メタデータ
| 項目 |
値 |
| Designation |
C/1989 A6 (Shoemaker) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1988-11-02T02:05:44.491200Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:38Z |
| Obs used |
28 |
| NEO |
- |
| M1 |
13.300 |
| K1 |
4.500 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
1989-02-10.0000000 |
| e |
1.00000000 |
| q (au) |
2.207946 |
| a (au) |
- |
| i (deg) |
25.505596 |
| Ω (om, deg) |
74.314457 |
| ω (w, deg) |
18.838143 |
| M (ma, deg) |
- |
等級
散乱 + 全体線形
$$
M_a = (11.985 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
11.985 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.502 |
| 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 |
16:42:27.71 |
-20:53:59.6 |
HIP 81887 |
20.40 |
| 2026-05-12 12:00 |
16:42:25.83 |
-20:53:56.3 |
HIP 81887 |
20.72 |
| 2026-05-13 00:00 |
16:42:23.95 |
-20:53:53.0 |
HIP 81887 |
21.05 |
| 2026-05-13 12:00 |
16:42:22.06 |
-20:53:49.7 |
HIP 81887 |
21.38 |
| 2026-05-14 00:00 |
16:42:20.17 |
-20:53:46.3 |
HIP 81887 |
21.72 |
| 2026-05-14 12:00 |
16:42:18.27 |
-20:53:43.0 |
HIP 81887 |
22.06 |
| 2026-05-15 00:00 |
16:42:16.37 |
-20:53:39.7 |
HIP 81887 |
22.41 |
| 2026-05-15 12:00 |
16:42:14.46 |
-20:53:36.3 |
HIP 81887 |
22.76 |
| 2026-05-16 00:00 |
16:42:12.54 |
-20:53:33.0 |
HIP 81887 |
23.11 |
| 2026-05-16 12:00 |
16:42:10.62 |
-20:53:29.6 |
HIP 81887 |
23.47 |
| 2026-05-17 00:00 |
16:42:08.69 |
-20:53:26.2 |
HIP 81887 |
23.84 |
| 2026-05-17 12:00 |
16:42:06.76 |
-20:53:22.9 |
HIP 81887 |
24.20 |
| 2026-05-18 00:00 |
16:42:04.82 |
-20:53:19.5 |
HIP 81887 |
24.58 |
| 2026-05-18 12:00 |
16:42:02.88 |
-20:53:16.1 |
HIP 81887 |
24.95 |
| 2026-05-19 00:00 |
16:42:00.94 |
-20:53:12.7 |
HIP 81887 |
25.33 |
| 2026-05-19 12:00 |
16:41:58.98 |
-20:53:09.4 |
HIP 81887 |
25.71 |
| 2026-05-20 00:00 |
16:41:57.03 |
-20:53:06.0 |
HIP 81887 |
26.10 |
| 2026-05-20 12:00 |
16:41:55.07 |
-20:53:02.6 |
HIP 81887 |
26.49 |
| 2026-05-21 00:00 |
16:41:53.11 |
-20:52:59.2 |
HIP 81887 |
26.88 |
| 2026-05-21 12:00 |
16:41:51.14 |
-20:52:55.8 |
HIP 81887 |
27.28 |
| 2026-05-22 00:00 |
16:41:49.17 |
-20:52:52.4 |
HIP 81887 |
27.68 |
| 2026-05-22 12:00 |
16:41:47.20 |
-20:52:49.0 |
HIP 81887 |
28.08 |
| 2026-05-23 00:00 |
16:41:45.23 |
-20:52:45.6 |
HIP 81887 |
28.48 |
| 2026-05-23 12:00 |
16:41:43.25 |
-20:52:42.2 |
HIP 81887 |
28.89 |
| 2026-05-24 00:00 |
16:41:41.26 |
-20:52:38.8 |
HIP 81887 |
29.30 |
| 2026-05-24 12:00 |
16:41:39.28 |
-20:52:35.3 |
HIP 81887 |
29.71 |
| 2026-05-25 00:00 |
16:41:37.29 |
-20:52:31.9 |
HIP 81887 |
30.12 |
| 2026-05-25 12:00 |
16:41:35.30 |
-20:52:28.5 |
HIP 81887 |
30.53 |
| 2026-05-26 00:00 |
16:41:33.31 |
-20:52:25.1 |
HIP 81887 |
30.95 |
| 2026-05-26 12:00 |
16:41:31.31 |
-20:52:21.7 |
HIP 81632 |
30.85 |
| 2026-05-27 00:00 |
16:41:29.32 |
-20:52:18.3 |
HIP 81632 |
30.60 |
| 2026-05-27 12:00 |
16:41:27.32 |
-20:52:14.9 |
HIP 81632 |
30.35 |
| 2026-05-28 00:00 |
16:41:25.32 |
-20:52:11.5 |
HIP 81632 |
30.11 |
| 2026-05-28 12:00 |
16:41:23.32 |
-20:52:08.1 |
HIP 81632 |
29.88 |
| 2026-05-29 00:00 |
16:41:21.32 |
-20:52:04.7 |
HIP 81632 |
29.65 |
| 2026-05-29 12:00 |
16:41:19.31 |
-20:52:01.3 |
HIP 81632 |
29.43 |
| 2026-05-30 00:00 |
16:41:17.31 |
-20:51:57.9 |
HIP 81632 |
29.21 |
| 2026-05-30 12:00 |
16:41:15.30 |
-20:51:54.5 |
HIP 81632 |
29.00 |
| 2026-05-31 00:00 |
16:41:13.29 |
-20:51:51.1 |
HIP 81632 |
28.80 |
| 2026-05-31 12:00 |
16:41:11.28 |
-20:51:47.7 |
HIP 81632 |
28.60 |
| 2026-06-01 00:00 |
16:41:09.28 |
-20:51:44.3 |
HIP 81632 |
28.40 |
| 2026-06-01 12:00 |
16:41:07.27 |
-20:51:40.9 |
HIP 81632 |
28.22 |
| 2026-06-02 00:00 |
16:41:05.26 |
-20:51:37.5 |
HIP 81632 |
28.04 |