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
$$
M_a = (10.483 + 3.260\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
10.483 |
| n |
3.260 |
| gf |
0.990 |
| gb |
-0.500 |
| k |
0.800 |
| δ90 |
3.460 |
| 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 |
+4.9812 |
-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) |
| 2026-06-01 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 |
| 2026-06-02 12:00 |
23:53:55.27 |
-25:47:39.0 |
HIP 117796 |
10.00 |
| 2026-06-03 00:00 |
23:53:56.57 |
-25:48:19.7 |
HIP 117796 |
10.66 |
| 2026-06-03 12:00 |
23:53:57.82 |
-25:49:00.8 |
HIP 117796 |
11.32 |
| 2026-06-04 00:00 |
23:53:59.02 |
-25:49:42.3 |
HIP 117796 |
11.99 |
| 2026-06-04 12:00 |
23:54:00.16 |
-25:50:24.2 |
HIP 117796 |
12.67 |
| 2026-06-05 00:00 |
23:54:01.25 |
-25:51:06.5 |
HIP 117796 |
13.35 |
| 2026-06-05 12:00 |
23:54:02.30 |
-25:51:49.2 |
HIP 117796 |
14.03 |
| 2026-06-06 00:00 |
23:54:03.28 |
-25:52:32.2 |
HIP 117796 |
14.72 |
| 2026-06-06 12:00 |
23:54:04.22 |
-25:53:15.7 |
HIP 117796 |
15.41 |
| 2026-06-07 00:00 |
23:54:05.11 |
-25:53:59.5 |
HIP 117786 |
15.49 |
| 2026-06-07 12:00 |
23:54:05.94 |
-25:54:43.7 |
HIP 117786 |
15.20 |
| 2026-06-08 00:00 |
23:54:06.72 |
-25:55:28.3 |
HIP 117786 |
14.92 |
| 2026-06-08 12:00 |
23:54:07.45 |
-25:56:13.3 |
HIP 117786 |
14.67 |
| 2026-06-09 00:00 |
23:54:08.12 |
-25:56:58.6 |
HIP 117786 |
14.43 |
| 2026-06-09 12:00 |
23:54:08.75 |
-25:57:44.3 |
HIP 117786 |
14.22 |
| 2026-06-10 00:00 |
23:54:09.32 |
-25:58:30.4 |
HIP 117786 |
14.04 |
| 2026-06-10 12:00 |
23:54:09.83 |
-25:59:16.9 |
HIP 117786 |
13.89 |
| 2026-06-11 00:00 |
23:54:10.29 |
-26:00:03.7 |
HIP 117786 |
13.76 |
| 2026-06-11 12:00 |
23:54:10.70 |
-26:00:50.9 |
HIP 117786 |
13.67 |
| 2026-06-12 00:00 |
23:54:11.05 |
-26:01:38.4 |
HIP 117786 |
13.61 |
| 2026-06-12 12:00 |
23:54:11.35 |
-26:02:26.4 |
HIP 117786 |
13.58 |
| 2026-06-13 00:00 |
23:54:11.60 |
-26:03:14.6 |
HIP 117786 |
13.59 |
| 2026-06-13 12:00 |
23:54:11.79 |
-26:04:03.3 |
HIP 117786 |
13.63 |
| 2026-06-14 00:00 |
23:54:11.93 |
-26:04:52.3 |
HIP 117786 |
13.71 |
| 2026-06-14 12:00 |
23:54:12.01 |
-26:05:41.6 |
HIP 117786 |
13.83 |
| 2026-06-15 00:00 |
23:54:12.04 |
-26:06:31.3 |
HIP 117786 |
13.98 |
| 2026-06-15 12:00 |
23:54:12.01 |
-26:07:21.4 |
HIP 117786 |
14.17 |
| 2026-06-16 00:00 |
23:54:11.93 |
-26:08:11.8 |
HIP 117786 |
14.40 |
| 2026-06-16 12:00 |
23:54:11.79 |
-26:09:02.5 |
HIP 117786 |
14.66 |
| 2026-06-17 00:00 |
23:54:11.60 |
-26:09:53.6 |
HIP 117786 |
14.96 |
| 2026-06-17 12:00 |
23:54:11.35 |
-26:10:45.0 |
HIP 117786 |
15.28 |
| 2026-06-18 00:00 |
23:54:11.04 |
-26:11:36.7 |
HIP 117786 |
15.65 |
| 2026-06-18 12:00 |
23:54:10.68 |
-26:12:28.8 |
HIP 117786 |
16.04 |
| 2026-06-19 00:00 |
23:54:10.27 |
-26:13:21.2 |
HIP 117786 |
16.46 |
| 2026-06-19 12:00 |
23:54:09.80 |
-26:14:13.9 |
HIP 117786 |
16.91 |
| 2026-06-20 00:00 |
23:54:09.28 |
-26:15:07.0 |
HIP 117786 |
17.39 |
| 2026-06-20 12:00 |
23:54:08.70 |
-26:16:00.3 |
HIP 117786 |
17.90 |
| 2026-06-21 00:00 |
23:54:08.06 |
-26:16:54.0 |
HIP 117786 |
18.43 |
| 2026-06-21 12:00 |
23:54:07.37 |
-26:17:48.0 |
HIP 117786 |
18.98 |
| 2026-06-22 00:00 |
23:54:06.62 |
-26:18:42.3 |
HIP 117786 |
19.56 |