メタデータ
| 項目 |
値 |
| Designation |
C/2018 U1 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-11-02T19:19:13.019520Z |
| Orbit solution date (soln_date, UTC) |
2025-04-11T14:44:11Z |
| Obs used |
2459 |
| NEO |
- |
| M1 |
6.400 |
| K1 |
8.750 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2018-10-27T04:27:14.112000Z |
| Discovery magnitude (MPC) |
20.00 G |
| Discovery observatory (MPC) |
G96 · University of Arizona Mt. Lemmon Survey |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2020-09-11.0000000 |
| e |
1.00080698 |
| q (au) |
4.993873 |
| a (au) |
-6188.361643 |
| i (deg) |
108.301379 |
| Ω (om, deg) |
75.476939 |
| ω (w, deg) |
180.420486 |
| M (ma, deg) |
-0.000846 |
等級
散乱 + 全体線形
$$
M_a = (5.983 + 3.665\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
5.983 |
| n |
3.665 |
| gf |
0.858 |
| gb |
-0.500 |
| k |
0.942 |
| δ90 |
2.036 |
| 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 |
| 2018-10-27 |
2019-05-30 |
+10.1321 |
-9.496 |
| 2019-05-30 |
2021-10-08 |
-0.4295 |
+0.235 |
| 2022-02-03 |
2023-06-21 |
+3.8998 |
-2.549 |
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) |
| 2026-09-20 00:00 |
07:42:23.39 |
-44:53:33.5 |
HIP 37606 |
17.78 |
| 2026-09-20 12:00 |
07:42:26.64 |
-44:55:02.5 |
HIP 37606 |
16.19 |
| 2026-09-21 00:00 |
07:42:29.79 |
-44:56:31.8 |
HIP 37606 |
14.60 |
| 2026-09-21 12:00 |
07:42:32.86 |
-44:58:01.5 |
HIP 37606 |
13.01 |
| 2026-09-22 00:00 |
07:42:35.83 |
-44:59:31.6 |
HIP 37606 |
11.42 |
| 2026-09-22 12:00 |
07:42:38.70 |
-45:01:02.0 |
HIP 37606 |
9.83 |
| 2026-09-23 00:00 |
07:42:41.49 |
-45:02:32.8 |
HIP 37606 |
8.24 |
| 2026-09-23 12:00 |
07:42:44.18 |
-45:04:03.9 |
HIP 37606 |
6.65 |
| 2026-09-24 00:00 |
07:42:46.77 |
-45:05:35.4 |
HIP 37606 |
5.06 |
| 2026-09-24 12:00 |
07:42:49.27 |
-45:07:07.2 |
HIP 37606 |
3.48 |
| 2026-09-25 00:00 |
07:42:51.68 |
-45:08:39.3 |
HIP 37606 |
1.91 |
| 2026-09-25 12:00 |
07:42:53.99 |
-45:10:11.8 |
HIP 37606 |
0.57 |
| 2026-09-26 00:00 |
07:42:56.20 |
-45:11:44.5 |
HIP 37606 |
1.45 |
| 2026-09-26 12:00 |
07:42:58.32 |
-45:13:17.6 |
HIP 37606 |
2.99 |
| 2026-09-27 00:00 |
07:43:00.34 |
-45:14:51.0 |
HIP 37606 |
4.58 |
| 2026-09-27 12:00 |
07:43:02.26 |
-45:16:24.6 |
HIP 37606 |
6.17 |
| 2026-09-28 00:00 |
07:43:04.08 |
-45:17:58.6 |
HIP 37606 |
7.77 |
| 2026-09-28 12:00 |
07:43:05.81 |
-45:19:32.8 |
HIP 37606 |
9.36 |
| 2026-09-29 00:00 |
07:43:07.44 |
-45:21:07.2 |
HIP 37606 |
10.96 |
| 2026-09-29 12:00 |
07:43:08.97 |
-45:22:42.0 |
HIP 37606 |
12.57 |
| 2026-09-30 00:00 |
07:43:10.39 |
-45:24:17.0 |
HIP 37606 |
14.17 |
| 2026-09-30 12:00 |
07:43:11.72 |
-45:25:52.2 |
HIP 37606 |
15.77 |
| 2026-10-01 00:00 |
07:43:12.95 |
-45:27:27.7 |
HIP 37606 |
17.38 |
| 2026-10-01 12:00 |
07:43:14.08 |
-45:29:03.4 |
HIP 37606 |
18.98 |
| 2026-10-02 00:00 |
07:43:15.10 |
-45:30:39.3 |
HIP 37606 |
20.59 |
| 2026-10-02 12:00 |
07:43:16.03 |
-45:32:15.5 |
HIP 37649 |
19.82 |
| 2026-10-03 00:00 |
07:43:16.85 |
-45:33:51.8 |
HIP 37649 |
18.22 |
| 2026-10-03 12:00 |
07:43:17.56 |
-45:35:28.4 |
HIP 37649 |
16.61 |
| 2026-10-04 00:00 |
07:43:18.18 |
-45:37:05.1 |
HIP 37649 |
15.00 |
| 2026-10-04 12:00 |
07:43:18.69 |
-45:38:42.1 |
HIP 37649 |
13.40 |
| 2026-10-05 00:00 |
07:43:19.09 |
-45:40:19.2 |
HIP 37649 |
11.80 |
| 2026-10-05 12:00 |
07:43:19.39 |
-45:41:56.5 |
HIP 37649 |
10.21 |
| 2026-10-06 00:00 |
07:43:19.59 |
-45:43:33.9 |
HIP 37649 |
8.63 |
| 2026-10-06 12:00 |
07:43:19.68 |
-45:45:11.5 |
HIP 37649 |
7.08 |
| 2026-10-07 00:00 |
07:43:19.66 |
-45:46:49.2 |
HIP 37649 |
5.58 |
| 2026-10-07 12:00 |
07:43:19.54 |
-45:48:27.1 |
HIP 37649 |
4.19 |
| 2026-10-08 00:00 |
07:43:19.31 |
-45:50:05.0 |
HIP 37649 |
3.06 |
| 2026-10-08 12:00 |
07:43:18.97 |
-45:51:43.1 |
HIP 37649 |
2.57 |
| 2026-10-09 00:00 |
07:43:18.52 |
-45:53:21.3 |
HIP 37649 |
3.04 |
| 2026-10-09 12:00 |
07:43:17.97 |
-45:54:59.6 |
HIP 37649 |
4.17 |
| 2026-10-10 00:00 |
07:43:17.30 |
-45:56:37.9 |
HIP 37649 |
5.57 |
| 2026-10-10 12:00 |
07:43:16.53 |
-45:58:16.4 |
HIP 37649 |
7.09 |
| 2026-10-11 00:00 |
07:43:15.65 |
-45:59:54.9 |
HIP 37649 |
8.66 |