メタデータ
| 項目 |
値 |
| Designation |
C/2025 A1 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2027-03-12T16:07:18.552000Z |
| Orbit solution date (soln_date, UTC) |
2026-06-18T16:12:19Z |
| Obs used |
484 |
| NEO |
- |
| M1 |
5.500 |
| K1 |
12.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2025-01-02T06:39:55.180800Z |
| Discovery magnitude (MPC) |
20.50 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) |
2025-08-15.0000000 |
| e |
1.00250102 |
| q (au) |
5.345147 |
| a (au) |
-2137.190000 |
| i (deg) |
33.424560 |
| Ω (om, deg) |
101.331106 |
| ω (w, deg) |
68.048693 |
| M (ma, deg) |
-0.005733 |
等級
散乱 + 全体線形
$$
M_a = (4.576 + 4.828\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
4.576 |
| n |
4.828 |
| gf |
0.912 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
7.289 |
| 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 |
| 2021-11-11 |
2025-06-03 |
-4.6349 |
+4.324 |
| 2025-06-03 |
2026-06-09 |
+10.9163 |
-8.571 |
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 |
10:42:57.13 |
+31:04:15.5 |
HIP 52234 |
37.66 |
| 2026-09-20 12:00 |
10:43:29.40 |
+31:03:09.7 |
HIP 52638 |
37.80 |
| 2026-09-21 00:00 |
10:44:01.65 |
+31:02:04.5 |
HIP 52638 |
31.73 |
| 2026-09-21 12:00 |
10:44:33.87 |
+31:00:59.8 |
HIP 52638 |
26.13 |
| 2026-09-22 00:00 |
10:45:06.07 |
+30:59:55.7 |
HIP 52638 |
21.38 |
| 2026-09-22 12:00 |
10:45:38.25 |
+30:58:52.2 |
HIP 52638 |
18.16 |
| 2026-09-23 00:00 |
10:46:10.40 |
+30:57:49.2 |
HIP 52714 |
17.11 |
| 2026-09-23 12:00 |
10:46:42.53 |
+30:56:46.8 |
HIP 52687 |
16.73 |
| 2026-09-24 00:00 |
10:47:14.64 |
+30:55:45.0 |
HIP 52687 |
18.63 |
| 2026-09-24 12:00 |
10:47:46.72 |
+30:54:43.8 |
HIP 52687 |
22.63 |
| 2026-09-25 00:00 |
10:48:18.77 |
+30:53:43.1 |
HIP 52687 |
27.82 |
| 2026-09-25 12:00 |
10:48:50.81 |
+30:52:43.1 |
HIP 52687 |
33.66 |
| 2026-09-26 00:00 |
10:49:22.81 |
+30:51:43.7 |
HIP 52687 |
39.85 |
| 2026-09-26 12:00 |
10:49:54.79 |
+30:50:44.9 |
HIP 53112 |
41.07 |
| 2026-09-27 00:00 |
10:50:26.74 |
+30:49:46.7 |
HIP 53112 |
37.84 |
| 2026-09-27 12:00 |
10:50:58.66 |
+30:48:49.1 |
HIP 53193 |
34.93 |
| 2026-09-28 00:00 |
10:51:30.56 |
+30:47:52.2 |
HIP 53193 |
29.93 |
| 2026-09-28 12:00 |
10:52:02.42 |
+30:46:55.9 |
HIP 53193 |
25.84 |
| 2026-09-29 00:00 |
10:52:34.26 |
+30:46:00.3 |
HIP 53193 |
23.15 |
| 2026-09-29 12:00 |
10:53:06.07 |
+30:45:05.2 |
HIP 53324 |
21.57 |
| 2026-09-30 00:00 |
10:53:37.85 |
+30:44:10.9 |
HIP 53324 |
15.98 |
| 2026-09-30 12:00 |
10:54:09.60 |
+30:43:17.2 |
HIP 53324 |
11.87 |
| 2026-10-01 00:00 |
10:54:41.32 |
+30:42:24.2 |
HIP 53324 |
11.02 |
| 2026-10-01 12:00 |
10:55:13.00 |
+30:41:31.9 |
HIP 53324 |
14.03 |
| 2026-10-02 00:00 |
10:55:44.66 |
+30:40:40.2 |
HIP 53324 |
19.15 |
| 2026-10-02 12:00 |
10:56:16.28 |
+30:39:49.2 |
HIP 53571 |
17.13 |
| 2026-10-03 00:00 |
10:56:47.87 |
+30:38:59.0 |
HIP 53571 |
10.32 |
| 2026-10-03 12:00 |
10:57:19.43 |
+30:38:09.4 |
HIP 53571 |
3.67 |
| 2026-10-04 00:00 |
10:57:50.95 |
+30:37:20.6 |
HIP 53571 |
3.72 |
| 2026-10-04 12:00 |
10:58:22.44 |
+30:36:32.5 |
HIP 53636 |
7.06 |
| 2026-10-05 00:00 |
10:58:53.89 |
+30:35:45.1 |
HIP 53636 |
10.37 |
| 2026-10-05 12:00 |
10:59:25.31 |
+30:34:58.4 |
HIP 53636 |
16.05 |
| 2026-10-06 00:00 |
10:59:56.69 |
+30:34:12.5 |
HIP 53636 |
22.35 |
| 2026-10-06 12:00 |
11:00:28.04 |
+30:33:27.4 |
HIP 53969 |
26.61 |
| 2026-10-07 00:00 |
11:00:59.34 |
+30:32:43.0 |
HIP 53969 |
20.00 |
| 2026-10-07 12:00 |
11:01:30.61 |
+30:31:59.3 |
HIP 53969 |
13.59 |
| 2026-10-08 00:00 |
11:02:01.84 |
+30:31:16.5 |
HIP 53969 |
7.82 |
| 2026-10-08 12:00 |
11:02:33.02 |
+30:30:34.4 |
HIP 53969 |
5.43 |
| 2026-10-09 00:00 |
11:03:04.17 |
+30:29:53.2 |
HIP 54003 |
5.63 |
| 2026-10-09 12:00 |
11:03:35.28 |
+30:29:12.7 |
HIP 54028 |
7.74 |
| 2026-10-10 00:00 |
11:04:06.34 |
+30:28:33.0 |
HIP 54028 |
13.15 |
| 2026-10-10 12:00 |
11:04:37.36 |
+30:27:54.2 |
HIP 54230 |
16.61 |
| 2026-10-11 00:00 |
11:05:08.34 |
+30:27:16.2 |
HIP 54230 |
11.64 |