C/2018 A3 (ATLAS)
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) |
| 2026-02-03 00:00 |
23:35:17.53 |
-26:12:33.9 |
HIP 116269 |
24.88 |
| 2026-02-03 12:00 |
23:35:22.14 |
-26:11:54.2 |
HIP 116269 |
26.05 |
| 2026-02-04 00:00 |
23:35:26.78 |
-26:11:14.6 |
HIP 116269 |
27.23 |
| 2026-02-04 12:00 |
23:35:31.45 |
-26:10:35.1 |
HIP 116269 |
28.43 |
| 2026-02-05 00:00 |
23:35:36.15 |
-26:09:55.6 |
HIP 116547 |
27.75 |
| 2026-02-05 12:00 |
23:35:40.89 |
-26:09:16.3 |
HIP 116547 |
26.52 |
| 2026-02-06 00:00 |
23:35:45.65 |
-26:08:37.0 |
HIP 116547 |
25.28 |
| 2026-02-06 12:00 |
23:35:50.45 |
-26:07:57.9 |
HIP 116547 |
24.04 |
| 2026-02-07 00:00 |
23:35:55.27 |
-26:07:18.9 |
HIP 116547 |
22.81 |
| 2026-02-07 12:00 |
23:36:00.12 |
-26:06:40.0 |
HIP 116547 |
21.57 |
| 2026-02-08 00:00 |
23:36:05.01 |
-26:06:01.2 |
HIP 116547 |
20.33 |
| 2026-02-08 12:00 |
23:36:09.92 |
-26:05:22.5 |
HIP 116547 |
19.09 |
| 2026-02-09 00:00 |
23:36:14.86 |
-26:04:43.9 |
HIP 116547 |
17.85 |
| 2026-02-09 12:00 |
23:36:19.82 |
-26:04:05.4 |
HIP 116547 |
16.62 |
| 2026-02-10 00:00 |
23:36:24.82 |
-26:03:27.1 |
HIP 116547 |
15.39 |
| 2026-02-10 12:00 |
23:36:29.84 |
-26:02:48.9 |
HIP 116547 |
14.18 |
| 2026-02-11 00:00 |
23:36:34.89 |
-26:02:10.8 |
HIP 116547 |
12.97 |
| 2026-02-11 12:00 |
23:36:39.96 |
-26:01:32.9 |
HIP 116547 |
11.79 |
| 2026-02-12 00:00 |
23:36:45.06 |
-26:00:55.1 |
HIP 116547 |
10.63 |
| 2026-02-12 12:00 |
23:36:50.19 |
-26:00:17.4 |
HIP 116547 |
9.51 |
| 2026-02-13 00:00 |
23:36:55.34 |
-25:59:39.9 |
HIP 116547 |
8.45 |
| 2026-02-13 12:00 |
23:37:00.51 |
-25:59:02.5 |
HIP 116547 |
7.47 |
| 2026-02-14 00:00 |
23:37:05.71 |
-25:58:25.3 |
HIP 116547 |
6.61 |
| 2026-02-14 12:00 |
23:37:10.94 |
-25:57:48.2 |
HIP 116547 |
5.92 |
| 2026-02-15 00:00 |
23:37:16.18 |
-25:57:11.3 |
HIP 116547 |
5.48 |
| 2026-02-15 12:00 |
23:37:21.45 |
-25:56:34.6 |
HIP 116547 |
5.35 |
| 2026-02-16 00:00 |
23:37:26.74 |
-25:55:58.0 |
HIP 116547 |
5.55 |
| 2026-02-16 12:00 |
23:37:32.06 |
-25:55:21.6 |
HIP 116547 |
6.06 |
| 2026-02-17 00:00 |
23:37:37.39 |
-25:54:45.3 |
HIP 116547 |
6.80 |
| 2026-02-17 12:00 |
23:37:42.75 |
-25:54:09.2 |
HIP 116547 |
7.71 |
| 2026-02-18 00:00 |
23:37:48.13 |
-25:53:33.3 |
HIP 116547 |
8.74 |
| 2026-02-18 12:00 |
23:37:53.52 |
-25:52:57.6 |
HIP 116547 |
9.85 |
| 2026-02-19 00:00 |
23:37:58.94 |
-25:52:22.1 |
HIP 116547 |
11.02 |
| 2026-02-19 12:00 |
23:38:04.38 |
-25:51:46.7 |
HIP 116547 |
12.23 |
| 2026-02-20 00:00 |
23:38:09.84 |
-25:51:11.5 |
HIP 116547 |
13.48 |
| 2026-02-20 12:00 |
23:38:15.31 |
-25:50:36.6 |
HIP 116547 |
14.75 |
| 2026-02-21 00:00 |
23:38:20.80 |
-25:50:01.8 |
HIP 116547 |
16.04 |
| 2026-02-21 12:00 |
23:38:26.31 |
-25:49:27.2 |
HIP 116547 |
17.34 |
| 2026-02-22 00:00 |
23:38:31.84 |
-25:48:52.8 |
HIP 116547 |
18.66 |
| 2026-02-22 12:00 |
23:38:37.38 |
-25:48:18.6 |
HIP 116547 |
19.99 |
| 2026-02-23 00:00 |
23:38:42.95 |
-25:47:44.7 |
HIP 116547 |
21.32 |
| 2026-02-23 12:00 |
23:38:48.52 |
-25:47:10.9 |
HIP 116547 |
22.66 |
| 2026-02-24 00:00 |
23:38:54.11 |
-25:46:37.4 |
HIP 116547 |
24.01 |