メタデータ
| 項目 |
値 |
| Designation |
C/2018 A4 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2018-05-18T19:21:20.165760Z |
| Orbit solution date (soln_date, UTC) |
2023-05-03T22:42:49Z |
| Obs used |
79 |
| NEO |
- |
| M1 |
8.400 |
| K1 |
22.250 |
| PC |
0.030 |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2018-01-15.0000000 |
| e |
0.80435873 |
| q (au) |
2.402567 |
| a (au) |
12.280471 |
| i (deg) |
3.148025 |
| Ω (om, deg) |
97.634759 |
| ω (w, deg) |
356.135345 |
| M (ma, deg) |
357.164531 |
等級
散乱 + 全体線形
$$
M_a = (10.546 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
10.546 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| 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) |
| 2026-07-29 00:00 |
16:14:46.16 |
-19:37:44.4 |
HIP 79439 |
29.73 |
| 2026-07-29 12:00 |
16:14:43.38 |
-19:37:40.9 |
HIP 79439 |
29.09 |
| 2026-07-30 00:00 |
16:14:40.67 |
-19:37:37.6 |
HIP 79439 |
28.45 |
| 2026-07-30 12:00 |
16:14:38.01 |
-19:37:34.4 |
HIP 79439 |
27.83 |
| 2026-07-31 00:00 |
16:14:35.41 |
-19:37:31.3 |
HIP 79439 |
27.23 |
| 2026-07-31 12:00 |
16:14:32.88 |
-19:37:28.4 |
HIP 79439 |
26.65 |
| 2026-08-01 00:00 |
16:14:30.41 |
-19:37:25.7 |
HIP 79439 |
26.07 |
| 2026-08-01 12:00 |
16:14:28.00 |
-19:37:23.2 |
HIP 79439 |
25.52 |
| 2026-08-02 00:00 |
16:14:25.65 |
-19:37:20.8 |
HIP 79439 |
24.98 |
| 2026-08-02 12:00 |
16:14:23.37 |
-19:37:18.6 |
HIP 79439 |
24.45 |
| 2026-08-03 00:00 |
16:14:21.15 |
-19:37:16.5 |
HIP 79439 |
23.94 |
| 2026-08-03 12:00 |
16:14:18.99 |
-19:37:14.6 |
HIP 79439 |
23.44 |
| 2026-08-04 00:00 |
16:14:16.89 |
-19:37:12.9 |
HIP 79439 |
22.97 |
| 2026-08-04 12:00 |
16:14:14.86 |
-19:37:11.4 |
HIP 79439 |
22.50 |
| 2026-08-05 00:00 |
16:14:12.89 |
-19:37:10.0 |
HIP 79439 |
22.05 |
| 2026-08-05 12:00 |
16:14:10.98 |
-19:37:08.8 |
HIP 79439 |
21.62 |
| 2026-08-06 00:00 |
16:14:09.14 |
-19:37:07.7 |
HIP 79439 |
21.21 |
| 2026-08-06 12:00 |
16:14:07.36 |
-19:37:06.8 |
HIP 79439 |
20.81 |
| 2026-08-07 00:00 |
16:14:05.65 |
-19:37:06.1 |
HIP 79439 |
20.42 |
| 2026-08-07 12:00 |
16:14:03.99 |
-19:37:05.5 |
HIP 79439 |
20.05 |
| 2026-08-08 00:00 |
16:14:02.41 |
-19:37:05.1 |
HIP 79439 |
19.70 |
| 2026-08-08 12:00 |
16:14:00.89 |
-19:37:04.9 |
HIP 79439 |
19.36 |
| 2026-08-09 00:00 |
16:13:59.43 |
-19:37:04.9 |
HIP 79439 |
19.04 |
| 2026-08-09 12:00 |
16:13:58.03 |
-19:37:05.0 |
HIP 79439 |
18.74 |
| 2026-08-10 00:00 |
16:13:56.71 |
-19:37:05.3 |
HIP 79439 |
18.45 |
| 2026-08-10 12:00 |
16:13:55.44 |
-19:37:05.8 |
HIP 79439 |
18.18 |
| 2026-08-11 00:00 |
16:13:54.24 |
-19:37:06.4 |
HIP 79439 |
17.92 |
| 2026-08-11 12:00 |
16:13:53.11 |
-19:37:07.2 |
HIP 79439 |
17.68 |
| 2026-08-12 00:00 |
16:13:52.04 |
-19:37:08.1 |
HIP 79439 |
17.45 |
| 2026-08-12 12:00 |
16:13:51.04 |
-19:37:09.3 |
HIP 79439 |
17.25 |
| 2026-08-13 00:00 |
16:13:50.10 |
-19:37:10.6 |
HIP 79439 |
17.05 |
| 2026-08-13 12:00 |
16:13:49.23 |
-19:37:12.1 |
HIP 79439 |
16.88 |
| 2026-08-14 00:00 |
16:13:48.42 |
-19:37:13.7 |
HIP 79439 |
16.71 |
| 2026-08-14 12:00 |
16:13:47.68 |
-19:37:15.5 |
HIP 79439 |
16.57 |
| 2026-08-15 00:00 |
16:13:47.00 |
-19:37:17.5 |
HIP 79439 |
16.44 |
| 2026-08-15 12:00 |
16:13:46.39 |
-19:37:19.6 |
HIP 79439 |
16.33 |
| 2026-08-16 00:00 |
16:13:45.85 |
-19:37:22.0 |
HIP 79439 |
16.23 |
| 2026-08-16 12:00 |
16:13:45.37 |
-19:37:24.5 |
HIP 79439 |
16.15 |
| 2026-08-17 00:00 |
16:13:44.95 |
-19:37:27.1 |
HIP 79439 |
16.08 |
| 2026-08-17 12:00 |
16:13:44.60 |
-19:37:29.9 |
HIP 79439 |
16.03 |
| 2026-08-18 00:00 |
16:13:44.32 |
-19:37:32.9 |
HIP 79439 |
15.99 |
| 2026-08-18 12:00 |
16:13:44.10 |
-19:37:36.1 |
HIP 79439 |
15.97 |
| 2026-08-19 00:00 |
16:13:43.95 |
-19:37:39.4 |
HIP 79439 |
15.96 |