メタデータ
| 項目 |
値 |
| Designation |
C/2019 T2 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-04-22T06:32:53.350080Z |
| Orbit solution date (soln_date, UTC) |
2023-08-06T18:12:27Z |
| Obs used |
187 |
| NEO |
- |
| M1 |
12.700 |
| K1 |
5.750 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2019-10-09T03:16:41.376000Z |
| Discovery magnitude (MPC) |
20.60 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) |
2021-02-26.0000000 |
| e |
0.99872185 |
| q (au) |
2.645893 |
| a (au) |
2070.091183 |
| i (deg) |
111.488095 |
| Ω (om, deg) |
155.641811 |
| ω (w, deg) |
239.386315 |
| M (ma, deg) |
359.999422 |
等級
散乱 + 全体線形
$$
M_a = (11.950 + 3.858\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
11.950 |
| n |
3.858 |
| gf |
1.000 |
| gb |
-0.704 |
| k |
0.800 |
| 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 |
| 2019-08-26 |
2019-11-30 |
+22.3715 |
-17.071 |
| 2019-11-30 |
2020-07-16 |
-0.1476 |
-0.346 |
| 2020-07-16 |
2020-10-26 |
-4.8324 |
+2.665 |
| 2020-10-26 |
2021-04-11 |
-2.5155 |
+1.291 |
| 2021-05-22 |
2022-01-22 |
-5.7468 |
+3.701 |
| 2022-01-22 |
2023-06-14 |
+4.9021 |
-2.908 |
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 |
10:35:00.74 |
+18:22:53.0 |
HIP 51746 |
23.46 |
| 2026-09-20 12:00 |
10:35:07.42 |
+18:22:39.3 |
HIP 51900 |
22.53 |
| 2026-09-21 00:00 |
10:35:14.08 |
+18:22:25.8 |
HIP 51900 |
21.66 |
| 2026-09-21 12:00 |
10:35:20.72 |
+18:22:12.6 |
HIP 51900 |
20.88 |
| 2026-09-22 00:00 |
10:35:27.34 |
+18:21:59.6 |
HIP 51900 |
20.19 |
| 2026-09-22 12:00 |
10:35:33.93 |
+18:21:46.9 |
HIP 51900 |
19.60 |
| 2026-09-23 00:00 |
10:35:40.51 |
+18:21:34.4 |
HIP 51900 |
19.13 |
| 2026-09-23 12:00 |
10:35:47.06 |
+18:21:22.2 |
HIP 51874 |
18.73 |
| 2026-09-24 00:00 |
10:35:53.58 |
+18:21:10.3 |
HIP 51874 |
18.44 |
| 2026-09-24 12:00 |
10:36:00.08 |
+18:20:58.6 |
HIP 51874 |
18.27 |
| 2026-09-25 00:00 |
10:36:06.56 |
+18:20:47.2 |
HIP 51874 |
18.25 |
| 2026-09-25 12:00 |
10:36:13.02 |
+18:20:36.1 |
HIP 51874 |
18.36 |
| 2026-09-26 00:00 |
10:36:19.44 |
+18:20:25.3 |
HIP 52015 |
18.36 |
| 2026-09-26 12:00 |
10:36:25.85 |
+18:20:14.7 |
HIP 52015 |
16.85 |
| 2026-09-27 00:00 |
10:36:32.23 |
+18:20:04.4 |
HIP 52015 |
15.35 |
| 2026-09-27 12:00 |
10:36:38.58 |
+18:19:54.3 |
HIP 52015 |
13.85 |
| 2026-09-28 00:00 |
10:36:44.90 |
+18:19:44.6 |
HIP 52015 |
12.37 |
| 2026-09-28 12:00 |
10:36:51.20 |
+18:19:35.1 |
HIP 52015 |
10.91 |
| 2026-09-29 00:00 |
10:36:57.47 |
+18:19:25.9 |
HIP 52015 |
9.46 |
| 2026-09-29 12:00 |
10:37:03.72 |
+18:19:17.0 |
HIP 52015 |
8.03 |
| 2026-09-30 00:00 |
10:37:09.93 |
+18:19:08.4 |
HIP 52015 |
6.64 |
| 2026-09-30 12:00 |
10:37:16.12 |
+18:19:00.0 |
HIP 52015 |
5.29 |
| 2026-10-01 00:00 |
10:37:22.28 |
+18:18:52.0 |
HIP 52015 |
4.04 |
| 2026-10-01 12:00 |
10:37:28.41 |
+18:18:44.3 |
HIP 52015 |
3.00 |
| 2026-10-02 00:00 |
10:37:34.51 |
+18:18:36.8 |
HIP 52015 |
2.44 |
| 2026-10-02 12:00 |
10:37:40.58 |
+18:18:29.7 |
HIP 52015 |
2.65 |
| 2026-10-03 00:00 |
10:37:46.62 |
+18:18:22.8 |
HIP 52015 |
3.50 |
| 2026-10-03 12:00 |
10:37:52.63 |
+18:18:16.3 |
HIP 52015 |
4.64 |
| 2026-10-04 00:00 |
10:37:58.60 |
+18:18:10.1 |
HIP 52015 |
5.90 |
| 2026-10-04 12:00 |
10:38:04.55 |
+18:18:04.1 |
HIP 52015 |
7.21 |
| 2026-10-05 00:00 |
10:38:10.47 |
+18:17:58.5 |
HIP 52015 |
8.54 |
| 2026-10-05 12:00 |
10:38:16.35 |
+18:17:53.2 |
HIP 52015 |
9.89 |
| 2026-10-06 00:00 |
10:38:22.20 |
+18:17:48.3 |
HIP 52015 |
11.24 |
| 2026-10-06 12:00 |
10:38:28.01 |
+18:17:43.6 |
HIP 52015 |
12.59 |
| 2026-10-07 00:00 |
10:38:33.79 |
+18:17:39.3 |
HIP 52015 |
13.94 |
| 2026-10-07 12:00 |
10:38:39.54 |
+18:17:35.2 |
HIP 52015 |
15.28 |
| 2026-10-08 00:00 |
10:38:45.26 |
+18:17:31.5 |
HIP 52015 |
16.62 |
| 2026-10-08 12:00 |
10:38:50.93 |
+18:17:28.2 |
HIP 52015 |
17.95 |
| 2026-10-09 00:00 |
10:38:56.58 |
+18:17:25.1 |
HIP 52015 |
19.27 |
| 2026-10-09 12:00 |
10:39:02.18 |
+18:17:22.4 |
HIP 52207 |
19.13 |
| 2026-10-10 00:00 |
10:39:07.75 |
+18:17:20.1 |
HIP 52207 |
18.20 |
| 2026-10-10 12:00 |
10:39:13.29 |
+18:17:18.0 |
HIP 52207 |
17.32 |
| 2026-10-11 00:00 |
10:39:18.79 |
+18:17:16.4 |
HIP 52207 |
16.52 |