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) |
| 2026-07-29 00:00 |
15:28:04.86 |
-37:18:33.1 |
HIP 75727 |
3.40 |
| 2026-07-29 12:00 |
15:28:01.76 |
-37:18:09.3 |
HIP 75727 |
4.06 |
| 2026-07-30 00:00 |
15:27:58.74 |
-37:17:45.7 |
HIP 75727 |
4.73 |
| 2026-07-30 12:00 |
15:27:55.79 |
-37:17:22.2 |
HIP 75727 |
5.40 |
| 2026-07-31 00:00 |
15:27:52.92 |
-37:16:58.9 |
HIP 75727 |
6.07 |
| 2026-07-31 12:00 |
15:27:50.12 |
-37:16:35.7 |
HIP 75727 |
6.73 |
| 2026-08-01 00:00 |
15:27:47.40 |
-37:16:12.6 |
HIP 75727 |
7.38 |
| 2026-08-01 12:00 |
15:27:44.76 |
-37:15:49.7 |
HIP 75727 |
8.02 |
| 2026-08-02 00:00 |
15:27:42.19 |
-37:15:27.0 |
HIP 75727 |
8.65 |
| 2026-08-02 12:00 |
15:27:39.70 |
-37:15:04.4 |
HIP 75727 |
9.27 |
| 2026-08-03 00:00 |
15:27:37.28 |
-37:14:42.0 |
HIP 75727 |
9.88 |
| 2026-08-03 12:00 |
15:27:34.95 |
-37:14:19.7 |
HIP 75727 |
10.47 |
| 2026-08-04 00:00 |
15:27:32.68 |
-37:13:57.7 |
HIP 75727 |
11.05 |
| 2026-08-04 12:00 |
15:27:30.50 |
-37:13:35.7 |
HIP 75727 |
11.62 |
| 2026-08-05 00:00 |
15:27:28.39 |
-37:13:14.0 |
HIP 75727 |
12.17 |
| 2026-08-05 12:00 |
15:27:26.35 |
-37:12:52.4 |
HIP 75727 |
12.71 |
| 2026-08-06 00:00 |
15:27:24.40 |
-37:12:31.0 |
HIP 75727 |
13.24 |
| 2026-08-06 12:00 |
15:27:22.52 |
-37:12:09.8 |
HIP 75727 |
13.76 |
| 2026-08-07 00:00 |
15:27:20.71 |
-37:11:48.8 |
HIP 75727 |
14.26 |
| 2026-08-07 12:00 |
15:27:18.99 |
-37:11:27.9 |
HIP 75727 |
14.75 |
| 2026-08-08 00:00 |
15:27:17.34 |
-37:11:07.3 |
HIP 75727 |
15.22 |
| 2026-08-08 12:00 |
15:27:15.76 |
-37:10:46.8 |
HIP 75727 |
15.68 |
| 2026-08-09 00:00 |
15:27:14.26 |
-37:10:26.5 |
HIP 75727 |
16.13 |
| 2026-08-09 12:00 |
15:27:12.84 |
-37:10:06.5 |
HIP 75727 |
16.57 |
| 2026-08-10 00:00 |
15:27:11.50 |
-37:09:46.6 |
HIP 75727 |
16.99 |
| 2026-08-10 12:00 |
15:27:10.23 |
-37:09:26.9 |
HIP 75727 |
17.40 |
| 2026-08-11 00:00 |
15:27:09.04 |
-37:09:07.4 |
HIP 75727 |
17.80 |
| 2026-08-11 12:00 |
15:27:07.92 |
-37:08:48.2 |
HIP 75727 |
18.18 |
| 2026-08-12 00:00 |
15:27:06.88 |
-37:08:29.1 |
HIP 75727 |
18.55 |
| 2026-08-12 12:00 |
15:27:05.92 |
-37:08:10.3 |
HIP 75727 |
18.91 |
| 2026-08-13 00:00 |
15:27:05.03 |
-37:07:51.7 |
HIP 75727 |
19.25 |
| 2026-08-13 12:00 |
15:27:04.22 |
-37:07:33.3 |
HIP 75727 |
19.58 |
| 2026-08-14 00:00 |
15:27:03.48 |
-37:07:15.1 |
HIP 75727 |
19.90 |
| 2026-08-14 12:00 |
15:27:02.82 |
-37:06:57.1 |
HIP 75727 |
20.21 |
| 2026-08-15 00:00 |
15:27:02.24 |
-37:06:39.4 |
HIP 75727 |
20.50 |
| 2026-08-15 12:00 |
15:27:01.73 |
-37:06:21.9 |
HIP 75647 |
20.58 |
| 2026-08-16 00:00 |
15:27:01.30 |
-37:06:04.6 |
HIP 75647 |
20.31 |
| 2026-08-16 12:00 |
15:27:00.94 |
-37:05:47.6 |
HIP 75647 |
20.04 |
| 2026-08-17 00:00 |
15:27:00.66 |
-37:05:30.8 |
HIP 75647 |
19.77 |
| 2026-08-17 12:00 |
15:27:00.45 |
-37:05:14.2 |
HIP 75647 |
19.51 |
| 2026-08-18 00:00 |
15:27:00.32 |
-37:04:57.9 |
HIP 75647 |
19.25 |
| 2026-08-18 12:00 |
15:27:00.26 |
-37:04:41.8 |
HIP 75647 |
18.99 |
| 2026-08-19 00:00 |
15:27:00.27 |
-37:04:25.9 |
HIP 75647 |
18.73 |