メタデータ
| 項目 |
値 |
| Designation |
238P/Read |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2022-06-05T10:21:50.189760Z |
| Orbit solution date (soln_date, UTC) |
2024-05-30T15:51:09Z |
| Obs used |
119 |
| NEO |
- |
| M1 |
8.300 |
| K1 |
29.750 |
| PC |
0.030 |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2022-09-15.0000000 |
| e |
0.25167358 |
| q (au) |
2.369349 |
| a (au) |
3.166197 |
| i (deg) |
1.264088 |
| Ω (om, deg) |
51.625454 |
| ω (w, deg) |
324.206807 |
| M (ma, deg) |
17.768666 |
等級
散乱 + 全体線形
$$
M_a = (13.645 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
13.645 |
| n |
6.000 |
| gf |
0.980 |
| gb |
-0.872 |
| k |
1.000 |
| δ90 |
9.541 |
| 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 |
| 2021-06-11 |
2021-11-26 |
+2.0338 |
+0.530 |
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 |
16:08:11.28 |
-21:23:54.1 |
HIP 79020 |
6.25 |
| 2026-06-01 12:00 |
16:07:46.64 |
-21:22:55.8 |
HIP 79020 |
1.85 |
| 2026-06-02 00:00 |
16:07:22.05 |
-21:21:57.4 |
HIP 79020 |
5.94 |
| 2026-06-02 12:00 |
16:06:57.51 |
-21:20:58.8 |
HIP 79020 |
11.59 |
| 2026-06-03 00:00 |
16:06:33.03 |
-21:20:00.1 |
HIP 79020 |
17.33 |
| 2026-06-03 12:00 |
16:06:08.62 |
-21:19:01.3 |
HIP 79020 |
23.07 |
| 2026-06-04 00:00 |
16:05:44.27 |
-21:18:02.4 |
HIP 78872 |
26.23 |
| 2026-06-04 12:00 |
16:05:20.00 |
-21:17:03.4 |
HIP 78872 |
28.55 |
| 2026-06-05 00:00 |
16:04:55.81 |
-21:16:04.3 |
HIP 78872 |
31.74 |
| 2026-06-05 12:00 |
16:04:31.70 |
-21:15:05.2 |
HIP 78872 |
35.56 |
| 2026-06-06 00:00 |
16:04:07.68 |
-21:14:06.1 |
HIP 78872 |
39.81 |
| 2026-06-06 12:00 |
16:03:43.75 |
-21:13:06.9 |
HIP 78543 |
35.98 |
| 2026-06-07 00:00 |
16:03:19.93 |
-21:12:07.8 |
HIP 78467 |
31.38 |
| 2026-06-07 12:00 |
16:02:56.20 |
-21:11:08.6 |
HIP 78467 |
25.79 |
| 2026-06-08 00:00 |
16:02:32.59 |
-21:10:09.5 |
HIP 78467 |
20.24 |
| 2026-06-08 12:00 |
16:02:09.10 |
-21:09:10.5 |
HIP 78467 |
14.75 |
| 2026-06-09 00:00 |
16:01:45.72 |
-21:08:11.5 |
HIP 78467 |
9.37 |
| 2026-06-09 12:00 |
16:01:22.47 |
-21:07:12.6 |
HIP 78467 |
4.42 |
| 2026-06-10 00:00 |
16:00:59.34 |
-21:06:13.8 |
HIP 78467 |
3.46 |
| 2026-06-10 12:00 |
16:00:36.35 |
-21:05:15.2 |
HIP 78467 |
8.00 |
| 2026-06-11 00:00 |
16:00:13.50 |
-21:04:16.6 |
HIP 78467 |
13.21 |
| 2026-06-11 12:00 |
15:59:50.80 |
-21:03:18.3 |
HIP 78467 |
18.51 |
| 2026-06-12 00:00 |
15:59:28.25 |
-21:02:20.1 |
HIP 78467 |
23.82 |
| 2026-06-12 12:00 |
15:59:05.85 |
-21:01:22.1 |
HIP 78168 |
20.07 |
| 2026-06-13 00:00 |
15:58:43.60 |
-21:00:24.3 |
HIP 78168 |
14.80 |
| 2026-06-13 12:00 |
15:58:21.53 |
-20:59:26.7 |
HIP 78168 |
9.59 |
| 2026-06-14 00:00 |
15:57:59.62 |
-20:58:29.4 |
HIP 78168 |
4.50 |
| 2026-06-14 12:00 |
15:57:37.88 |
-20:57:32.3 |
HIP 78168 |
1.56 |
| 2026-06-15 00:00 |
15:57:16.33 |
-20:56:35.6 |
HIP 78168 |
6.12 |
| 2026-06-15 12:00 |
15:56:54.96 |
-20:55:39.1 |
HIP 78168 |
11.14 |
| 2026-06-16 00:00 |
15:56:33.77 |
-20:54:42.9 |
HIP 78168 |
16.15 |
| 2026-06-16 12:00 |
15:56:12.78 |
-20:53:47.1 |
HIP 77948 |
17.25 |
| 2026-06-17 00:00 |
15:55:51.98 |
-20:52:51.6 |
HIP 77948 |
12.42 |
| 2026-06-17 12:00 |
15:55:31.38 |
-20:51:56.5 |
HIP 77948 |
7.77 |
| 2026-06-18 00:00 |
15:55:10.99 |
-20:51:01.8 |
HIP 77948 |
3.85 |
| 2026-06-18 12:00 |
15:54:50.81 |
-20:50:07.5 |
HIP 77948 |
4.01 |
| 2026-06-19 00:00 |
15:54:30.84 |
-20:49:13.6 |
HIP 77948 |
7.92 |
| 2026-06-19 12:00 |
15:54:11.08 |
-20:48:20.2 |
HIP 77948 |
12.38 |
| 2026-06-20 00:00 |
15:53:51.55 |
-20:47:27.2 |
HIP 77948 |
16.92 |
| 2026-06-20 12:00 |
15:53:32.24 |
-20:46:34.6 |
HIP 77948 |
21.46 |
| 2026-06-21 00:00 |
15:53:13.15 |
-20:45:42.6 |
HIP 77948 |
25.96 |
| 2026-06-21 12:00 |
15:52:54.30 |
-20:44:51.0 |
HIP 77677 |
21.97 |
| 2026-06-22 00:00 |
15:52:35.68 |
-20:44:00.0 |
HIP 77677 |
17.72 |