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) |
| 2026-07-29 00:00 |
07:29:53.31 |
-43:13:36.1 |
HIP 36377 |
8.48 |
| 2026-07-29 12:00 |
07:30:03.04 |
-43:13:51.9 |
HIP 36377 |
9.91 |
| 2026-07-30 00:00 |
07:30:12.74 |
-43:14:08.6 |
HIP 36377 |
11.43 |
| 2026-07-30 12:00 |
07:30:22.41 |
-43:14:26.2 |
HIP 36377 |
13.01 |
| 2026-07-31 00:00 |
07:30:32.05 |
-43:14:44.7 |
HIP 36611 |
13.39 |
| 2026-07-31 12:00 |
07:30:41.66 |
-43:15:04.1 |
HIP 36611 |
11.61 |
| 2026-08-01 00:00 |
07:30:51.24 |
-43:15:24.4 |
HIP 36611 |
9.83 |
| 2026-08-01 12:00 |
07:31:00.78 |
-43:15:45.6 |
HIP 36611 |
8.06 |
| 2026-08-02 00:00 |
07:31:10.30 |
-43:16:07.7 |
HIP 36611 |
6.29 |
| 2026-08-02 12:00 |
07:31:19.78 |
-43:16:30.6 |
HIP 36611 |
4.52 |
| 2026-08-03 00:00 |
07:31:29.22 |
-43:16:54.5 |
HIP 36611 |
2.76 |
| 2026-08-03 12:00 |
07:31:38.63 |
-43:17:19.2 |
HIP 36611 |
1.00 |
| 2026-08-04 00:00 |
07:31:48.00 |
-43:17:44.8 |
HIP 36611 |
0.79 |
| 2026-08-04 12:00 |
07:31:57.34 |
-43:18:11.2 |
HIP 36611 |
2.53 |
| 2026-08-05 00:00 |
07:32:06.65 |
-43:18:38.6 |
HIP 36611 |
4.28 |
| 2026-08-05 12:00 |
07:32:15.91 |
-43:19:06.8 |
HIP 36611 |
6.03 |
| 2026-08-06 00:00 |
07:32:25.14 |
-43:19:35.9 |
HIP 36611 |
7.78 |
| 2026-08-06 12:00 |
07:32:34.33 |
-43:20:05.8 |
HIP 36611 |
9.52 |
| 2026-08-07 00:00 |
07:32:43.48 |
-43:20:36.6 |
HIP 36611 |
11.26 |
| 2026-08-07 12:00 |
07:32:52.59 |
-43:21:08.3 |
HIP 36611 |
13.00 |
| 2026-08-08 00:00 |
07:33:01.66 |
-43:21:40.8 |
HIP 36611 |
14.74 |
| 2026-08-08 12:00 |
07:33:10.69 |
-43:22:14.2 |
HIP 36611 |
16.47 |
| 2026-08-09 00:00 |
07:33:19.68 |
-43:22:48.4 |
HIP 36775 |
16.92 |
| 2026-08-09 12:00 |
07:33:28.63 |
-43:23:23.4 |
HIP 36775 |
17.03 |
| 2026-08-10 00:00 |
07:33:37.53 |
-43:23:59.4 |
HIP 36775 |
17.32 |
| 2026-08-10 12:00 |
07:33:46.39 |
-43:24:36.1 |
HIP 36775 |
17.79 |
| 2026-08-11 00:00 |
07:33:55.21 |
-43:25:13.7 |
HIP 36775 |
18.43 |
| 2026-08-11 12:00 |
07:34:03.98 |
-43:25:52.1 |
HIP 36775 |
19.21 |
| 2026-08-12 00:00 |
07:34:12.70 |
-43:26:31.4 |
HIP 36775 |
20.12 |
| 2026-08-12 12:00 |
07:34:21.38 |
-43:27:11.5 |
HIP 36775 |
21.14 |
| 2026-08-13 00:00 |
07:34:30.01 |
-43:27:52.4 |
HIP 36775 |
22.26 |
| 2026-08-13 12:00 |
07:34:38.60 |
-43:28:34.1 |
HIP 36775 |
23.46 |
| 2026-08-14 00:00 |
07:34:47.13 |
-43:29:16.6 |
HIP 36775 |
24.72 |
| 2026-08-14 12:00 |
07:34:55.62 |
-43:30:00.0 |
HIP 36775 |
26.05 |
| 2026-08-15 00:00 |
07:35:04.06 |
-43:30:44.1 |
HIP 36775 |
27.42 |
| 2026-08-15 12:00 |
07:35:12.44 |
-43:31:29.0 |
HIP 36775 |
28.84 |
| 2026-08-16 00:00 |
07:35:20.78 |
-43:32:14.7 |
HIP 37148 |
29.74 |
| 2026-08-16 12:00 |
07:35:29.06 |
-43:33:01.3 |
HIP 37148 |
28.12 |
| 2026-08-17 00:00 |
07:35:37.30 |
-43:33:48.6 |
HIP 37148 |
26.50 |
| 2026-08-17 12:00 |
07:35:45.47 |
-43:34:36.6 |
HIP 37148 |
24.91 |
| 2026-08-18 00:00 |
07:35:53.60 |
-43:35:25.5 |
HIP 37148 |
23.33 |
| 2026-08-18 12:00 |
07:36:01.67 |
-43:36:15.1 |
HIP 37148 |
21.78 |
| 2026-08-19 00:00 |
07:36:09.69 |
-43:37:05.5 |
HIP 37148 |
20.26 |