メタデータ
| 項目 |
値 |
| Designation |
C/2020 S4 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2023-02-09T07:08:52.416960Z |
| Orbit solution date (soln_date, UTC) |
2024-07-07T00:42:12Z |
| Obs used |
1527 |
| NEO |
- |
| M1 |
10.700 |
| K1 |
6.250 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2020-09-16T12:33:54.979200Z |
| Discovery magnitude (MPC) |
21.30 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) |
2022-06-03.0000000 |
| e |
1.00061396 |
| q (au) |
3.369605 |
| a (au) |
-5488.353502 |
| i (deg) |
20.572607 |
| Ω (om, deg) |
117.721123 |
| ω (w, deg) |
21.002074 |
| M (ma, deg) |
-0.000609 |
等級
散乱 + 全体線形
$$
M_a = (12.434 + 2.232\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
12.434 |
| n |
2.232 |
| gf |
1.000 |
| gb |
-0.604 |
| 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 |
| 2020-09-16 |
2022-04-14 |
+4.3248 |
-3.352 |
| 2022-04-14 |
2023-02-09 |
-3.8591 |
+1.947 |
| 2023-02-09 |
2024-02-12 |
+14.5140 |
-7.785 |
| 2024-02-12 |
2024-06-05 |
-10.6982 |
+9.545 |
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 |
16:30:16.71 |
-05:41:15.0 |
HIP 80745 |
21.91 |
| 2026-07-29 12:00 |
16:30:13.44 |
-05:41:59.7 |
HIP 80745 |
21.80 |
| 2026-07-30 00:00 |
16:30:10.27 |
-05:42:44.7 |
HIP 80745 |
21.77 |
| 2026-07-30 12:00 |
16:30:07.18 |
-05:43:30.1 |
HIP 80745 |
21.81 |
| 2026-07-31 00:00 |
16:30:04.18 |
-05:44:15.7 |
HIP 80745 |
21.91 |
| 2026-07-31 12:00 |
16:30:01.27 |
-05:45:01.7 |
HIP 80834 |
21.54 |
| 2026-08-01 00:00 |
16:29:58.45 |
-05:45:47.9 |
HIP 80834 |
21.03 |
| 2026-08-01 12:00 |
16:29:55.72 |
-05:46:34.5 |
HIP 80834 |
20.56 |
| 2026-08-02 00:00 |
16:29:53.08 |
-05:47:21.3 |
HIP 80834 |
20.11 |
| 2026-08-02 12:00 |
16:29:50.52 |
-05:48:08.4 |
HIP 80834 |
19.69 |
| 2026-08-03 00:00 |
16:29:48.05 |
-05:48:55.9 |
HIP 80834 |
19.30 |
| 2026-08-03 12:00 |
16:29:45.68 |
-05:49:43.6 |
HIP 80834 |
18.93 |
| 2026-08-04 00:00 |
16:29:43.39 |
-05:50:31.6 |
HIP 80834 |
18.60 |
| 2026-08-04 12:00 |
16:29:41.19 |
-05:51:19.8 |
HIP 80834 |
18.29 |
| 2026-08-05 00:00 |
16:29:39.09 |
-05:52:08.4 |
HIP 80834 |
18.01 |
| 2026-08-05 12:00 |
16:29:37.07 |
-05:52:57.2 |
HIP 80834 |
17.77 |
| 2026-08-06 00:00 |
16:29:35.14 |
-05:53:46.3 |
HIP 80834 |
17.55 |
| 2026-08-06 12:00 |
16:29:33.31 |
-05:54:35.7 |
HIP 80834 |
17.35 |
| 2026-08-07 00:00 |
16:29:31.56 |
-05:55:25.3 |
HIP 80834 |
17.19 |
| 2026-08-07 12:00 |
16:29:29.90 |
-05:56:15.2 |
HIP 80834 |
17.06 |
| 2026-08-08 00:00 |
16:29:28.34 |
-05:57:05.4 |
HIP 80834 |
16.95 |
| 2026-08-08 12:00 |
16:29:26.87 |
-05:57:55.8 |
HIP 80834 |
16.88 |
| 2026-08-09 00:00 |
16:29:25.48 |
-05:58:46.4 |
HIP 80834 |
16.82 |
| 2026-08-09 12:00 |
16:29:24.19 |
-05:59:37.3 |
HIP 80834 |
16.80 |
| 2026-08-10 00:00 |
16:29:22.99 |
-06:00:28.5 |
HIP 80834 |
16.80 |
| 2026-08-10 12:00 |
16:29:21.89 |
-06:01:19.9 |
HIP 80834 |
16.83 |
| 2026-08-11 00:00 |
16:29:20.87 |
-06:02:11.5 |
HIP 80834 |
16.88 |
| 2026-08-11 12:00 |
16:29:19.94 |
-06:03:03.4 |
HIP 80834 |
16.96 |
| 2026-08-12 00:00 |
16:29:19.11 |
-06:03:55.5 |
HIP 80834 |
17.05 |
| 2026-08-12 12:00 |
16:29:18.37 |
-06:04:47.8 |
HIP 80834 |
17.18 |
| 2026-08-13 00:00 |
16:29:17.72 |
-06:05:40.4 |
HIP 80834 |
17.32 |
| 2026-08-13 12:00 |
16:29:17.17 |
-06:06:33.2 |
HIP 80834 |
17.49 |
| 2026-08-14 00:00 |
16:29:16.70 |
-06:07:26.2 |
HIP 80834 |
17.67 |
| 2026-08-14 12:00 |
16:29:16.33 |
-06:08:19.4 |
HIP 80834 |
17.88 |
| 2026-08-15 00:00 |
16:29:16.05 |
-06:09:12.8 |
HIP 80834 |
18.11 |
| 2026-08-15 12:00 |
16:29:15.86 |
-06:10:06.4 |
HIP 80834 |
18.35 |
| 2026-08-16 00:00 |
16:29:15.76 |
-06:11:00.2 |
HIP 80834 |
18.62 |
| 2026-08-16 12:00 |
16:29:15.76 |
-06:11:54.3 |
HIP 80834 |
18.90 |
| 2026-08-17 00:00 |
16:29:15.84 |
-06:12:48.5 |
HIP 80834 |
19.20 |
| 2026-08-17 12:00 |
16:29:16.02 |
-06:13:42.9 |
HIP 80834 |
19.52 |
| 2026-08-18 00:00 |
16:29:16.29 |
-06:14:37.5 |
HIP 80834 |
19.86 |
| 2026-08-18 12:00 |
16:29:16.65 |
-06:15:32.3 |
HIP 80834 |
20.22 |
| 2026-08-19 00:00 |
16:29:17.10 |
-06:16:27.2 |
HIP 80834 |
20.59 |