メタデータ
| 項目 |
値 |
| Designation |
C/2018 A1 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-10-20T10:16:17.644800Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:39Z |
| Obs used |
118 |
| NEO |
- |
| M1 |
15.100 |
| K1 |
5.000 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2018-02-06.0000000 |
| e |
0.90438598 |
| q (au) |
2.419351 |
| a (au) |
25.303307 |
| i (deg) |
53.559981 |
| Ω (om, deg) |
336.621053 |
| ω (w, deg) |
96.385267 |
| M (ma, deg) |
0.840729 |
等級
散乱 + 全体線形
$$
M_a = (16.981 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
16.981 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.738 |
| 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
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
11:44:03.86 |
-52:17:33.0 |
HIP 57197 |
11.96 |
| 2026-05-12 12:00 |
11:43:58.87 |
-52:16:26.8 |
HIP 57197 |
12.89 |
| 2026-05-13 00:00 |
11:43:53.94 |
-52:15:20.5 |
HIP 57142 |
13.43 |
| 2026-05-13 12:00 |
11:43:49.10 |
-52:14:13.9 |
HIP 57142 |
14.01 |
| 2026-05-14 00:00 |
11:43:44.32 |
-52:13:07.1 |
HIP 57142 |
14.69 |
| 2026-05-14 12:00 |
11:43:39.62 |
-52:12:00.2 |
HIP 57327 |
15.16 |
| 2026-05-15 00:00 |
11:43:35.00 |
-52:10:53.1 |
HIP 57327 |
15.70 |
| 2026-05-15 12:00 |
11:43:30.45 |
-52:09:45.9 |
HIP 57327 |
16.31 |
| 2026-05-16 00:00 |
11:43:25.98 |
-52:08:38.4 |
HIP 57327 |
17.00 |
| 2026-05-16 12:00 |
11:43:21.59 |
-52:07:30.9 |
HIP 57327 |
17.74 |
| 2026-05-17 00:00 |
11:43:17.27 |
-52:06:23.2 |
HIP 57157 |
17.24 |
| 2026-05-17 12:00 |
11:43:13.02 |
-52:05:15.3 |
HIP 57157 |
16.13 |
| 2026-05-18 00:00 |
11:43:08.85 |
-52:04:07.4 |
HIP 57157 |
15.06 |
| 2026-05-18 12:00 |
11:43:04.76 |
-52:02:59.3 |
HIP 57157 |
14.01 |
| 2026-05-19 00:00 |
11:43:00.75 |
-52:01:51.1 |
HIP 57157 |
13.01 |
| 2026-05-19 12:00 |
11:42:56.82 |
-52:00:42.8 |
HIP 57157 |
12.06 |
| 2026-05-20 00:00 |
11:42:52.96 |
-51:59:34.4 |
HIP 57157 |
11.17 |
| 2026-05-20 12:00 |
11:42:49.18 |
-51:58:25.9 |
HIP 57157 |
10.36 |
| 2026-05-21 00:00 |
11:42:45.47 |
-51:57:17.3 |
HIP 57157 |
9.65 |
| 2026-05-21 12:00 |
11:42:41.85 |
-51:56:08.7 |
HIP 57157 |
9.05 |
| 2026-05-22 00:00 |
11:42:38.30 |
-51:55:00.0 |
HIP 57157 |
8.59 |
| 2026-05-22 12:00 |
11:42:34.83 |
-51:53:51.2 |
HIP 57157 |
8.29 |
| 2026-05-23 00:00 |
11:42:31.44 |
-51:52:42.3 |
HIP 57157 |
8.17 |
| 2026-05-23 12:00 |
11:42:28.13 |
-51:51:33.4 |
HIP 57157 |
8.23 |
| 2026-05-24 00:00 |
11:42:24.90 |
-51:50:24.5 |
HIP 57157 |
8.46 |
| 2026-05-24 12:00 |
11:42:21.74 |
-51:49:15.5 |
HIP 57157 |
8.86 |
| 2026-05-25 00:00 |
11:42:18.66 |
-51:48:06.5 |
HIP 57157 |
9.39 |
| 2026-05-25 12:00 |
11:42:15.66 |
-51:46:57.5 |
HIP 57157 |
10.04 |
| 2026-05-26 00:00 |
11:42:12.74 |
-51:45:48.4 |
HIP 57157 |
10.78 |
| 2026-05-26 12:00 |
11:42:09.90 |
-51:44:39.4 |
HIP 57157 |
11.60 |
| 2026-05-27 00:00 |
11:42:07.13 |
-51:43:30.3 |
HIP 57157 |
12.47 |
| 2026-05-27 12:00 |
11:42:04.45 |
-51:42:21.2 |
HIP 57157 |
13.39 |
| 2026-05-28 00:00 |
11:42:01.84 |
-51:41:12.2 |
HIP 57157 |
14.35 |
| 2026-05-28 12:00 |
11:41:59.31 |
-51:40:03.2 |
HIP 57157 |
15.33 |
| 2026-05-29 00:00 |
11:41:56.86 |
-51:38:54.1 |
HIP 57157 |
16.34 |
| 2026-05-29 12:00 |
11:41:54.49 |
-51:37:45.1 |
HIP 57157 |
17.36 |
| 2026-05-30 00:00 |
11:41:52.19 |
-51:36:36.2 |
HIP 57157 |
18.40 |
| 2026-05-30 12:00 |
11:41:49.98 |
-51:35:27.2 |
HIP 57157 |
19.44 |
| 2026-05-31 00:00 |
11:41:47.84 |
-51:34:18.3 |
HIP 57157 |
20.50 |
| 2026-05-31 12:00 |
11:41:45.79 |
-51:33:09.5 |
HIP 57157 |
21.56 |
| 2026-06-01 00:00 |
11:41:43.81 |
-51:32:00.7 |
HIP 57157 |
22.62 |
| 2026-06-01 12:00 |
11:41:41.90 |
-51:30:52.0 |
HIP 56853 |
22.29 |
| 2026-06-02 00:00 |
11:41:40.08 |
-51:29:43.3 |
HIP 56853 |
21.77 |