メタデータ
| 項目 |
値 |
| Designation |
C/2020 M5 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-08-19T21:12:41.952960Z |
| Orbit solution date (soln_date, UTC) |
2023-03-28T19:42:35Z |
| Obs used |
1605 |
| NEO |
- |
| M1 |
7.600 |
| K1 |
11.500 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2020-06-30T13:19:39.388800Z |
| Discovery magnitude (MPC) |
19.44 o |
| Discovery observatory (MPC) |
T08 · ATLAS-MLO, Mauna Loa |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2021-08-02.0000000 |
| e |
0.99994908 |
| q (au) |
3.004334 |
| a (au) |
59004.546918 |
| i (deg) |
93.222721 |
| Ω (om, deg) |
352.095028 |
| ω (w, deg) |
126.340033 |
| M (ma, deg) |
359.999999 |
等級
散乱 + 全体線形
$$
M_a = (8.967 + 5.727\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
8.967 |
| n |
5.727 |
| gf |
1.000 |
| gb |
-0.785 |
| 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 |
| 2019-08-10 |
2021-08-18 |
+1.0283 |
-0.456 |
| 2021-08-23 |
2022-02-06 |
-4.3432 |
+1.747 |
| 2022-02-06 |
2022-04-28 |
-5.1639 |
+2.582 |
| 2022-04-28 |
2023-02-27 |
-0.1853 |
-0.920 |
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) |
| 2026-03-26 00:00 |
07:58:47.93 |
-56:25:11.1 |
HIP 38836 |
16.43 |
| 2026-03-26 12:00 |
07:58:39.33 |
-56:23:18.4 |
HIP 38836 |
15.85 |
| 2026-03-27 00:00 |
07:58:30.88 |
-56:21:25.3 |
HIP 38836 |
15.60 |
| 2026-03-27 12:00 |
07:58:22.59 |
-56:19:31.9 |
HIP 38836 |
15.67 |
| 2026-03-28 00:00 |
07:58:14.44 |
-56:17:38.2 |
HIP 38836 |
16.07 |
| 2026-03-28 12:00 |
07:58:06.44 |
-56:15:44.2 |
HIP 38996 |
16.18 |
| 2026-03-29 00:00 |
07:57:58.60 |
-56:13:49.9 |
HIP 38996 |
14.95 |
| 2026-03-29 12:00 |
07:57:50.90 |
-56:11:55.3 |
HIP 38996 |
13.95 |
| 2026-03-30 00:00 |
07:57:43.35 |
-56:10:00.4 |
HIP 38996 |
13.22 |
| 2026-03-30 12:00 |
07:57:35.95 |
-56:08:05.3 |
HIP 38996 |
12.81 |
| 2026-03-31 00:00 |
07:57:28.69 |
-56:06:09.9 |
HIP 38996 |
12.74 |
| 2026-03-31 12:00 |
07:57:21.59 |
-56:04:14.2 |
HIP 38996 |
13.02 |
| 2026-04-01 00:00 |
07:57:14.63 |
-56:02:18.4 |
HIP 38996 |
13.62 |
| 2026-04-01 12:00 |
07:57:07.83 |
-56:00:22.3 |
HIP 38996 |
14.50 |
| 2026-04-02 00:00 |
07:57:01.17 |
-55:58:26.1 |
HIP 38996 |
15.62 |
| 2026-04-02 12:00 |
07:56:54.65 |
-55:56:29.6 |
HIP 38996 |
16.91 |
| 2026-04-03 00:00 |
07:56:48.29 |
-55:54:33.0 |
HIP 38996 |
18.35 |
| 2026-04-03 12:00 |
07:56:42.07 |
-55:52:36.2 |
HIP 38996 |
19.90 |
| 2026-04-04 00:00 |
07:56:36.00 |
-55:50:39.2 |
HIP 38996 |
21.54 |
| 2026-04-04 12:00 |
07:56:30.08 |
-55:48:42.1 |
HIP 38583 |
22.56 |
| 2026-04-05 00:00 |
07:56:24.30 |
-55:46:44.9 |
HIP 38583 |
21.13 |
| 2026-04-05 12:00 |
07:56:18.67 |
-55:44:47.5 |
HIP 38583 |
19.83 |
| 2026-04-06 00:00 |
07:56:13.19 |
-55:42:50.0 |
HIP 38583 |
18.70 |
| 2026-04-06 12:00 |
07:56:07.85 |
-55:40:52.4 |
HIP 38583 |
17.77 |
| 2026-04-07 00:00 |
07:56:02.66 |
-55:38:54.7 |
HIP 38583 |
17.07 |
| 2026-04-07 12:00 |
07:55:57.61 |
-55:36:57.0 |
HIP 38583 |
16.63 |
| 2026-04-08 00:00 |
07:55:52.71 |
-55:34:59.1 |
HIP 38583 |
16.45 |
| 2026-04-08 12:00 |
07:55:47.95 |
-55:33:01.3 |
HIP 38583 |
16.56 |
| 2026-04-09 00:00 |
07:55:43.34 |
-55:31:03.3 |
HIP 38583 |
16.94 |
| 2026-04-09 12:00 |
07:55:38.87 |
-55:29:05.3 |
HIP 38583 |
17.57 |
| 2026-04-10 00:00 |
07:55:34.55 |
-55:27:07.3 |
HIP 38583 |
18.43 |
| 2026-04-10 12:00 |
07:55:30.37 |
-55:25:09.3 |
HIP 38583 |
19.48 |
| 2026-04-11 00:00 |
07:55:26.33 |
-55:23:11.3 |
HIP 38583 |
20.70 |
| 2026-04-11 12:00 |
07:55:22.44 |
-55:21:13.3 |
HIP 38583 |
22.04 |
| 2026-04-12 00:00 |
07:55:18.69 |
-55:19:15.3 |
HIP 38583 |
23.50 |
| 2026-04-12 12:00 |
07:55:15.08 |
-55:17:17.4 |
HIP 38583 |
25.05 |
| 2026-04-13 00:00 |
07:55:11.61 |
-55:15:19.4 |
HIP 38583 |
26.66 |
| 2026-04-13 12:00 |
07:55:08.29 |
-55:13:21.6 |
HIP 38583 |
28.34 |
| 2026-04-14 00:00 |
07:55:05.10 |
-55:11:23.8 |
HIP 38583 |
30.06 |
| 2026-04-14 12:00 |
07:55:02.06 |
-55:09:26.0 |
HIP 38671 |
30.94 |
| 2026-04-15 00:00 |
07:54:59.16 |
-55:07:28.4 |
HIP 38671 |
28.99 |
| 2026-04-15 12:00 |
07:54:56.39 |
-55:05:30.8 |
HIP 38671 |
27.04 |
| 2026-04-16 00:00 |
07:54:53.77 |
-55:03:33.4 |
HIP 38671 |
25.11 |