C/2018 A4 (PANSTARRS)
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
$$
M_a = (10.536 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
10.536 |
| 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) |
| 2026-02-03 00:00 |
16:35:46.16 |
-20:27:06.3 |
HIP 81287 |
16.74 |
| 2026-02-03 12:00 |
16:35:50.79 |
-20:27:13.6 |
HIP 81287 |
16.30 |
| 2026-02-04 00:00 |
16:35:55.36 |
-20:27:20.8 |
HIP 81287 |
15.92 |
| 2026-02-04 12:00 |
16:35:59.87 |
-20:27:27.9 |
HIP 81287 |
15.62 |
| 2026-02-05 00:00 |
16:36:04.33 |
-20:27:34.8 |
HIP 81287 |
15.39 |
| 2026-02-05 12:00 |
16:36:08.72 |
-20:27:41.6 |
HIP 81287 |
15.23 |
| 2026-02-06 00:00 |
16:36:13.05 |
-20:27:48.2 |
HIP 81287 |
15.15 |
| 2026-02-06 12:00 |
16:36:17.32 |
-20:27:54.7 |
HIP 81287 |
15.13 |
| 2026-02-07 00:00 |
16:36:21.53 |
-20:28:01.1 |
HIP 81287 |
15.17 |
| 2026-02-07 12:00 |
16:36:25.69 |
-20:28:07.3 |
HIP 81287 |
15.28 |
| 2026-02-08 00:00 |
16:36:29.77 |
-20:28:13.3 |
HIP 81287 |
15.45 |
| 2026-02-08 12:00 |
16:36:33.80 |
-20:28:19.3 |
HIP 81287 |
15.67 |
| 2026-02-09 00:00 |
16:36:37.77 |
-20:28:25.1 |
HIP 81287 |
15.95 |
| 2026-02-09 12:00 |
16:36:41.67 |
-20:28:30.7 |
HIP 81287 |
16.26 |
| 2026-02-10 00:00 |
16:36:45.51 |
-20:28:36.2 |
HIP 81287 |
16.62 |
| 2026-02-10 12:00 |
16:36:49.29 |
-20:28:41.5 |
HIP 81287 |
17.01 |
| 2026-02-11 00:00 |
16:36:53.01 |
-20:28:46.7 |
HIP 81287 |
17.43 |
| 2026-02-11 12:00 |
16:36:56.66 |
-20:28:51.8 |
HIP 81287 |
17.88 |
| 2026-02-12 00:00 |
16:37:00.25 |
-20:28:56.7 |
HIP 81287 |
18.35 |
| 2026-02-12 12:00 |
16:37:03.77 |
-20:29:01.5 |
HIP 81287 |
18.83 |
| 2026-02-13 00:00 |
16:37:07.23 |
-20:29:06.2 |
HIP 81287 |
19.33 |
| 2026-02-13 12:00 |
16:37:10.63 |
-20:29:10.6 |
HIP 81287 |
19.84 |
| 2026-02-14 00:00 |
16:37:13.96 |
-20:29:15.0 |
HIP 81287 |
20.36 |
| 2026-02-14 12:00 |
16:37:17.22 |
-20:29:19.2 |
HIP 81287 |
20.89 |
| 2026-02-15 00:00 |
16:37:20.42 |
-20:29:23.3 |
HIP 81287 |
21.42 |
| 2026-02-15 12:00 |
16:37:23.56 |
-20:29:27.2 |
HIP 81287 |
21.95 |
| 2026-02-16 00:00 |
16:37:26.63 |
-20:29:30.9 |
HIP 81287 |
22.49 |
| 2026-02-16 12:00 |
16:37:29.63 |
-20:29:34.6 |
HIP 81287 |
23.02 |
| 2026-02-17 00:00 |
16:37:32.56 |
-20:29:38.1 |
HIP 81287 |
23.55 |
| 2026-02-17 12:00 |
16:37:35.43 |
-20:29:41.4 |
HIP 81287 |
24.08 |
| 2026-02-18 00:00 |
16:37:38.24 |
-20:29:44.6 |
HIP 81287 |
24.60 |
| 2026-02-18 12:00 |
16:37:40.97 |
-20:29:47.6 |
HIP 81287 |
25.12 |
| 2026-02-19 00:00 |
16:37:43.64 |
-20:29:50.5 |
HIP 81287 |
25.63 |
| 2026-02-19 12:00 |
16:37:46.24 |
-20:29:53.3 |
HIP 81287 |
26.13 |
| 2026-02-20 00:00 |
16:37:48.78 |
-20:29:55.9 |
HIP 81287 |
26.62 |
| 2026-02-20 12:00 |
16:37:51.24 |
-20:29:58.4 |
HIP 81287 |
27.11 |
| 2026-02-21 00:00 |
16:37:53.64 |
-20:30:00.7 |
HIP 81287 |
27.58 |
| 2026-02-21 12:00 |
16:37:55.97 |
-20:30:02.9 |
HIP 81287 |
28.05 |
| 2026-02-22 00:00 |
16:37:58.23 |
-20:30:05.0 |
HIP 81287 |
28.50 |
| 2026-02-22 12:00 |
16:38:00.42 |
-20:30:06.9 |
HIP 81287 |
28.95 |
| 2026-02-23 00:00 |
16:38:02.55 |
-20:30:08.7 |
HIP 81287 |
29.38 |
| 2026-02-23 12:00 |
16:38:04.60 |
-20:30:10.3 |
HIP 81287 |
29.81 |
| 2026-02-24 00:00 |
16:38:06.59 |
-20:30:11.8 |
HIP 81325 |
30.17 |