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 · 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
$$
M_a = (5.982 + 3.665\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
5.982 |
| n |
3.665 |
| gf |
0.858 |
| gb |
-0.500 |
| k |
0.942 |
| δ90 |
2.042 |
| 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) |
| 2026-05-12 00:00 |
07:05:30.04 |
-45:50:31.2 |
HIP 34261 |
9.80 |
| 2026-05-12 12:00 |
07:05:36.30 |
-45:48:17.9 |
HIP 34261 |
11.07 |
| 2026-05-13 00:00 |
07:05:42.63 |
-45:46:05.3 |
HIP 34261 |
12.68 |
| 2026-05-13 12:00 |
07:05:49.05 |
-45:43:53.6 |
HIP 34261 |
14.52 |
| 2026-05-14 00:00 |
07:05:55.54 |
-45:41:42.7 |
HIP 34261 |
16.51 |
| 2026-05-14 12:00 |
07:06:02.11 |
-45:39:32.6 |
HIP 34261 |
18.59 |
| 2026-05-15 00:00 |
07:06:08.75 |
-45:37:23.3 |
HIP 34261 |
20.75 |
| 2026-05-15 12:00 |
07:06:15.47 |
-45:35:14.9 |
HIP 34261 |
22.95 |
| 2026-05-16 00:00 |
07:06:22.26 |
-45:33:07.3 |
HIP 34261 |
25.18 |
| 2026-05-16 12:00 |
07:06:29.13 |
-45:31:00.6 |
HIP 34261 |
27.43 |
| 2026-05-17 00:00 |
07:06:36.07 |
-45:28:54.7 |
HIP 34322 |
26.05 |
| 2026-05-17 12:00 |
07:06:43.07 |
-45:26:49.6 |
HIP 34322 |
23.85 |
| 2026-05-18 00:00 |
07:06:50.15 |
-45:24:45.4 |
HIP 34322 |
21.70 |
| 2026-05-18 12:00 |
07:06:57.30 |
-45:22:42.1 |
HIP 34322 |
19.63 |
| 2026-05-19 00:00 |
07:07:04.52 |
-45:20:39.7 |
HIP 34322 |
17.66 |
| 2026-05-19 12:00 |
07:07:11.81 |
-45:18:38.1 |
HIP 34322 |
15.83 |
| 2026-05-20 00:00 |
07:07:19.16 |
-45:16:37.4 |
HIP 34322 |
14.19 |
| 2026-05-20 12:00 |
07:07:26.58 |
-45:14:37.6 |
HIP 34322 |
12.80 |
| 2026-05-21 00:00 |
07:07:34.07 |
-45:12:38.7 |
HIP 34322 |
11.76 |
| 2026-05-21 12:00 |
07:07:41.62 |
-45:10:40.7 |
HIP 34322 |
11.17 |
| 2026-05-22 00:00 |
07:07:49.23 |
-45:08:43.5 |
HIP 34322 |
11.07 |
| 2026-05-22 12:00 |
07:07:56.91 |
-45:06:47.3 |
HIP 34322 |
11.50 |
| 2026-05-23 00:00 |
07:08:04.65 |
-45:04:51.9 |
HIP 34322 |
12.38 |
| 2026-05-23 12:00 |
07:08:12.45 |
-45:02:57.5 |
HIP 34322 |
13.63 |
| 2026-05-24 00:00 |
07:08:20.31 |
-45:01:03.9 |
HIP 34322 |
15.16 |
| 2026-05-24 12:00 |
07:08:28.23 |
-44:59:11.3 |
HIP 34322 |
16.88 |
| 2026-05-25 00:00 |
07:08:36.21 |
-44:57:19.6 |
HIP 34322 |
18.75 |
| 2026-05-25 12:00 |
07:08:44.25 |
-44:55:28.8 |
HIP 34322 |
20.71 |
| 2026-05-26 00:00 |
07:08:52.34 |
-44:53:38.9 |
HIP 34322 |
22.75 |
| 2026-05-26 12:00 |
07:09:00.49 |
-44:51:49.9 |
HIP 34675 |
22.34 |
| 2026-05-27 00:00 |
07:09:08.70 |
-44:50:01.9 |
HIP 34675 |
20.23 |
| 2026-05-27 12:00 |
07:09:16.96 |
-44:48:14.7 |
HIP 34675 |
18.16 |
| 2026-05-28 00:00 |
07:09:25.28 |
-44:46:28.5 |
HIP 34675 |
16.15 |
| 2026-05-28 12:00 |
07:09:33.65 |
-44:44:43.3 |
HIP 34675 |
14.23 |
| 2026-05-29 00:00 |
07:09:42.08 |
-44:42:58.9 |
HIP 34634 |
12.22 |
| 2026-05-29 12:00 |
07:09:50.55 |
-44:41:15.5 |
HIP 34634 |
9.93 |
| 2026-05-30 00:00 |
07:09:59.08 |
-44:39:33.0 |
HIP 34634 |
7.65 |
| 2026-05-30 12:00 |
07:10:07.66 |
-44:37:51.5 |
HIP 34634 |
5.37 |
| 2026-05-31 00:00 |
07:10:16.29 |
-44:36:10.9 |
HIP 34634 |
3.11 |
| 2026-05-31 12:00 |
07:10:24.97 |
-44:34:31.2 |
HIP 34634 |
0.90 |
| 2026-06-01 00:00 |
07:10:33.69 |
-44:32:52.5 |
HIP 34634 |
1.50 |
| 2026-06-01 12:00 |
07:10:42.47 |
-44:31:14.8 |
HIP 34634 |
3.73 |
| 2026-06-02 00:00 |
07:10:51.29 |
-44:29:37.9 |
HIP 34634 |
5.98 |