メタデータ
| 項目 |
値 |
| Designation |
C/2021 P2 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2023-01-22T16:20:24.480960Z |
| Orbit solution date (soln_date, UTC) |
2025-06-26T10:12:45Z |
| Obs used |
408 |
| NEO |
- |
| M1 |
7.500 |
| K1 |
11.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-08-07T12:35:04.617600Z |
| Discovery magnitude (MPC) |
21.50 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2023-02-01.0000000 |
| e |
0.99795112 |
| q (au) |
5.069092 |
| a (au) |
2474.083378 |
| i (deg) |
150.063521 |
| Ω (om, deg) |
32.079344 |
| ω (w, deg) |
76.687326 |
| M (ma, deg) |
0.000075 |
等級
散乱 + 全体線形
$$
M_a = (6.160 + 4.825\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
6.160 |
| n |
4.825 |
| gf |
1.000 |
| gb |
-0.500 |
| 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 |
| 2021-06-19 |
2022-11-22 |
+5.2167 |
-3.679 |
| 2023-04-26 |
2025-05-21 |
-4.7366 |
+3.148 |
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 |
14:28:38.94 |
-09:23:16.2 |
HIP 70784 |
37.02 |
| 2026-09-20 12:00 |
14:28:43.50 |
-09:24:12.4 |
HIP 70784 |
36.16 |
| 2026-09-21 00:00 |
14:28:48.10 |
-09:25:08.7 |
HIP 70784 |
35.33 |
| 2026-09-21 12:00 |
14:28:52.75 |
-09:26:05.1 |
HIP 70784 |
34.55 |
| 2026-09-22 00:00 |
14:28:57.46 |
-09:27:01.5 |
HIP 70784 |
33.82 |
| 2026-09-22 12:00 |
14:29:02.21 |
-09:27:58.1 |
HIP 70784 |
33.13 |
| 2026-09-23 00:00 |
14:29:07.01 |
-09:28:54.8 |
HIP 70784 |
32.51 |
| 2026-09-23 12:00 |
14:29:11.86 |
-09:29:51.5 |
HIP 70784 |
31.94 |
| 2026-09-24 00:00 |
14:29:16.76 |
-09:30:48.4 |
HIP 70784 |
31.45 |
| 2026-09-24 12:00 |
14:29:21.70 |
-09:31:45.3 |
HIP 70784 |
31.02 |
| 2026-09-25 00:00 |
14:29:26.69 |
-09:32:42.3 |
HIP 70784 |
30.67 |
| 2026-09-25 12:00 |
14:29:31.73 |
-09:33:39.4 |
HIP 70784 |
30.40 |
| 2026-09-26 00:00 |
14:29:36.81 |
-09:34:36.6 |
HIP 70784 |
30.21 |
| 2026-09-26 12:00 |
14:29:41.93 |
-09:35:33.8 |
HIP 70784 |
30.11 |
| 2026-09-27 00:00 |
14:29:47.10 |
-09:36:31.2 |
HIP 70784 |
30.10 |
| 2026-09-27 12:00 |
14:29:52.32 |
-09:37:28.5 |
HIP 70784 |
30.17 |
| 2026-09-28 00:00 |
14:29:57.58 |
-09:38:26.0 |
HIP 70784 |
30.34 |
| 2026-09-28 12:00 |
14:30:02.88 |
-09:39:23.5 |
HIP 70784 |
30.60 |
| 2026-09-29 00:00 |
14:30:08.22 |
-09:40:21.1 |
HIP 70784 |
30.95 |
| 2026-09-29 12:00 |
14:30:13.60 |
-09:41:18.8 |
HIP 70784 |
31.39 |
| 2026-09-30 00:00 |
14:30:19.03 |
-09:42:16.5 |
HIP 70784 |
31.91 |
| 2026-09-30 12:00 |
14:30:24.49 |
-09:43:14.2 |
HIP 71118 |
32.07 |
| 2026-10-01 00:00 |
14:30:30.00 |
-09:44:12.0 |
HIP 71118 |
30.66 |
| 2026-10-01 12:00 |
14:30:35.54 |
-09:45:09.9 |
HIP 71118 |
29.27 |
| 2026-10-02 00:00 |
14:30:41.13 |
-09:46:07.8 |
HIP 71118 |
27.91 |
| 2026-10-02 12:00 |
14:30:46.75 |
-09:47:05.7 |
HIP 71118 |
26.56 |
| 2026-10-03 00:00 |
14:30:52.41 |
-09:48:03.7 |
HIP 71118 |
25.25 |
| 2026-10-03 12:00 |
14:30:58.11 |
-09:49:01.8 |
HIP 71118 |
23.98 |
| 2026-10-04 00:00 |
14:31:03.85 |
-09:49:59.8 |
HIP 71118 |
22.76 |
| 2026-10-04 12:00 |
14:31:09.62 |
-09:50:57.9 |
HIP 71118 |
21.60 |
| 2026-10-05 00:00 |
14:31:15.43 |
-09:51:56.1 |
HIP 71118 |
20.51 |
| 2026-10-05 12:00 |
14:31:21.27 |
-09:52:54.2 |
HIP 71118 |
19.50 |
| 2026-10-06 00:00 |
14:31:27.15 |
-09:53:52.4 |
HIP 71118 |
18.59 |
| 2026-10-06 12:00 |
14:31:33.06 |
-09:54:50.6 |
HIP 71118 |
17.80 |
| 2026-10-07 00:00 |
14:31:39.00 |
-09:55:48.9 |
HIP 71118 |
17.14 |
| 2026-10-07 12:00 |
14:31:44.98 |
-09:56:47.1 |
HIP 71118 |
16.64 |
| 2026-10-08 00:00 |
14:31:50.99 |
-09:57:45.4 |
HIP 71118 |
16.32 |
| 2026-10-08 12:00 |
14:31:57.03 |
-09:58:43.6 |
HIP 71118 |
16.17 |
| 2026-10-09 00:00 |
14:32:03.11 |
-09:59:41.9 |
HIP 71118 |
16.22 |
| 2026-10-09 12:00 |
14:32:09.21 |
-10:00:40.2 |
HIP 71118 |
16.46 |
| 2026-10-10 00:00 |
14:32:15.34 |
-10:01:38.5 |
HIP 71118 |
16.88 |
| 2026-10-10 12:00 |
14:32:21.51 |
-10:02:36.7 |
HIP 71118 |
17.48 |
| 2026-10-11 00:00 |
14:32:27.70 |
-10:03:35.0 |
HIP 71188 |
18.08 |