メタデータ
| 項目 |
値 |
| Designation |
C/1989 A1 (Yanaka) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1988-10-31T19:17:00.879360Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:36Z |
| Obs used |
101 |
| NEO |
- |
| M1 |
5.700 |
| K1 |
16.000 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
1989-02-04.0000000 |
| e |
0.99863759 |
| q (au) |
1.894621 |
| a (au) |
1390.639657 |
| i (deg) |
52.409723 |
| Ω (om, deg) |
157.088675 |
| ω (w, deg) |
351.561502 |
| M (ma, deg) |
0.001809 |
等級
散乱 + 全体線形
$$
M_a = (4.241 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
4.241 |
| 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) |
| 2026-05-12 00:00 |
21:01:21.39 |
+06:16:28.8 |
HIP 104010 |
44.39 |
| 2026-05-12 12:00 |
21:01:21.20 |
+06:16:38.6 |
HIP 104010 |
44.44 |
| 2026-05-13 00:00 |
21:01:20.99 |
+06:16:48.3 |
HIP 104010 |
44.49 |
| 2026-05-13 12:00 |
21:01:20.76 |
+06:16:57.9 |
HIP 104010 |
44.55 |
| 2026-05-14 00:00 |
21:01:20.52 |
+06:17:07.5 |
HIP 104010 |
44.61 |
| 2026-05-14 12:00 |
21:01:20.26 |
+06:17:17.0 |
HIP 104010 |
44.68 |
| 2026-05-15 00:00 |
21:01:19.99 |
+06:17:26.4 |
HIP 104010 |
44.75 |
| 2026-05-15 12:00 |
21:01:19.70 |
+06:17:35.7 |
HIP 104010 |
44.82 |
| 2026-05-16 00:00 |
21:01:19.39 |
+06:17:44.9 |
HIP 104010 |
44.90 |
| 2026-05-16 12:00 |
21:01:19.07 |
+06:17:54.1 |
HIP 104010 |
44.99 |
| 2026-05-17 00:00 |
21:01:18.73 |
+06:18:03.2 |
HIP 104010 |
45.07 |
| 2026-05-17 12:00 |
21:01:18.38 |
+06:18:12.1 |
HIP 104010 |
45.17 |
| 2026-05-18 00:00 |
21:01:18.01 |
+06:18:21.1 |
HIP 104010 |
45.26 |
| 2026-05-18 12:00 |
21:01:17.63 |
+06:18:29.9 |
HIP 104010 |
45.36 |
| 2026-05-19 00:00 |
21:01:17.23 |
+06:18:38.6 |
HIP 104010 |
45.47 |
| 2026-05-19 12:00 |
21:01:16.82 |
+06:18:47.3 |
HIP 104010 |
45.58 |
| 2026-05-20 00:00 |
21:01:16.39 |
+06:18:55.8 |
HIP 104010 |
45.69 |
| 2026-05-20 12:00 |
21:01:15.94 |
+06:19:04.3 |
HIP 104010 |
45.81 |
| 2026-05-21 00:00 |
21:01:15.48 |
+06:19:12.7 |
HIP 104010 |
45.93 |
| 2026-05-21 12:00 |
21:01:15.01 |
+06:19:21.0 |
HIP 104010 |
46.06 |
| 2026-05-22 00:00 |
21:01:14.52 |
+06:19:29.3 |
HIP 104010 |
46.18 |
| 2026-05-22 12:00 |
21:01:14.01 |
+06:19:37.4 |
HIP 104010 |
46.32 |
| 2026-05-23 00:00 |
21:01:13.49 |
+06:19:45.4 |
HIP 104010 |
46.46 |
| 2026-05-23 12:00 |
21:01:12.95 |
+06:19:53.4 |
HIP 104010 |
46.60 |
| 2026-05-24 00:00 |
21:01:12.40 |
+06:20:01.2 |
HIP 104010 |
46.74 |
| 2026-05-24 12:00 |
21:01:11.84 |
+06:20:09.0 |
HIP 104010 |
46.89 |
| 2026-05-25 00:00 |
21:01:11.26 |
+06:20:16.7 |
HIP 104010 |
47.05 |
| 2026-05-25 12:00 |
21:01:10.66 |
+06:20:24.3 |
HIP 104010 |
47.20 |
| 2026-05-26 00:00 |
21:01:10.05 |
+06:20:31.8 |
HIP 104010 |
47.36 |
| 2026-05-26 12:00 |
21:01:09.43 |
+06:20:39.2 |
HIP 104010 |
47.53 |
| 2026-05-27 00:00 |
21:01:08.79 |
+06:20:46.5 |
HIP 104010 |
47.70 |
| 2026-05-27 12:00 |
21:01:08.13 |
+06:20:53.7 |
HIP 104010 |
47.87 |
| 2026-05-28 00:00 |
21:01:07.46 |
+06:21:00.8 |
HIP 104010 |
48.05 |
| 2026-05-28 12:00 |
21:01:06.78 |
+06:21:07.8 |
HIP 104010 |
48.23 |
| 2026-05-29 00:00 |
21:01:06.08 |
+06:21:14.7 |
HIP 103649 |
48.31 |
| 2026-05-29 12:00 |
21:01:05.37 |
+06:21:21.6 |
HIP 103649 |
48.36 |
| 2026-05-30 00:00 |
21:01:04.65 |
+06:21:28.3 |
HIP 103649 |
48.41 |
| 2026-05-30 12:00 |
21:01:03.90 |
+06:21:34.9 |
HIP 103649 |
48.46 |
| 2026-05-31 00:00 |
21:01:03.15 |
+06:21:41.5 |
HIP 103649 |
48.50 |
| 2026-05-31 12:00 |
21:01:02.38 |
+06:21:47.9 |
HIP 103649 |
48.55 |
| 2026-06-01 00:00 |
21:01:01.60 |
+06:21:54.2 |
HIP 103649 |
48.59 |
| 2026-06-01 12:00 |
21:01:00.80 |
+06:22:00.5 |
HIP 103649 |
48.63 |
| 2026-06-02 00:00 |
21:00:59.99 |
+06:22:06.6 |
HIP 103649 |
48.66 |