C/1980 Y1 (Bradfield)
メタデータ
| 項目 | 値 |
|---|---|
| Designation | C/1980 Y1 (Bradfield) |
| Type | C |
| Perihelion (tp_cal, UTC) | 1980-12-29T12:59:59.372160Z |
| Orbit solution date (soln_date, UTC) | 2021-04-15T23:29:29Z |
| Obs used | 32 |
| NEO | - |
| M1 | - |
| K1 | - |
| PC | 0.030 |
オスキュレーティング軌道要素
| 項目 | 値 |
|---|---|
| Epoch (epoch_cal, TDB) | 1981-01-26.0000000 |
| e | 0.99972538 |
| q (au) | 0.259823 |
| a (au) | 946.110211 |
| i (deg) | 138.585179 |
| Ω (om, deg) | 115.351543 |
| ω (w, deg) | 358.294122 |
| M (ma, deg) | 0.000930 |
等級
散乱 + 全体線形
$$ M_a = (7.110 + 2.589\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
モデル定数
| 項目 | 値 |
|---|---|
| H0 | 7.110 |
| n | 2.589 |
| gf | 0.800 |
| gb | -0.500 |
| k | 0.800 |
| 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 |
|---|---|---|---|
| 1981-01-04 | 1981-01-13 | -4.7670 | -1.473 |
| 1981-01-13 | 1981-01-31 | +3.4551 | +0.349 |
| 1981-01-31 | 1981-08-27 | +10.1983 | +0.293 |
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) |
|---|---|---|---|---|
| 2026-03-26 00:00 | 20:13:46.00 | -14:10:05.7 | HIP 99690 | 1.71 |
| 2026-03-26 12:00 | 20:13:46.75 | -14:10:01.2 | HIP 99690 | 1.82 |
| 2026-03-27 00:00 | 20:13:47.48 | -14:09:56.7 | HIP 99690 | 1.94 |
| 2026-03-27 12:00 | 20:13:48.21 | -14:09:52.2 | HIP 99690 | 2.07 |
| 2026-03-28 00:00 | 20:13:48.92 | -14:09:47.8 | HIP 99690 | 2.21 |
| 2026-03-28 12:00 | 20:13:49.61 | -14:09:43.5 | HIP 99690 | 2.35 |
| 2026-03-29 00:00 | 20:13:50.30 | -14:09:39.1 | HIP 99690 | 2.50 |
| 2026-03-29 12:00 | 20:13:50.97 | -14:09:34.8 | HIP 99690 | 2.65 |
| 2026-03-30 00:00 | 20:13:51.63 | -14:09:30.6 | HIP 99690 | 2.80 |
| 2026-03-30 12:00 | 20:13:52.27 | -14:09:26.3 | HIP 99690 | 2.95 |
| 2026-03-31 00:00 | 20:13:52.90 | -14:09:22.1 | HIP 99690 | 3.10 |
| 2026-03-31 12:00 | 20:13:53.52 | -14:09:18.0 | HIP 99690 | 3.24 |
| 2026-04-01 00:00 | 20:13:54.12 | -14:09:13.8 | HIP 99690 | 3.39 |
| 2026-04-01 12:00 | 20:13:54.72 | -14:09:09.7 | HIP 99690 | 3.54 |
| 2026-04-02 00:00 | 20:13:55.29 | -14:09:05.7 | HIP 99690 | 3.68 |
| 2026-04-02 12:00 | 20:13:55.86 | -14:09:01.7 | HIP 99690 | 3.83 |
| 2026-04-03 00:00 | 20:13:56.41 | -14:08:57.7 | HIP 99690 | 3.97 |
| 2026-04-03 12:00 | 20:13:56.94 | -14:08:53.7 | HIP 99690 | 4.10 |
| 2026-04-04 00:00 | 20:13:57.47 | -14:08:49.8 | HIP 99690 | 4.24 |
| 2026-04-04 12:00 | 20:13:57.98 | -14:08:46.0 | HIP 99690 | 4.37 |
| 2026-04-05 00:00 | 20:13:58.47 | -14:08:42.1 | HIP 99690 | 4.51 |
| 2026-04-05 12:00 | 20:13:58.95 | -14:08:38.3 | HIP 99690 | 4.63 |
| 2026-04-06 00:00 | 20:13:59.42 | -14:08:34.6 | HIP 99690 | 4.76 |
| 2026-04-06 12:00 | 20:13:59.87 | -14:08:30.9 | HIP 99690 | 4.88 |
| 2026-04-07 00:00 | 20:14:00.32 | -14:08:27.2 | HIP 99690 | 5.00 |
| 2026-04-07 12:00 | 20:14:00.74 | -14:08:23.5 | HIP 99690 | 5.12 |
| 2026-04-08 00:00 | 20:14:01.15 | -14:08:19.9 | HIP 99690 | 5.24 |
| 2026-04-08 12:00 | 20:14:01.55 | -14:08:16.4 | HIP 99690 | 5.35 |
| 2026-04-09 00:00 | 20:14:01.94 | -14:08:12.8 | HIP 99690 | 5.46 |
| 2026-04-09 12:00 | 20:14:02.31 | -14:08:09.4 | HIP 99690 | 5.56 |
| 2026-04-10 00:00 | 20:14:02.66 | -14:08:05.9 | HIP 99690 | 5.67 |
| 2026-04-10 12:00 | 20:14:03.01 | -14:08:02.5 | HIP 99690 | 5.76 |
| 2026-04-11 00:00 | 20:14:03.33 | -14:07:59.2 | HIP 99690 | 5.86 |
| 2026-04-11 12:00 | 20:14:03.65 | -14:07:55.9 | HIP 99690 | 5.96 |
| 2026-04-12 00:00 | 20:14:03.95 | -14:07:52.6 | HIP 99690 | 6.05 |
| 2026-04-12 12:00 | 20:14:04.23 | -14:07:49.3 | HIP 99690 | 6.13 |
| 2026-04-13 00:00 | 20:14:04.50 | -14:07:46.2 | HIP 99690 | 6.22 |
| 2026-04-13 12:00 | 20:14:04.76 | -14:07:43.0 | HIP 99690 | 6.30 |
| 2026-04-14 00:00 | 20:14:05.00 | -14:07:39.9 | HIP 99690 | 6.38 |
| 2026-04-14 12:00 | 20:14:05.23 | -14:07:36.8 | HIP 99690 | 6.45 |
| 2026-04-15 00:00 | 20:14:05.45 | -14:07:33.8 | HIP 99690 | 6.53 |
| 2026-04-15 12:00 | 20:14:05.65 | -14:07:30.9 | HIP 99690 | 6.59 |
| 2026-04-16 00:00 | 20:14:05.83 | -14:07:27.9 | HIP 99690 | 6.66 |