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) |
| 2026-07-29 00:00 |
14:27:14.40 |
-08:03:55.1 |
HIP 70766 |
22.19 |
| 2026-07-29 12:00 |
14:27:10.65 |
-08:04:23.8 |
HIP 70766 |
23.20 |
| 2026-07-30 00:00 |
14:27:07.00 |
-08:04:52.9 |
HIP 70766 |
24.19 |
| 2026-07-30 12:00 |
14:27:03.45 |
-08:05:22.4 |
HIP 70766 |
25.18 |
| 2026-07-31 00:00 |
14:27:00.00 |
-08:05:52.2 |
HIP 70766 |
26.15 |
| 2026-07-31 12:00 |
14:26:56.65 |
-08:06:22.5 |
HIP 70766 |
27.11 |
| 2026-08-01 00:00 |
14:26:53.39 |
-08:06:53.1 |
HIP 70766 |
28.06 |
| 2026-08-01 12:00 |
14:26:50.23 |
-08:07:24.2 |
HIP 70766 |
28.99 |
| 2026-08-02 00:00 |
14:26:47.18 |
-08:07:55.6 |
HIP 70766 |
29.91 |
| 2026-08-02 12:00 |
14:26:44.21 |
-08:08:27.4 |
HIP 70766 |
30.81 |
| 2026-08-03 00:00 |
14:26:41.35 |
-08:08:59.6 |
HIP 70766 |
31.70 |
| 2026-08-03 12:00 |
14:26:38.58 |
-08:09:32.1 |
HIP 70766 |
32.57 |
| 2026-08-04 00:00 |
14:26:35.91 |
-08:10:05.0 |
HIP 70766 |
33.43 |
| 2026-08-04 12:00 |
14:26:33.34 |
-08:10:38.3 |
HIP 70766 |
34.27 |
| 2026-08-05 00:00 |
14:26:30.86 |
-08:11:12.0 |
HIP 70766 |
35.10 |
| 2026-08-05 12:00 |
14:26:28.48 |
-08:11:46.1 |
HIP 70766 |
35.92 |
| 2026-08-06 00:00 |
14:26:26.19 |
-08:12:20.5 |
HIP 70766 |
36.72 |
| 2026-08-06 12:00 |
14:26:24.00 |
-08:12:55.3 |
HIP 70766 |
37.51 |
| 2026-08-07 00:00 |
14:26:21.91 |
-08:13:30.4 |
HIP 70766 |
38.28 |
| 2026-08-07 12:00 |
14:26:19.91 |
-08:14:05.9 |
HIP 70766 |
39.04 |
| 2026-08-08 00:00 |
14:26:18.00 |
-08:14:41.8 |
HIP 70766 |
39.79 |
| 2026-08-08 12:00 |
14:26:16.19 |
-08:15:18.0 |
HIP 70766 |
40.52 |
| 2026-08-09 00:00 |
14:26:14.47 |
-08:15:54.5 |
HIP 70752 |
41.09 |
| 2026-08-09 12:00 |
14:26:12.85 |
-08:16:31.5 |
HIP 70752 |
40.93 |
| 2026-08-10 00:00 |
14:26:11.31 |
-08:17:08.7 |
HIP 70752 |
40.77 |
| 2026-08-10 12:00 |
14:26:09.88 |
-08:17:46.3 |
HIP 70752 |
40.59 |
| 2026-08-11 00:00 |
14:26:08.53 |
-08:18:24.3 |
HIP 70752 |
40.41 |
| 2026-08-11 12:00 |
14:26:07.28 |
-08:19:02.6 |
HIP 70752 |
40.22 |
| 2026-08-12 00:00 |
14:26:06.11 |
-08:19:41.2 |
HIP 70752 |
40.02 |
| 2026-08-12 12:00 |
14:26:05.04 |
-08:20:20.2 |
HIP 70752 |
39.81 |
| 2026-08-13 00:00 |
14:26:04.06 |
-08:20:59.5 |
HIP 70752 |
39.59 |
| 2026-08-13 12:00 |
14:26:03.17 |
-08:21:39.1 |
HIP 70752 |
39.36 |
| 2026-08-14 00:00 |
14:26:02.37 |
-08:22:19.1 |
HIP 70752 |
39.12 |
| 2026-08-14 12:00 |
14:26:01.66 |
-08:22:59.4 |
HIP 70752 |
38.87 |
| 2026-08-15 00:00 |
14:26:01.04 |
-08:23:40.0 |
HIP 70752 |
38.61 |
| 2026-08-15 12:00 |
14:26:00.51 |
-08:24:20.9 |
HIP 70752 |
38.34 |
| 2026-08-16 00:00 |
14:26:00.07 |
-08:25:02.1 |
HIP 70752 |
38.06 |
| 2026-08-16 12:00 |
14:25:59.71 |
-08:25:43.7 |
HIP 70752 |
37.77 |
| 2026-08-17 00:00 |
14:25:59.44 |
-08:26:25.5 |
HIP 70752 |
37.47 |
| 2026-08-17 12:00 |
14:25:59.26 |
-08:27:07.7 |
HIP 70752 |
37.16 |
| 2026-08-18 00:00 |
14:25:59.16 |
-08:27:50.1 |
HIP 70752 |
36.83 |
| 2026-08-18 12:00 |
14:25:59.15 |
-08:28:32.9 |
HIP 70752 |
36.50 |
| 2026-08-19 00:00 |
14:25:59.23 |
-08:29:15.9 |
HIP 70752 |
36.16 |