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) |
| 2026-09-20 00:00 |
16:32:47.64 |
-07:18:44.6 |
HIP 81049 |
22.67 |
| 2026-09-20 12:00 |
16:32:53.59 |
-07:19:44.1 |
HIP 81049 |
23.28 |
| 2026-09-21 00:00 |
16:32:59.62 |
-07:20:43.5 |
HIP 81049 |
23.99 |
| 2026-09-21 12:00 |
16:33:05.73 |
-07:21:42.9 |
HIP 81049 |
24.82 |
| 2026-09-22 00:00 |
16:33:11.91 |
-07:22:42.3 |
HIP 81049 |
25.74 |
| 2026-09-22 12:00 |
16:33:18.16 |
-07:23:41.6 |
HIP 81049 |
26.75 |
| 2026-09-23 00:00 |
16:33:24.49 |
-07:24:40.9 |
HIP 81049 |
27.86 |
| 2026-09-23 12:00 |
16:33:30.89 |
-07:25:40.1 |
HIP 81049 |
29.04 |
| 2026-09-24 00:00 |
16:33:37.36 |
-07:26:39.3 |
HIP 81049 |
30.29 |
| 2026-09-24 12:00 |
16:33:43.90 |
-07:27:38.4 |
HIP 81049 |
31.61 |
| 2026-09-25 00:00 |
16:33:50.52 |
-07:28:37.5 |
HIP 81049 |
32.99 |
| 2026-09-25 12:00 |
16:33:57.20 |
-07:29:36.5 |
HIP 81049 |
34.42 |
| 2026-09-26 00:00 |
16:34:03.96 |
-07:30:35.4 |
HIP 81049 |
35.91 |
| 2026-09-26 12:00 |
16:34:10.79 |
-07:31:34.2 |
HIP 81049 |
37.44 |
| 2026-09-27 00:00 |
16:34:17.68 |
-07:32:33.0 |
HIP 81159 |
36.62 |
| 2026-09-27 12:00 |
16:34:24.65 |
-07:33:31.7 |
HIP 81159 |
35.50 |
| 2026-09-28 00:00 |
16:34:31.68 |
-07:34:30.4 |
HIP 81159 |
34.46 |
| 2026-09-28 12:00 |
16:34:38.79 |
-07:35:28.9 |
HIP 81159 |
33.50 |
| 2026-09-29 00:00 |
16:34:45.96 |
-07:36:27.4 |
HIP 81355 |
32.53 |
| 2026-09-29 12:00 |
16:34:53.20 |
-07:37:25.8 |
HIP 81355 |
30.53 |
| 2026-09-30 00:00 |
16:35:00.51 |
-07:38:24.1 |
HIP 81355 |
28.53 |
| 2026-09-30 12:00 |
16:35:07.88 |
-07:39:22.3 |
HIP 81355 |
26.52 |
| 2026-10-01 00:00 |
16:35:15.32 |
-07:40:20.4 |
HIP 81355 |
24.50 |
| 2026-10-01 12:00 |
16:35:22.83 |
-07:41:18.5 |
HIP 81355 |
22.48 |
| 2026-10-02 00:00 |
16:35:30.41 |
-07:42:16.4 |
HIP 81355 |
20.46 |
| 2026-10-02 12:00 |
16:35:38.05 |
-07:43:14.3 |
HIP 81355 |
18.44 |
| 2026-10-03 00:00 |
16:35:45.75 |
-07:44:12.0 |
HIP 81355 |
16.43 |
| 2026-10-03 12:00 |
16:35:53.52 |
-07:45:09.6 |
HIP 81355 |
14.45 |
| 2026-10-04 00:00 |
16:36:01.36 |
-07:46:07.1 |
HIP 81355 |
12.50 |
| 2026-10-04 12:00 |
16:36:09.26 |
-07:47:04.6 |
HIP 81355 |
10.62 |
| 2026-10-05 00:00 |
16:36:17.22 |
-07:48:01.9 |
HIP 81355 |
8.87 |
| 2026-10-05 12:00 |
16:36:25.25 |
-07:48:59.1 |
HIP 81355 |
7.34 |
| 2026-10-06 00:00 |
16:36:33.34 |
-07:49:56.1 |
HIP 81355 |
6.21 |
| 2026-10-06 12:00 |
16:36:41.49 |
-07:50:53.1 |
HIP 81355 |
5.75 |
| 2026-10-07 00:00 |
16:36:49.70 |
-07:51:49.9 |
HIP 81355 |
6.12 |
| 2026-10-07 12:00 |
16:36:57.98 |
-07:52:46.6 |
HIP 81355 |
7.21 |
| 2026-10-08 00:00 |
16:37:06.32 |
-07:53:43.2 |
HIP 81355 |
8.76 |
| 2026-10-08 12:00 |
16:37:14.71 |
-07:54:39.6 |
HIP 81355 |
10.58 |
| 2026-10-09 00:00 |
16:37:23.17 |
-07:55:35.9 |
HIP 81355 |
12.56 |
| 2026-10-09 12:00 |
16:37:31.69 |
-07:56:32.1 |
HIP 81355 |
14.64 |
| 2026-10-10 00:00 |
16:37:40.27 |
-07:57:28.1 |
HIP 81355 |
16.79 |
| 2026-10-10 12:00 |
16:37:48.91 |
-07:58:24.0 |
HIP 81355 |
18.99 |
| 2026-10-11 00:00 |
16:37:57.60 |
-07:59:19.7 |
HIP 81355 |
21.22 |