メタデータ
| 項目 |
値 |
| Designation |
C/1979 Y1 (Bradfield) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1979-12-21T14:38:01.069440Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:29Z |
| Obs used |
127 |
| NEO |
- |
| M1 |
8.500 |
| K1 |
14.000 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
1980-01-25.0000000 |
| e |
0.98803814 |
| q (au) |
0.545301 |
| a (au) |
45.586646 |
| i (deg) |
148.602533 |
| Ω (om, deg) |
103.215535 |
| ω (w, deg) |
257.609730 |
| M (ma, deg) |
0.110124 |
等級
散乱 + 全体線形
$$
M_a = (8.331 + 4.383\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
8.331 |
| n |
4.383 |
| gf |
0.800 |
| gb |
-1.000 |
| k |
0.800 |
| 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 |
| 1979-12-26 |
1980-01-04 |
+1.4679 |
-0.064 |
| 1980-01-04 |
1980-01-25 |
+5.5414 |
+0.963 |
| 1980-01-25 |
1980-03-02 |
-4.9082 |
+0.307 |
| 1980-03-02 |
1980-03-17 |
-4.0819 |
-0.038 |
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 |
01:23:15.97 |
+40:19:07.6 |
HIP 6469 |
17.51 |
| 2026-05-12 12:00 |
01:23:18.01 |
+40:19:22.7 |
HIP 6469 |
17.27 |
| 2026-05-13 00:00 |
01:23:20.04 |
+40:19:38.0 |
HIP 6469 |
17.05 |
| 2026-05-13 12:00 |
01:23:22.06 |
+40:19:53.3 |
HIP 6469 |
16.83 |
| 2026-05-14 00:00 |
01:23:24.07 |
+40:20:08.6 |
HIP 6469 |
16.62 |
| 2026-05-14 12:00 |
01:23:26.08 |
+40:20:24.1 |
HIP 6469 |
16.42 |
| 2026-05-15 00:00 |
01:23:28.07 |
+40:20:39.6 |
HIP 6469 |
16.23 |
| 2026-05-15 12:00 |
01:23:30.05 |
+40:20:55.2 |
HIP 6469 |
16.04 |
| 2026-05-16 00:00 |
01:23:32.02 |
+40:21:10.9 |
HIP 6469 |
15.87 |
| 2026-05-16 12:00 |
01:23:33.98 |
+40:21:26.6 |
HIP 6469 |
15.70 |
| 2026-05-17 00:00 |
01:23:35.93 |
+40:21:42.4 |
HIP 6469 |
15.55 |
| 2026-05-17 12:00 |
01:23:37.87 |
+40:21:58.2 |
HIP 6469 |
15.41 |
| 2026-05-18 00:00 |
01:23:39.80 |
+40:22:14.1 |
HIP 6469 |
15.27 |
| 2026-05-18 12:00 |
01:23:41.72 |
+40:22:30.1 |
HIP 6469 |
15.15 |
| 2026-05-19 00:00 |
01:23:43.63 |
+40:22:46.2 |
HIP 6469 |
15.04 |
| 2026-05-19 12:00 |
01:23:45.53 |
+40:23:02.3 |
HIP 6469 |
14.94 |
| 2026-05-20 00:00 |
01:23:47.41 |
+40:23:18.4 |
HIP 6469 |
14.85 |
| 2026-05-20 12:00 |
01:23:49.28 |
+40:23:34.6 |
HIP 6469 |
14.77 |
| 2026-05-21 00:00 |
01:23:51.15 |
+40:23:50.9 |
HIP 6469 |
14.70 |
| 2026-05-21 12:00 |
01:23:53.00 |
+40:24:07.2 |
HIP 6469 |
14.65 |
| 2026-05-22 00:00 |
01:23:54.83 |
+40:24:23.6 |
HIP 6469 |
14.60 |
| 2026-05-22 12:00 |
01:23:56.66 |
+40:24:40.1 |
HIP 6469 |
14.57 |
| 2026-05-23 00:00 |
01:23:58.47 |
+40:24:56.5 |
HIP 6469 |
14.55 |
| 2026-05-23 12:00 |
01:24:00.27 |
+40:25:13.1 |
HIP 6469 |
14.54 |
| 2026-05-24 00:00 |
01:24:02.06 |
+40:25:29.7 |
HIP 6469 |
14.54 |
| 2026-05-24 12:00 |
01:24:03.84 |
+40:25:46.3 |
HIP 6469 |
14.55 |
| 2026-05-25 00:00 |
01:24:05.60 |
+40:26:03.0 |
HIP 6469 |
14.57 |
| 2026-05-25 12:00 |
01:24:07.35 |
+40:26:19.7 |
HIP 6469 |
14.60 |
| 2026-05-26 00:00 |
01:24:09.09 |
+40:26:36.5 |
HIP 6469 |
14.65 |
| 2026-05-26 12:00 |
01:24:10.82 |
+40:26:53.3 |
HIP 6469 |
14.70 |
| 2026-05-27 00:00 |
01:24:12.53 |
+40:27:10.2 |
HIP 6469 |
14.76 |
| 2026-05-27 12:00 |
01:24:14.23 |
+40:27:27.1 |
HIP 6469 |
14.84 |
| 2026-05-28 00:00 |
01:24:15.91 |
+40:27:44.0 |
HIP 6469 |
14.92 |
| 2026-05-28 12:00 |
01:24:17.58 |
+40:28:01.0 |
HIP 6469 |
15.01 |
| 2026-05-29 00:00 |
01:24:19.24 |
+40:28:18.0 |
HIP 6469 |
15.11 |
| 2026-05-29 12:00 |
01:24:20.89 |
+40:28:35.0 |
HIP 6469 |
15.22 |
| 2026-05-30 00:00 |
01:24:22.52 |
+40:28:52.1 |
HIP 6469 |
15.34 |
| 2026-05-30 12:00 |
01:24:24.14 |
+40:29:09.3 |
HIP 6469 |
15.46 |
| 2026-05-31 00:00 |
01:24:25.74 |
+40:29:26.4 |
HIP 6469 |
15.60 |
| 2026-05-31 12:00 |
01:24:27.33 |
+40:29:43.6 |
HIP 6469 |
15.74 |
| 2026-06-01 00:00 |
01:24:28.91 |
+40:30:00.8 |
HIP 6469 |
15.89 |
| 2026-06-01 12:00 |
01:24:30.47 |
+40:30:18.1 |
HIP 6469 |
16.04 |
| 2026-06-02 00:00 |
01:24:32.01 |
+40:30:35.4 |
HIP 6469 |
16.20 |