メタデータ
| 項目 |
値 |
| Designation |
C/2021 X2 (Bok) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2022-07-08T03:45:12.778560Z |
| Orbit solution date (soln_date, UTC) |
2024-04-15T15:43:28Z |
| Obs used |
95 |
| NEO |
- |
| M1 |
10.600 |
| K1 |
16.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-12-01T09:04:17.558400Z |
| Discovery magnitude (MPC) |
21.60 G |
| Discovery observatory (MPC) |
V00 · Kitt Peak-Bok |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2022-06-25.0000000 |
| e |
1.00130749 |
| q (au) |
2.994542 |
| a (au) |
-2290.292591 |
| i (deg) |
137.143974 |
| Ω (om, deg) |
228.798155 |
| ω (w, deg) |
193.283930 |
| M (ma, deg) |
-0.000118 |
等級
散乱 + 全体線形
$$
M_a = (10.258 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
10.258 |
| n |
6.000 |
| gf |
1.000 |
| 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) |
| 2026-05-12 00:00 |
18:10:34.75 |
-55:50:57.1 |
HIP 89214 |
18.39 |
| 2026-05-12 12:00 |
18:10:16.49 |
-55:51:38.4 |
HIP 88849 |
19.74 |
| 2026-05-13 00:00 |
18:09:58.10 |
-55:52:18.9 |
HIP 88849 |
17.97 |
| 2026-05-13 12:00 |
18:09:39.60 |
-55:52:58.7 |
HIP 88849 |
16.43 |
| 2026-05-14 00:00 |
18:09:20.97 |
-55:53:37.8 |
HIP 88849 |
15.19 |
| 2026-05-14 12:00 |
18:09:02.22 |
-55:54:16.2 |
HIP 88849 |
14.34 |
| 2026-05-15 00:00 |
18:08:43.36 |
-55:54:53.8 |
HIP 88849 |
13.96 |
| 2026-05-15 12:00 |
18:08:24.37 |
-55:55:30.7 |
HIP 88849 |
14.09 |
| 2026-05-16 00:00 |
18:08:05.27 |
-55:56:06.9 |
HIP 88849 |
14.72 |
| 2026-05-16 12:00 |
18:07:46.06 |
-55:56:42.3 |
HIP 88849 |
15.81 |
| 2026-05-17 00:00 |
18:07:26.73 |
-55:57:16.9 |
HIP 88849 |
17.27 |
| 2026-05-17 12:00 |
18:07:07.29 |
-55:57:50.8 |
HIP 88849 |
19.02 |
| 2026-05-18 00:00 |
18:06:47.75 |
-55:58:23.8 |
HIP 88849 |
20.99 |
| 2026-05-18 12:00 |
18:06:28.09 |
-55:58:56.1 |
HIP 88849 |
23.13 |
| 2026-05-19 00:00 |
18:06:08.34 |
-55:59:27.6 |
HIP 88849 |
25.41 |
| 2026-05-19 12:00 |
18:05:48.47 |
-55:59:58.3 |
HIP 88418 |
23.30 |
| 2026-05-20 00:00 |
18:05:28.51 |
-56:00:28.1 |
HIP 88418 |
20.51 |
| 2026-05-20 12:00 |
18:05:08.45 |
-56:00:57.2 |
HIP 88418 |
17.72 |
| 2026-05-21 00:00 |
18:04:48.28 |
-56:01:25.4 |
HIP 88418 |
14.94 |
| 2026-05-21 12:00 |
18:04:28.03 |
-56:01:52.8 |
HIP 88418 |
12.19 |
| 2026-05-22 00:00 |
18:04:07.67 |
-56:02:19.3 |
HIP 88418 |
9.51 |
| 2026-05-22 12:00 |
18:03:47.23 |
-56:02:45.0 |
HIP 88418 |
6.99 |
| 2026-05-23 00:00 |
18:03:26.69 |
-56:03:09.9 |
HIP 88418 |
4.89 |
| 2026-05-23 12:00 |
18:03:06.07 |
-56:03:33.9 |
HIP 88418 |
3.98 |
| 2026-05-24 00:00 |
18:02:45.36 |
-56:03:57.1 |
HIP 88418 |
4.99 |
| 2026-05-24 12:00 |
18:02:24.57 |
-56:04:19.3 |
HIP 88418 |
7.15 |
| 2026-05-25 00:00 |
18:02:03.69 |
-56:04:40.7 |
HIP 88262 |
8.15 |
| 2026-05-25 12:00 |
18:01:42.73 |
-56:05:01.3 |
HIP 88262 |
6.97 |
| 2026-05-26 00:00 |
18:01:21.69 |
-56:05:20.9 |
HIP 88262 |
6.93 |
| 2026-05-26 12:00 |
18:01:00.57 |
-56:05:39.7 |
HIP 88262 |
8.04 |
| 2026-05-27 00:00 |
18:00:39.38 |
-56:05:57.5 |
HIP 88262 |
9.94 |
| 2026-05-27 12:00 |
18:00:18.12 |
-56:06:14.5 |
HIP 88104 |
10.67 |
| 2026-05-28 00:00 |
17:59:56.78 |
-56:06:30.6 |
HIP 88104 |
9.20 |
| 2026-05-28 12:00 |
17:59:35.38 |
-56:06:45.7 |
HIP 88104 |
8.58 |
| 2026-05-29 00:00 |
17:59:13.91 |
-56:07:00.0 |
HIP 88104 |
8.98 |
| 2026-05-29 12:00 |
17:58:52.37 |
-56:07:13.3 |
HIP 88104 |
10.29 |
| 2026-05-30 00:00 |
17:58:30.76 |
-56:07:25.7 |
HIP 88104 |
12.24 |
| 2026-05-30 12:00 |
17:58:09.10 |
-56:07:37.2 |
HIP 88104 |
14.57 |
| 2026-05-31 00:00 |
17:57:47.38 |
-56:07:47.8 |
HIP 88104 |
17.13 |
| 2026-05-31 12:00 |
17:57:25.60 |
-56:07:57.4 |
HIP 87753 |
18.91 |
| 2026-06-01 00:00 |
17:57:03.76 |
-56:08:06.1 |
HIP 87753 |
16.32 |
| 2026-06-01 12:00 |
17:56:41.87 |
-56:08:13.8 |
HIP 87753 |
13.92 |
| 2026-06-02 00:00 |
17:56:19.92 |
-56:08:20.6 |
HIP 87753 |
11.82 |