メタデータ
| 項目 |
値 |
| Designation |
C/2018 L2 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2018-12-02T13:55:55.485120Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:44Z |
| Obs used |
731 |
| NEO |
- |
| M1 |
9.500 |
| K1 |
10.750 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2018-06-06T07:58:35.040000Z |
| Discovery magnitude (MPC) |
15.60 o |
| Discovery observatory (MPC) |
T08 · ATLAS-MLO, Mauna Loa |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2018-12-29.0000000 |
| e |
0.99298130 |
| q (au) |
1.711711 |
| a (au) |
243.878556 |
| i (deg) |
67.423590 |
| Ω (om, deg) |
243.018259 |
| ω (w, deg) |
56.230818 |
| M (ma, deg) |
0.006837 |
等級
散乱 + 全体線形
$$
M_a = (8.836 + 4.978\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
8.836 |
| n |
4.978 |
| gf |
1.000 |
| gb |
-0.767 |
| k |
0.985 |
| 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
残差 (区間線形)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| 開始日 (UTC) |
終了日 (UTC) |
a |
b |
| 2018-06-04 |
2018-09-08 |
+4.1202 |
-1.557 |
| 2018-09-08 |
2018-12-01 |
+25.5943 |
-7.920 |
| 2018-12-03 |
2020-01-20 |
+2.8927 |
-2.045 |
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 |
04:48:50.30 |
+02:27:11.8 |
HIP 22319 |
16.70 |
| 2026-05-12 12:00 |
04:48:55.82 |
+02:27:25.0 |
HIP 22319 |
17.01 |
| 2026-05-13 00:00 |
04:49:01.36 |
+02:27:37.9 |
HIP 22319 |
17.44 |
| 2026-05-13 12:00 |
04:49:06.91 |
+02:27:50.7 |
HIP 22428 |
17.05 |
| 2026-05-14 00:00 |
04:49:12.47 |
+02:28:03.3 |
HIP 22428 |
16.77 |
| 2026-05-14 12:00 |
04:49:18.05 |
+02:28:15.6 |
HIP 22428 |
16.59 |
| 2026-05-15 00:00 |
04:49:23.65 |
+02:28:27.7 |
HIP 22428 |
16.53 |
| 2026-05-15 12:00 |
04:49:29.25 |
+02:28:39.7 |
HIP 22483 |
16.51 |
| 2026-05-16 00:00 |
04:49:34.87 |
+02:28:51.4 |
HIP 22483 |
15.76 |
| 2026-05-16 12:00 |
04:49:40.51 |
+02:29:02.9 |
HIP 22483 |
15.10 |
| 2026-05-17 00:00 |
04:49:46.16 |
+02:29:14.1 |
HIP 22483 |
14.55 |
| 2026-05-17 12:00 |
04:49:51.82 |
+02:29:25.2 |
HIP 22483 |
14.11 |
| 2026-05-18 00:00 |
04:49:57.49 |
+02:29:36.0 |
HIP 22483 |
13.81 |
| 2026-05-18 12:00 |
04:50:03.17 |
+02:29:46.6 |
HIP 22483 |
13.64 |
| 2026-05-19 00:00 |
04:50:08.86 |
+02:29:57.0 |
HIP 22483 |
13.62 |
| 2026-05-19 12:00 |
04:50:14.57 |
+02:30:07.2 |
HIP 22483 |
13.74 |
| 2026-05-20 00:00 |
04:50:20.28 |
+02:30:17.1 |
HIP 22483 |
14.01 |
| 2026-05-20 12:00 |
04:50:26.01 |
+02:30:26.9 |
HIP 22483 |
14.41 |
| 2026-05-21 00:00 |
04:50:31.74 |
+02:30:36.4 |
HIP 22483 |
14.94 |
| 2026-05-21 12:00 |
04:50:37.49 |
+02:30:45.6 |
HIP 22483 |
15.59 |
| 2026-05-22 00:00 |
04:50:43.24 |
+02:30:54.7 |
HIP 22483 |
16.33 |
| 2026-05-22 12:00 |
04:50:49.00 |
+02:31:03.5 |
HIP 22483 |
17.16 |
| 2026-05-23 00:00 |
04:50:54.77 |
+02:31:12.1 |
HIP 22483 |
18.07 |
| 2026-05-23 12:00 |
04:51:00.55 |
+02:31:20.4 |
HIP 22483 |
19.04 |
| 2026-05-24 00:00 |
04:51:06.34 |
+02:31:28.6 |
HIP 22483 |
20.06 |
| 2026-05-24 12:00 |
04:51:12.13 |
+02:31:36.5 |
HIP 22483 |
21.14 |
| 2026-05-25 00:00 |
04:51:17.93 |
+02:31:44.1 |
HIP 22483 |
22.26 |
| 2026-05-25 12:00 |
04:51:23.74 |
+02:31:51.6 |
HIP 22483 |
23.41 |
| 2026-05-26 00:00 |
04:51:29.55 |
+02:31:58.8 |
HIP 22483 |
24.60 |
| 2026-05-26 12:00 |
04:51:35.37 |
+02:32:05.8 |
HIP 22483 |
25.81 |
| 2026-05-27 00:00 |
04:51:41.19 |
+02:32:12.5 |
HIP 22730 |
25.42 |
| 2026-05-27 12:00 |
04:51:47.02 |
+02:32:19.0 |
HIP 22730 |
23.98 |
| 2026-05-28 00:00 |
04:51:52.85 |
+02:32:25.3 |
HIP 22730 |
22.54 |
| 2026-05-28 12:00 |
04:51:58.69 |
+02:32:31.3 |
HIP 22730 |
21.09 |
| 2026-05-29 00:00 |
04:52:04.53 |
+02:32:37.1 |
HIP 22730 |
19.65 |
| 2026-05-29 12:00 |
04:52:10.38 |
+02:32:42.7 |
HIP 22730 |
18.21 |
| 2026-05-30 00:00 |
04:52:16.23 |
+02:32:48.0 |
HIP 22730 |
16.77 |
| 2026-05-30 12:00 |
04:52:22.08 |
+02:32:53.1 |
HIP 22730 |
15.34 |
| 2026-05-31 00:00 |
04:52:27.94 |
+02:32:58.0 |
HIP 22730 |
13.91 |
| 2026-05-31 12:00 |
04:52:33.80 |
+02:33:02.6 |
HIP 22730 |
12.49 |
| 2026-06-01 00:00 |
04:52:39.66 |
+02:33:07.0 |
HIP 22730 |
11.08 |
| 2026-06-01 12:00 |
04:52:45.52 |
+02:33:11.1 |
HIP 22730 |
9.68 |
| 2026-06-02 00:00 |
04:52:51.39 |
+02:33:15.0 |
HIP 22730 |
8.30 |