メタデータ
| 項目 |
値 |
| Designation |
C/2021 K2 (MASTER) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-09-09T03:37:31.964160Z |
| Orbit solution date (soln_date, UTC) |
2022-07-16T01:42:47Z |
| Obs used |
80 |
| NEO |
- |
| M1 |
8.000 |
| K1 |
10.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-05-22T23:28:21.792000Z |
| Discovery magnitude (MPC) |
18.70 R |
| Discovery observatory (MPC) |
K95 · MASTER-SAAO Observatory, Sutherland |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2021-10-19.0000000 |
| e |
1.00120074 |
| q (au) |
5.467026 |
| a (au) |
-4553.055334 |
| i (deg) |
100.845478 |
| Ω (om, deg) |
282.245058 |
| ω (w, deg) |
343.321986 |
| M (ma, deg) |
0.000128 |
等級
散乱 + 全体線形
$$
M_a = (10.806 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
10.806 |
| n |
2.000 |
| gf |
0.998 |
| gb |
-1.000 |
| 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
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
16:30:57.52 |
+58:12:01.2 |
HIP 80689 |
19.61 |
| 2026-07-29 12:00 |
16:30:46.22 |
+58:10:39.5 |
HIP 80689 |
18.36 |
| 2026-07-30 00:00 |
16:30:35.06 |
+58:09:17.1 |
HIP 80689 |
17.28 |
| 2026-07-30 12:00 |
16:30:24.05 |
+58:07:54.1 |
HIP 80689 |
16.39 |
| 2026-07-31 00:00 |
16:30:13.18 |
+58:06:30.4 |
HIP 80689 |
15.73 |
| 2026-07-31 12:00 |
16:30:02.45 |
+58:05:06.2 |
HIP 80689 |
15.32 |
| 2026-08-01 00:00 |
16:29:51.86 |
+58:03:41.3 |
HIP 80689 |
15.19 |
| 2026-08-01 12:00 |
16:29:41.41 |
+58:02:15.8 |
HIP 80689 |
15.33 |
| 2026-08-02 00:00 |
16:29:31.11 |
+58:00:49.8 |
HIP 80689 |
15.74 |
| 2026-08-02 12:00 |
16:29:20.96 |
+57:59:23.2 |
HIP 80689 |
16.39 |
| 2026-08-03 00:00 |
16:29:10.94 |
+57:57:56.0 |
HIP 80689 |
17.27 |
| 2026-08-03 12:00 |
16:29:01.07 |
+57:56:28.3 |
HIP 80689 |
18.32 |
| 2026-08-04 00:00 |
16:28:51.35 |
+57:55:00.0 |
HIP 80689 |
19.53 |
| 2026-08-04 12:00 |
16:28:41.77 |
+57:53:31.2 |
HIP 80689 |
20.86 |
| 2026-08-05 00:00 |
16:28:32.34 |
+57:52:01.8 |
HIP 80689 |
22.29 |
| 2026-08-05 12:00 |
16:28:23.05 |
+57:50:32.0 |
HIP 80906 |
23.56 |
| 2026-08-06 00:00 |
16:28:13.91 |
+57:49:01.6 |
HIP 80906 |
24.82 |
| 2026-08-06 12:00 |
16:28:04.91 |
+57:47:30.7 |
HIP 80906 |
26.14 |
| 2026-08-07 00:00 |
16:27:56.06 |
+57:45:59.4 |
HIP 80906 |
27.52 |
| 2026-08-07 12:00 |
16:27:47.36 |
+57:44:27.6 |
HIP 80906 |
28.95 |
| 2026-08-08 00:00 |
16:27:38.80 |
+57:42:55.3 |
HIP 80906 |
30.42 |
| 2026-08-08 12:00 |
16:27:30.40 |
+57:41:22.5 |
HIP 80906 |
31.91 |
| 2026-08-09 00:00 |
16:27:22.13 |
+57:39:49.4 |
HIP 80775 |
31.73 |
| 2026-08-09 12:00 |
16:27:14.02 |
+57:38:15.8 |
HIP 80775 |
31.10 |
| 2026-08-10 00:00 |
16:27:06.05 |
+57:36:41.7 |
HIP 80775 |
30.55 |
| 2026-08-10 12:00 |
16:26:58.24 |
+57:35:07.3 |
HIP 80775 |
30.10 |
| 2026-08-11 00:00 |
16:26:50.56 |
+57:33:32.4 |
HIP 80775 |
29.74 |
| 2026-08-11 12:00 |
16:26:43.04 |
+57:31:57.2 |
HIP 80775 |
29.47 |
| 2026-08-12 00:00 |
16:26:35.67 |
+57:30:21.6 |
HIP 80775 |
29.31 |
| 2026-08-12 12:00 |
16:26:28.44 |
+57:28:45.6 |
HIP 80775 |
29.25 |
| 2026-08-13 00:00 |
16:26:21.36 |
+57:27:09.3 |
HIP 80775 |
29.29 |
| 2026-08-13 12:00 |
16:26:14.43 |
+57:25:32.6 |
HIP 80775 |
29.43 |
| 2026-08-14 00:00 |
16:26:07.65 |
+57:23:55.6 |
HIP 80775 |
29.67 |
| 2026-08-14 12:00 |
16:26:01.02 |
+57:22:18.3 |
HIP 80775 |
30.00 |
| 2026-08-15 00:00 |
16:25:54.53 |
+57:20:40.6 |
HIP 80775 |
30.42 |
| 2026-08-15 12:00 |
16:25:48.20 |
+57:19:02.7 |
HIP 80775 |
30.93 |
| 2026-08-16 00:00 |
16:25:42.01 |
+57:17:24.5 |
HIP 80775 |
31.51 |
| 2026-08-16 12:00 |
16:25:35.97 |
+57:15:46.0 |
HIP 80775 |
32.17 |
| 2026-08-17 00:00 |
16:25:30.07 |
+57:14:07.2 |
HIP 80775 |
32.91 |
| 2026-08-17 12:00 |
16:25:24.33 |
+57:12:28.2 |
HIP 80775 |
33.70 |
| 2026-08-18 00:00 |
16:25:18.73 |
+57:10:48.9 |
HIP 80775 |
34.56 |
| 2026-08-18 12:00 |
16:25:13.27 |
+57:09:09.4 |
HIP 80150 |
33.85 |
| 2026-08-19 00:00 |
16:25:07.97 |
+57:07:29.7 |
HIP 80150 |
32.44 |