メタデータ
| 項目 |
値 |
| Designation |
C/2019 S4 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2020-04-07T22:29:16.782720Z |
| Orbit solution date (soln_date, UTC) |
2021-09-20T00:12:43Z |
| Obs used |
267 |
| NEO |
- |
| M1 |
8.600 |
| K1 |
13.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2019-09-17T10:53:32.640000Z |
| Discovery magnitude (MPC) |
20.30 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) |
2020-02-18.0000000 |
| e |
0.98581834 |
| q (au) |
3.441733 |
| a (au) |
242.688906 |
| i (deg) |
92.025259 |
| Ω (om, deg) |
63.169569 |
| ω (w, deg) |
71.354510 |
| M (ma, deg) |
359.986982 |
等級
散乱 + 全体線形
$$
M_a = (6.827 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
6.827 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
1.000 |
| 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 |
| 2019-09-17 |
2020-04-01 |
+21.5169 |
-10.890 |
| 2020-05-29 |
2020-10-30 |
-14.1476 |
+7.524 |
| 2020-10-30 |
2021-09-12 |
+6.0879 |
-4.406 |
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) |
| 2026-06-01 00:00 |
15:41:36.18 |
-38:03:42.2 |
HIP 76890 |
10.66 |
| 2026-06-01 12:00 |
15:41:26.37 |
-38:03:27.9 |
HIP 76890 |
11.87 |
| 2026-06-02 00:00 |
15:41:16.59 |
-38:03:13.4 |
HIP 76890 |
13.26 |
| 2026-06-02 12:00 |
15:41:06.83 |
-38:02:58.6 |
HIP 76890 |
14.77 |
| 2026-06-03 00:00 |
15:40:57.10 |
-38:02:43.4 |
HIP 76890 |
16.37 |
| 2026-06-03 12:00 |
15:40:47.39 |
-38:02:28.0 |
HIP 76890 |
18.03 |
| 2026-06-04 00:00 |
15:40:37.71 |
-38:02:12.3 |
HIP 76890 |
19.74 |
| 2026-06-04 12:00 |
15:40:28.06 |
-38:01:56.3 |
HIP 76890 |
21.48 |
| 2026-06-05 00:00 |
15:40:18.44 |
-38:01:40.1 |
HIP 76890 |
23.25 |
| 2026-06-05 12:00 |
15:40:08.85 |
-38:01:23.5 |
HIP 76890 |
25.04 |
| 2026-06-06 00:00 |
15:39:59.29 |
-38:01:06.7 |
HIP 76890 |
26.84 |
| 2026-06-06 12:00 |
15:39:49.76 |
-38:00:49.6 |
HIP 76541 |
25.53 |
| 2026-06-07 00:00 |
15:39:40.26 |
-38:00:32.2 |
HIP 76541 |
24.06 |
| 2026-06-07 12:00 |
15:39:30.79 |
-38:00:14.6 |
HIP 76541 |
22.66 |
| 2026-06-08 00:00 |
15:39:21.36 |
-37:59:56.7 |
HIP 76541 |
21.34 |
| 2026-06-08 12:00 |
15:39:11.96 |
-37:59:38.6 |
HIP 76541 |
20.12 |
| 2026-06-09 00:00 |
15:39:02.60 |
-37:59:20.2 |
HIP 76541 |
19.01 |
| 2026-06-09 12:00 |
15:38:53.27 |
-37:59:01.5 |
HIP 76541 |
18.04 |
| 2026-06-10 00:00 |
15:38:43.98 |
-37:58:42.6 |
HIP 76541 |
17.22 |
| 2026-06-10 12:00 |
15:38:34.73 |
-37:58:23.5 |
HIP 76541 |
16.58 |
| 2026-06-11 00:00 |
15:38:25.51 |
-37:58:04.1 |
HIP 76541 |
16.12 |
| 2026-06-11 12:00 |
15:38:16.34 |
-37:57:44.4 |
HIP 76541 |
15.88 |
| 2026-06-12 00:00 |
15:38:07.20 |
-37:57:24.6 |
HIP 76541 |
15.85 |
| 2026-06-12 12:00 |
15:37:58.10 |
-37:57:04.5 |
HIP 76541 |
16.04 |
| 2026-06-13 00:00 |
15:37:49.04 |
-37:56:44.2 |
HIP 76541 |
16.43 |
| 2026-06-13 12:00 |
15:37:40.03 |
-37:56:23.6 |
HIP 76541 |
17.01 |
| 2026-06-14 00:00 |
15:37:31.06 |
-37:56:02.9 |
HIP 76457 |
16.54 |
| 2026-06-14 12:00 |
15:37:22.13 |
-37:55:41.9 |
HIP 76457 |
16.16 |
| 2026-06-15 00:00 |
15:37:13.24 |
-37:55:20.7 |
HIP 76457 |
15.98 |
| 2026-06-15 12:00 |
15:37:04.40 |
-37:54:59.4 |
HIP 76457 |
16.00 |
| 2026-06-16 00:00 |
15:36:55.61 |
-37:54:37.8 |
HIP 76457 |
16.22 |
| 2026-06-16 12:00 |
15:36:46.86 |
-37:54:16.0 |
HIP 76457 |
16.63 |
| 2026-06-17 00:00 |
15:36:38.16 |
-37:53:54.0 |
HIP 76457 |
17.21 |
| 2026-06-17 12:00 |
15:36:29.50 |
-37:53:31.9 |
HIP 76457 |
17.95 |
| 2026-06-18 00:00 |
15:36:20.90 |
-37:53:09.5 |
HIP 76457 |
18.82 |
| 2026-06-18 12:00 |
15:36:12.34 |
-37:52:47.0 |
HIP 76457 |
19.80 |
| 2026-06-19 00:00 |
15:36:03.83 |
-37:52:24.3 |
HIP 76457 |
20.87 |
| 2026-06-19 12:00 |
15:35:55.38 |
-37:52:01.4 |
HIP 76457 |
22.03 |
| 2026-06-20 00:00 |
15:35:46.97 |
-37:51:38.4 |
HIP 76457 |
23.25 |
| 2026-06-20 12:00 |
15:35:38.61 |
-37:51:15.1 |
HIP 76346 |
23.09 |
| 2026-06-21 00:00 |
15:35:30.31 |
-37:50:51.8 |
HIP 76346 |
22.76 |
| 2026-06-21 12:00 |
15:35:22.06 |
-37:50:28.3 |
HIP 76346 |
22.54 |
| 2026-06-22 00:00 |
15:35:13.86 |
-37:50:04.6 |
HIP 76346 |
22.44 |