メタデータ
| 項目 |
値 |
| Designation |
C/2021 P4 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2022-07-30T09:00:29.151360Z |
| Orbit solution date (soln_date, UTC) |
2024-07-30T14:57:24Z |
| Obs used |
954 |
| NEO |
- |
| M1 |
10.800 |
| K1 |
8.000 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2021-08-10T12:53:31.315200Z |
| Discovery magnitude (MPC) |
19.44 o |
| Discovery observatory (MPC) |
T05 · ATLAS-HKO, Haleakala |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2022-01-11.0000000 |
| e |
0.99656560 |
| q (au) |
1.080462 |
| a (au) |
314.600427 |
| i (deg) |
56.310801 |
| Ω (om, deg) |
348.094879 |
| ω (w, deg) |
175.822404 |
| M (ma, deg) |
359.964608 |
等級
散乱 + 全体線形
$$
M_a = (9.844 + 3.192\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
9.844 |
| n |
3.192 |
| gf |
0.800 |
| gb |
-0.500 |
| k |
1.000 |
| δ90 |
7.364 |
| 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 |
| 2021-08-10 |
2022-05-06 |
+2.3133 |
-1.380 |
| 2022-05-06 |
2022-06-13 |
-2.7477 |
+0.128 |
| 2022-06-13 |
2022-07-22 |
+21.5568 |
-2.643 |
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) |
| 2026-05-12 00:00 |
23:01:48.41 |
-39:33:58.0 |
HIP 113730 |
11.54 |
| 2026-05-12 12:00 |
23:01:52.82 |
-39:34:35.9 |
HIP 113730 |
10.81 |
| 2026-05-13 00:00 |
23:01:57.15 |
-39:35:14.3 |
HIP 113730 |
10.12 |
| 2026-05-13 12:00 |
23:02:01.40 |
-39:35:53.4 |
HIP 113730 |
9.48 |
| 2026-05-14 00:00 |
23:02:05.57 |
-39:36:33.1 |
HIP 113730 |
8.91 |
| 2026-05-14 12:00 |
23:02:09.65 |
-39:37:13.4 |
HIP 113730 |
8.42 |
| 2026-05-15 00:00 |
23:02:13.64 |
-39:37:54.3 |
HIP 113730 |
8.01 |
| 2026-05-15 12:00 |
23:02:17.55 |
-39:38:35.8 |
HIP 113730 |
7.71 |
| 2026-05-16 00:00 |
23:02:21.38 |
-39:39:17.9 |
HIP 113730 |
7.51 |
| 2026-05-16 12:00 |
23:02:25.12 |
-39:40:00.6 |
HIP 113795 |
7.05 |
| 2026-05-17 00:00 |
23:02:28.78 |
-39:40:43.9 |
HIP 113795 |
6.08 |
| 2026-05-17 12:00 |
23:02:32.35 |
-39:41:27.8 |
HIP 113795 |
5.12 |
| 2026-05-18 00:00 |
23:02:35.83 |
-39:42:12.3 |
HIP 113795 |
4.19 |
| 2026-05-18 12:00 |
23:02:39.22 |
-39:42:57.4 |
HIP 113795 |
3.29 |
| 2026-05-19 00:00 |
23:02:42.53 |
-39:43:43.0 |
HIP 113795 |
2.45 |
| 2026-05-19 12:00 |
23:02:45.75 |
-39:44:29.2 |
HIP 113795 |
1.76 |
| 2026-05-20 00:00 |
23:02:48.88 |
-39:45:16.0 |
HIP 113795 |
1.45 |
| 2026-05-20 12:00 |
23:02:51.93 |
-39:46:03.4 |
HIP 113795 |
1.72 |
| 2026-05-21 00:00 |
23:02:54.88 |
-39:46:51.3 |
HIP 113795 |
2.39 |
| 2026-05-21 12:00 |
23:02:57.75 |
-39:47:39.8 |
HIP 113795 |
3.21 |
| 2026-05-22 00:00 |
23:03:00.53 |
-39:48:28.9 |
HIP 113795 |
4.09 |
| 2026-05-22 12:00 |
23:03:03.22 |
-39:49:18.5 |
HIP 113795 |
5.00 |
| 2026-05-23 00:00 |
23:03:05.81 |
-39:50:08.6 |
HIP 113795 |
5.92 |
| 2026-05-23 12:00 |
23:03:08.32 |
-39:50:59.3 |
HIP 113795 |
6.85 |
| 2026-05-24 00:00 |
23:03:10.74 |
-39:51:50.5 |
HIP 113795 |
7.79 |
| 2026-05-24 12:00 |
23:03:13.07 |
-39:52:42.3 |
HIP 113795 |
8.73 |
| 2026-05-25 00:00 |
23:03:15.31 |
-39:53:34.6 |
HIP 113795 |
9.67 |
| 2026-05-25 12:00 |
23:03:17.46 |
-39:54:27.4 |
HIP 113795 |
10.61 |
| 2026-05-26 00:00 |
23:03:19.52 |
-39:55:20.7 |
HIP 113795 |
11.55 |
| 2026-05-26 12:00 |
23:03:21.49 |
-39:56:14.5 |
HIP 113795 |
12.50 |
| 2026-05-27 00:00 |
23:03:23.36 |
-39:57:08.9 |
HIP 113795 |
13.44 |
| 2026-05-27 12:00 |
23:03:25.15 |
-39:58:03.8 |
HIP 113795 |
14.39 |
| 2026-05-28 00:00 |
23:03:26.84 |
-39:58:59.1 |
HIP 113942 |
14.53 |
| 2026-05-28 12:00 |
23:03:28.44 |
-39:59:55.0 |
HIP 113942 |
13.73 |
| 2026-05-29 00:00 |
23:03:29.95 |
-40:00:51.4 |
HIP 113942 |
12.97 |
| 2026-05-29 12:00 |
23:03:31.37 |
-40:01:48.2 |
HIP 113942 |
12.24 |
| 2026-05-30 00:00 |
23:03:32.69 |
-40:02:45.6 |
HIP 113942 |
11.57 |
| 2026-05-30 12:00 |
23:03:33.92 |
-40:03:43.4 |
HIP 113942 |
10.96 |
| 2026-05-31 00:00 |
23:03:35.06 |
-40:04:41.7 |
HIP 113942 |
10.43 |
| 2026-05-31 12:00 |
23:03:36.11 |
-40:05:40.5 |
HIP 113942 |
9.98 |
| 2026-06-01 00:00 |
23:03:37.06 |
-40:06:39.7 |
HIP 113942 |
9.63 |
| 2026-06-01 12:00 |
23:03:37.92 |
-40:07:39.4 |
HIP 113942 |
9.39 |
| 2026-06-02 00:00 |
23:03:38.68 |
-40:08:39.6 |
HIP 113942 |
9.28 |