メタデータ
| 項目 |
値 |
| Designation |
C/2020 X2 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2020-11-15T21:24:26.968320Z |
| Orbit solution date (soln_date, UTC) |
2024-01-04T23:42:39Z |
| Obs used |
253 |
| NEO |
- |
| M1 |
7.000 |
| K1 |
16.250 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2020-12-10T12:05:53.462400Z |
| Discovery magnitude (MPC) |
18.27 o |
| Discovery observatory (MPC) |
T08 · ATLAS-MLO, Mauna Loa |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2020-12-19.0000000 |
| e |
0.76624465 |
| q (au) |
3.828504 |
| a (au) |
16.378251 |
| i (deg) |
18.191452 |
| Ω (om, deg) |
105.458856 |
| ω (w, deg) |
347.357421 |
| M (ma, deg) |
0.492307 |
等級
散乱 + 全体線形
$$
M_a = (7.669 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
7.669 |
| n |
6.000 |
| gf |
0.990 |
| gb |
-0.845 |
| k |
0.998 |
| δ90 |
1.018 |
| 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 |
14:49:44.27 |
+02:34:41.6 |
HIP 72546 |
31.83 |
| 2026-05-12 12:00 |
14:49:36.51 |
+02:35:04.4 |
HIP 72546 |
32.42 |
| 2026-05-13 00:00 |
14:49:28.77 |
+02:35:26.6 |
HIP 72546 |
33.11 |
| 2026-05-13 12:00 |
14:49:21.04 |
+02:35:48.4 |
HIP 72312 |
31.81 |
| 2026-05-14 00:00 |
14:49:13.33 |
+02:36:09.7 |
HIP 72312 |
29.85 |
| 2026-05-14 12:00 |
14:49:05.63 |
+02:36:30.5 |
HIP 72312 |
27.90 |
| 2026-05-15 00:00 |
14:48:57.96 |
+02:36:50.8 |
HIP 72312 |
25.95 |
| 2026-05-15 12:00 |
14:48:50.30 |
+02:37:10.7 |
HIP 72312 |
24.01 |
| 2026-05-16 00:00 |
14:48:42.65 |
+02:37:30.0 |
HIP 72312 |
22.08 |
| 2026-05-16 12:00 |
14:48:35.03 |
+02:37:48.8 |
HIP 72312 |
20.15 |
| 2026-05-17 00:00 |
14:48:27.43 |
+02:38:07.2 |
HIP 72312 |
18.24 |
| 2026-05-17 12:00 |
14:48:19.86 |
+02:38:25.0 |
HIP 72312 |
16.32 |
| 2026-05-18 00:00 |
14:48:12.30 |
+02:38:42.3 |
HIP 72312 |
14.42 |
| 2026-05-18 12:00 |
14:48:04.77 |
+02:38:59.2 |
HIP 72312 |
12.53 |
| 2026-05-19 00:00 |
14:47:57.26 |
+02:39:15.5 |
HIP 72312 |
10.65 |
| 2026-05-19 12:00 |
14:47:49.78 |
+02:39:31.3 |
HIP 72312 |
8.79 |
| 2026-05-20 00:00 |
14:47:42.32 |
+02:39:46.6 |
HIP 72312 |
6.94 |
| 2026-05-20 12:00 |
14:47:34.89 |
+02:40:01.4 |
HIP 72312 |
5.14 |
| 2026-05-21 00:00 |
14:47:27.49 |
+02:40:15.6 |
HIP 72312 |
3.41 |
| 2026-05-21 12:00 |
14:47:20.11 |
+02:40:29.4 |
HIP 72312 |
1.97 |
| 2026-05-22 00:00 |
14:47:12.77 |
+02:40:42.6 |
HIP 72312 |
1.73 |
| 2026-05-22 12:00 |
14:47:05.45 |
+02:40:55.3 |
HIP 72312 |
2.99 |
| 2026-05-23 00:00 |
14:46:58.17 |
+02:41:07.5 |
HIP 72312 |
4.65 |
| 2026-05-23 12:00 |
14:46:50.91 |
+02:41:19.2 |
HIP 72312 |
6.39 |
| 2026-05-24 00:00 |
14:46:43.69 |
+02:41:30.4 |
HIP 72312 |
8.16 |
| 2026-05-24 12:00 |
14:46:36.50 |
+02:41:41.0 |
HIP 72312 |
9.94 |
| 2026-05-25 00:00 |
14:46:29.35 |
+02:41:51.1 |
HIP 72312 |
11.72 |
| 2026-05-25 12:00 |
14:46:22.23 |
+02:42:00.7 |
HIP 72312 |
13.50 |
| 2026-05-26 00:00 |
14:46:15.14 |
+02:42:09.8 |
HIP 72312 |
15.26 |
| 2026-05-26 12:00 |
14:46:08.09 |
+02:42:18.4 |
HIP 72312 |
17.03 |
| 2026-05-27 00:00 |
14:46:01.08 |
+02:42:26.4 |
HIP 72312 |
18.78 |
| 2026-05-27 12:00 |
14:45:54.10 |
+02:42:33.9 |
HIP 72312 |
20.52 |
| 2026-05-28 00:00 |
14:45:47.16 |
+02:42:40.9 |
HIP 72312 |
22.26 |
| 2026-05-28 12:00 |
14:45:40.26 |
+02:42:47.3 |
HIP 72312 |
23.98 |
| 2026-05-29 00:00 |
14:45:33.39 |
+02:42:53.3 |
HIP 72312 |
25.70 |
| 2026-05-29 12:00 |
14:45:26.57 |
+02:42:58.7 |
HIP 72312 |
27.41 |
| 2026-05-30 00:00 |
14:45:19.78 |
+02:43:03.5 |
HIP 72312 |
29.10 |
| 2026-05-30 12:00 |
14:45:13.04 |
+02:43:07.9 |
HIP 72312 |
30.79 |
| 2026-05-31 00:00 |
14:45:06.34 |
+02:43:11.7 |
HIP 72312 |
32.46 |
| 2026-05-31 12:00 |
14:44:59.68 |
+02:43:15.0 |
HIP 71948 |
31.07 |
| 2026-06-01 00:00 |
14:44:53.06 |
+02:43:17.8 |
HIP 71948 |
29.43 |
| 2026-06-01 12:00 |
14:44:46.48 |
+02:43:20.0 |
HIP 71948 |
27.80 |
| 2026-06-02 00:00 |
14:44:39.95 |
+02:43:21.7 |
HIP 71948 |
26.18 |