HIP 98377 |
15.02 |
| 2026-06-20 00:00 |
20:00:04.21 |
+11:25:42.8 |
HIP 98377 |
14.76 |
| 2026-06-20 12:00 |
20:00:02.91 |
+11:25:45.2 |
HIP 98377 |
14.51 |
| 2026-06-21 00:00 |
20:00:01.60 |
+11:25:47.5 |
HIP 98377 |
14.25 |
| 2026-06-21 12:00 |
20:00:00.28 |
+11:25:49.6 |
HIP 98377 |
14.00 |
| 2026-06-22 00:00 |
19:59:58.96 |
+11:25:51.7 |
HIP 98377 |
13.74 |