メタデータ
| 項目 |
値 |
| Designation |
C/2018 A3 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2019-01-12T20:43:26.261760Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:39Z |
| Obs used |
1589 |
| NEO |
- |
| M1 |
9.400 |
| K1 |
9.000 |
| PC |
0.030 |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2018-12-07.0000000 |
| e |
0.99339311 |
| q (au) |
3.276715 |
| a (au) |
495.953962 |
| i (deg) |
139.561983 |
| Ω (om, deg) |
194.279275 |
| ω (w, deg) |
86.426299 |
| M (ma, deg) |
359.996710 |
等級
散乱 + 全体線形
$$
M_a = (10.483 + 3.261\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
10.483 |
| n |
3.261 |
| gf |
0.999 |
| gb |
-0.500 |
| k |
0.800 |
| δ90 |
3.469 |
| 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
残差 (区間線形)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| 開始日 (UTC) |
終了日 (UTC) |
a |
b |
| 2018-01-10 |
2019-01-12 |
+0.8638 |
-0.847 |
| 2019-01-12 |
2019-10-05 |
-2.0619 |
+1.339 |
| 2019-10-05 |
2020-10-24 |
+4.9810 |
-2.845 |
log10 r = log10(太陽距離/AU)、Δ = 地球距離(AU)
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
23:52:13.88 |
-25:24:58.2 |
HIP 117796 |
22.27 |
| 2026-05-12 12:00 |
23:52:17.19 |
-25:25:20.8 |
HIP 117796 |
21.49 |
| 2026-05-13 00:00 |
23:52:20.45 |
-25:25:43.9 |
HIP 117796 |
20.72 |
| 2026-05-13 12:00 |
23:52:23.67 |
-25:26:07.4 |
HIP 117796 |
19.95 |
| 2026-05-14 00:00 |
23:52:26.85 |
-25:26:31.4 |
HIP 117796 |
19.18 |
| 2026-05-14 12:00 |
23:52:29.99 |
-25:26:55.8 |
HIP 117796 |
18.42 |
| 2026-05-15 00:00 |
23:52:33.08 |
-25:27:20.6 |
HIP 117796 |
17.66 |
| 2026-05-15 12:00 |
23:52:36.13 |
-25:27:45.9 |
HIP 117796 |
16.91 |
| 2026-05-16 00:00 |
23:52:39.14 |
-25:28:11.6 |
HIP 117796 |
16.17 |
| 2026-05-16 12:00 |
23:52:42.11 |
-25:28:37.8 |
HIP 117796 |
15.43 |
| 2026-05-17 00:00 |
23:52:45.03 |
-25:29:04.3 |
HIP 117796 |
14.69 |
| 2026-05-17 12:00 |
23:52:47.90 |
-25:29:31.4 |
HIP 117796 |
13.96 |
| 2026-05-18 00:00 |
23:52:50.73 |
-25:29:58.8 |
HIP 117796 |
13.24 |
| 2026-05-18 12:00 |
23:52:53.52 |
-25:30:26.7 |
HIP 117796 |
12.52 |
| 2026-05-19 00:00 |
23:52:56.26 |
-25:30:55.0 |
HIP 117796 |
11.81 |
| 2026-05-19 12:00 |
23:52:58.96 |
-25:31:23.8 |
HIP 117796 |
11.11 |
| 2026-05-20 00:00 |
23:53:01.61 |
-25:31:52.9 |
HIP 117796 |
10.41 |
| 2026-05-20 12:00 |
23:53:04.22 |
-25:32:22.5 |
HIP 117796 |
9.72 |
| 2026-05-21 00:00 |
23:53:06.78 |
-25:32:52.6 |
HIP 117796 |
9.05 |
| 2026-05-21 12:00 |
23:53:09.29 |
-25:33:23.0 |
HIP 117796 |
8.38 |
| 2026-05-22 00:00 |
23:53:11.76 |
-25:33:53.9 |
HIP 117796 |
7.73 |
| 2026-05-22 12:00 |
23:53:14.18 |
-25:34:25.2 |
HIP 117796 |
7.09 |
| 2026-05-23 00:00 |
23:53:16.55 |
-25:34:57.0 |
HIP 117796 |
6.48 |
| 2026-05-23 12:00 |
23:53:18.88 |
-25:35:29.1 |
HIP 117796 |
5.89 |
| 2026-05-24 00:00 |
23:53:21.16 |
-25:36:01.7 |
HIP 117796 |
5.33 |
| 2026-05-24 12:00 |
23:53:23.39 |
-25:36:34.7 |
HIP 117796 |
4.81 |
| 2026-05-25 00:00 |
23:53:25.58 |
-25:37:08.1 |
HIP 117796 |
4.36 |
| 2026-05-25 12:00 |
23:53:27.71 |
-25:37:42.0 |
HIP 117796 |
3.98 |
| 2026-05-26 00:00 |
23:53:29.80 |
-25:38:16.2 |
HIP 117796 |
3.70 |
| 2026-05-26 12:00 |
23:53:31.85 |
-25:38:50.9 |
HIP 117796 |
3.54 |
| 2026-05-27 00:00 |
23:53:33.84 |
-25:39:25.9 |
HIP 117796 |
3.52 |
| 2026-05-27 12:00 |
23:53:35.78 |
-25:40:01.4 |
HIP 117796 |
3.63 |
| 2026-05-28 00:00 |
23:53:37.68 |
-25:40:37.3 |
HIP 117796 |
3.88 |
| 2026-05-28 12:00 |
23:53:39.53 |
-25:41:13.6 |
HIP 117796 |
4.23 |
| 2026-05-29 00:00 |
23:53:41.32 |
-25:41:50.4 |
HIP 117796 |
4.65 |
| 2026-05-29 12:00 |
23:53:43.07 |
-25:42:27.5 |
HIP 117796 |
5.14 |
| 2026-05-30 00:00 |
23:53:44.77 |
-25:43:05.0 |
HIP 117796 |
5.68 |
| 2026-05-30 12:00 |
23:53:46.42 |
-25:43:42.9 |
HIP 117796 |
6.24 |
| 2026-05-31 00:00 |
23:53:48.02 |
-25:44:21.3 |
HIP 117796 |
6.83 |
| 2026-05-31 12:00 |
23:53:49.57 |
-25:45:00.0 |
HIP 117796 |
7.44 |
| 2026-06-01 00:00 |
23:53:51.07 |
-25:45:39.2 |
HIP 117796 |
8.06 |
| 2026-06-01 12:00 |
23:53:52.52 |
-25:46:18.7 |
HIP 117796 |
8.70 |
| 2026-06-02 00:00 |
23:53:53.92 |
-25:46:58.6 |
HIP 117796 |
9.35 |