メタデータ
| 項目 |
値 |
| Designation |
C/2020 R4 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-03-01T22:27:03.700800Z |
| Orbit solution date (soln_date, UTC) |
2022-06-06T17:33:25Z |
| Obs used |
2399 |
| NEO |
- |
| M1 |
12.800 |
| K1 |
11.750 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2020-09-12T11:53:38.889600Z |
| Discovery magnitude (MPC) |
19.71 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) |
2021-03-13.0000000 |
| e |
0.98936453 |
| q (au) |
1.028587 |
| a (au) |
96.712911 |
| i (deg) |
164.463346 |
| Ω (om, deg) |
323.272439 |
| ω (w, deg) |
46.707930 |
| M (ma, deg) |
0.011466 |
等級
散乱 + 全体線形
$$
M_a = (12.395 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
12.395 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.526 |
| 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 |
| 2020-08-29 |
2020-11-08 |
-9.0126 |
+3.872 |
| 2020-11-08 |
2020-12-10 |
+15.0380 |
-3.885 |
| 2020-12-10 |
2021-02-27 |
+6.3925 |
-2.570 |
| 2021-03-04 |
2021-04-25 |
+19.4111 |
-2.321 |
| 2021-04-25 |
2021-06-04 |
+1.2854 |
-0.645 |
| 2021-06-04 |
2022-03-01 |
-6.4189 |
+0.769 |
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) |
| 2026-05-12 00:00 |
08:13:50.77 |
+15:04:46.3 |
HIP 40420 |
18.80 |
| 2026-05-12 12:00 |
08:13:52.66 |
+15:04:46.2 |
HIP 40420 |
18.35 |
| 2026-05-13 00:00 |
08:13:54.61 |
+15:04:45.9 |
HIP 40420 |
17.88 |
| 2026-05-13 12:00 |
08:13:56.61 |
+15:04:45.4 |
HIP 40420 |
17.40 |
| 2026-05-14 00:00 |
08:13:58.68 |
+15:04:44.6 |
HIP 40420 |
16.90 |
| 2026-05-14 12:00 |
08:14:00.80 |
+15:04:43.7 |
HIP 40420 |
16.39 |
| 2026-05-15 00:00 |
08:14:02.97 |
+15:04:42.5 |
HIP 40420 |
15.87 |
| 2026-05-15 12:00 |
08:14:05.20 |
+15:04:41.1 |
HIP 40420 |
15.34 |
| 2026-05-16 00:00 |
08:14:07.49 |
+15:04:39.5 |
HIP 40420 |
14.79 |
| 2026-05-16 12:00 |
08:14:09.83 |
+15:04:37.6 |
HIP 40420 |
14.22 |
| 2026-05-17 00:00 |
08:14:12.22 |
+15:04:35.5 |
HIP 40420 |
13.65 |
| 2026-05-17 12:00 |
08:14:14.67 |
+15:04:33.3 |
HIP 40420 |
13.06 |
| 2026-05-18 00:00 |
08:14:17.18 |
+15:04:30.7 |
HIP 40420 |
12.45 |
| 2026-05-18 12:00 |
08:14:19.73 |
+15:04:28.0 |
HIP 40420 |
11.84 |
| 2026-05-19 00:00 |
08:14:22.34 |
+15:04:25.1 |
HIP 40420 |
11.21 |
| 2026-05-19 12:00 |
08:14:25.01 |
+15:04:21.9 |
HIP 40420 |
10.57 |
| 2026-05-20 00:00 |
08:14:27.72 |
+15:04:18.6 |
HIP 40420 |
9.91 |
| 2026-05-20 12:00 |
08:14:30.49 |
+15:04:15.0 |
HIP 40420 |
9.24 |
| 2026-05-21 00:00 |
08:14:33.31 |
+15:04:11.2 |
HIP 40420 |
8.57 |
| 2026-05-21 12:00 |
08:14:36.18 |
+15:04:07.2 |
HIP 40420 |
7.87 |
| 2026-05-22 00:00 |
08:14:39.10 |
+15:04:02.9 |
HIP 40420 |
7.17 |
| 2026-05-22 12:00 |
08:14:42.07 |
+15:03:58.5 |
HIP 40420 |
6.46 |
| 2026-05-23 00:00 |
08:14:45.10 |
+15:03:53.9 |
HIP 40420 |
5.73 |
| 2026-05-23 12:00 |
08:14:48.17 |
+15:03:49.0 |
HIP 40420 |
4.99 |
| 2026-05-24 00:00 |
08:14:51.29 |
+15:03:43.9 |
HIP 40420 |
4.25 |
| 2026-05-24 12:00 |
08:14:54.46 |
+15:03:38.6 |
HIP 40420 |
3.50 |
| 2026-05-25 00:00 |
08:14:57.68 |
+15:03:33.2 |
HIP 40420 |
2.74 |
| 2026-05-25 12:00 |
08:15:00.94 |
+15:03:27.5 |
HIP 40420 |
2.00 |
| 2026-05-26 00:00 |
08:15:04.26 |
+15:03:21.6 |
HIP 40420 |
1.30 |
| 2026-05-26 12:00 |
08:15:07.62 |
+15:03:15.5 |
HIP 40420 |
0.84 |
| 2026-05-27 00:00 |
08:15:11.03 |
+15:03:09.2 |
HIP 40420 |
1.02 |
| 2026-05-27 12:00 |
08:15:14.48 |
+15:03:02.6 |
HIP 40420 |
1.67 |
| 2026-05-28 00:00 |
08:15:17.98 |
+15:02:55.9 |
HIP 40420 |
2.45 |
| 2026-05-28 12:00 |
08:15:21.53 |
+15:02:49.0 |
HIP 40420 |
3.28 |
| 2026-05-29 00:00 |
08:15:25.12 |
+15:02:41.9 |
HIP 40420 |
4.13 |
| 2026-05-29 12:00 |
08:15:28.76 |
+15:02:34.5 |
HIP 40420 |
5.01 |
| 2026-05-30 00:00 |
08:15:32.44 |
+15:02:27.0 |
HIP 40420 |
5.89 |
| 2026-05-30 12:00 |
08:15:36.17 |
+15:02:19.3 |
HIP 40420 |
6.79 |
| 2026-05-31 00:00 |
08:15:39.94 |
+15:02:11.4 |
HIP 40420 |
7.71 |
| 2026-05-31 12:00 |
08:15:43.76 |
+15:02:03.2 |
HIP 40420 |
8.63 |
| 2026-06-01 00:00 |
08:15:47.62 |
+15:01:54.9 |
HIP 40420 |
9.57 |
| 2026-06-01 12:00 |
08:15:51.52 |
+15:01:46.4 |
HIP 40420 |
10.52 |
| 2026-06-02 00:00 |
08:15:55.46 |
+15:01:37.7 |
HIP 40420 |
11.48 |