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
$$
M_a = (9.803 + 3.189\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
9.803 |
| n |
3.189 |
| gf |
0.800 |
| gb |
-0.502 |
| 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 |
| 2021-08-10 |
2022-05-06 |
+2.3130 |
-1.380 |
| 2022-05-06 |
2022-06-13 |
-2.7466 |
+0.127 |
| 2022-06-13 |
2022-07-22 |
+21.5821 |
-2.646 |
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) |
| 2026-06-01 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 |
| 2026-06-02 12:00 |
23:03:39.35 |
-40:09:40.2 |
HIP 113942 |
9.29 |
| 2026-06-03 00:00 |
23:03:39.93 |
-40:10:41.3 |
HIP 113942 |
9.44 |
| 2026-06-03 12:00 |
23:03:40.41 |
-40:11:42.8 |
HIP 113942 |
9.71 |
| 2026-06-04 00:00 |
23:03:40.80 |
-40:12:44.8 |
HIP 113942 |
10.10 |
| 2026-06-04 12:00 |
23:03:41.10 |
-40:13:47.1 |
HIP 113942 |
10.60 |
| 2026-06-05 00:00 |
23:03:41.30 |
-40:14:50.0 |
HIP 113942 |
11.19 |
| 2026-06-05 12:00 |
23:03:41.40 |
-40:15:53.2 |
HIP 113942 |
11.86 |
| 2026-06-06 00:00 |
23:03:41.41 |
-40:16:56.9 |
HIP 113942 |
12.60 |
| 2026-06-06 12:00 |
23:03:41.32 |
-40:18:01.0 |
HIP 113942 |
13.40 |
| 2026-06-07 00:00 |
23:03:41.14 |
-40:19:05.5 |
HIP 113942 |
14.26 |
| 2026-06-07 12:00 |
23:03:40.86 |
-40:20:10.4 |
HIP 113942 |
15.15 |
| 2026-06-08 00:00 |
23:03:40.49 |
-40:21:15.7 |
HIP 113942 |
16.09 |
| 2026-06-08 12:00 |
23:03:40.02 |
-40:22:21.4 |
HIP 113942 |
17.06 |
| 2026-06-09 00:00 |
23:03:39.45 |
-40:23:27.5 |
HIP 113942 |
18.06 |
| 2026-06-09 12:00 |
23:03:38.79 |
-40:24:33.9 |
HIP 113942 |
19.09 |
| 2026-06-10 00:00 |
23:03:38.03 |
-40:25:40.8 |
HIP 113942 |
20.14 |
| 2026-06-10 12:00 |
23:03:37.18 |
-40:26:48.0 |
HIP 113942 |
21.21 |
| 2026-06-11 00:00 |
23:03:36.22 |
-40:27:55.6 |
HIP 113877 |
21.13 |
| 2026-06-11 12:00 |
23:03:35.17 |
-40:29:03.5 |
HIP 113877 |
20.01 |
| 2026-06-12 00:00 |
23:03:34.02 |
-40:30:11.8 |
HIP 113877 |
18.89 |
| 2026-06-12 12:00 |
23:03:32.78 |
-40:31:20.5 |
HIP 113877 |
17.78 |
| 2026-06-13 00:00 |
23:03:31.44 |
-40:32:29.5 |
HIP 113877 |
16.66 |
| 2026-06-13 12:00 |
23:03:30.00 |
-40:33:38.8 |
HIP 113877 |
15.56 |
| 2026-06-14 00:00 |
23:03:28.46 |
-40:34:48.5 |
HIP 113877 |
14.46 |
| 2026-06-14 12:00 |
23:03:26.82 |
-40:35:58.4 |
HIP 113877 |
13.38 |
| 2026-06-15 00:00 |
23:03:25.09 |
-40:37:08.7 |
HIP 113877 |
12.33 |
| 2026-06-15 12:00 |
23:03:23.26 |
-40:38:19.3 |
HIP 113877 |
11.30 |
| 2026-06-16 00:00 |
23:03:21.33 |
-40:39:30.2 |
HIP 113877 |
10.33 |
| 2026-06-16 12:00 |
23:03:19.30 |
-40:40:41.4 |
HIP 113877 |
9.42 |
| 2026-06-17 00:00 |
23:03:17.17 |
-40:41:52.9 |
HIP 113877 |
8.60 |
| 2026-06-17 12:00 |
23:03:14.95 |
-40:43:04.6 |
HIP 113877 |
7.91 |
| 2026-06-18 00:00 |
23:03:12.63 |
-40:44:16.7 |
HIP 113877 |
7.38 |
| 2026-06-18 12:00 |
23:03:10.21 |
-40:45:29.0 |
HIP 113877 |
7.06 |
| 2026-06-19 00:00 |
23:03:07.70 |
-40:46:41.5 |
HIP 113877 |
6.98 |
| 2026-06-19 12:00 |
23:03:05.08 |
-40:47:54.3 |
HIP 113877 |
7.16 |
| 2026-06-20 00:00 |
23:03:02.37 |
-40:49:07.3 |
HIP 113877 |
7.59 |
| 2026-06-20 12:00 |
23:02:59.57 |
-40:50:20.6 |
HIP 113877 |
8.23 |
| 2026-06-21 00:00 |
23:02:56.66 |
-40:51:34.1 |
HIP 113877 |
9.03 |
| 2026-06-21 12:00 |
23:02:53.66 |
-40:52:47.8 |
HIP 113877 |
9.98 |
| 2026-06-22 00:00 |
23:02:50.56 |
-40:54:01.7 |
HIP 113846 |
10.56 |