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
$$
M_a = (12.398 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
12.398 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.527 |
| 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 |
-9.0008 |
+3.871 |
| 2020-11-08 |
2020-12-10 |
+15.0549 |
-3.889 |
| 2020-12-10 |
2021-02-27 |
+6.3853 |
-2.568 |
| 2021-03-04 |
2021-04-25 |
+19.0603 |
-2.302 |
| 2021-04-25 |
2021-05-29 |
+5.1563 |
-1.271 |
| 2021-05-29 |
2026-09-11 |
-12.1703 |
+2.502 |
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) |
| 2026-09-20 00:00 |
08:35:44.55 |
+13:42:21.9 |
HIP 42193 |
7.71 |
| 2026-09-20 12:00 |
08:35:48.14 |
+13:41:58.9 |
HIP 42193 |
7.25 |
| 2026-09-21 00:00 |
08:35:51.69 |
+13:41:36.0 |
HIP 42193 |
6.89 |
| 2026-09-21 12:00 |
08:35:55.19 |
+13:41:13.3 |
HIP 42195 |
6.59 |
| 2026-09-22 00:00 |
08:35:58.64 |
+13:40:50.7 |
HIP 42195 |
6.37 |
| 2026-09-22 12:00 |
08:36:02.05 |
+13:40:28.1 |
HIP 42195 |
6.29 |
| 2026-09-23 00:00 |
08:36:05.42 |
+13:40:05.7 |
HIP 42195 |
6.35 |
| 2026-09-23 12:00 |
08:36:08.73 |
+13:39:43.5 |
HIP 42195 |
6.52 |
| 2026-09-24 00:00 |
08:36:12.01 |
+13:39:21.3 |
HIP 42195 |
6.81 |
| 2026-09-24 12:00 |
08:36:15.23 |
+13:38:59.3 |
HIP 42195 |
7.19 |
| 2026-09-25 00:00 |
08:36:18.41 |
+13:38:37.3 |
HIP 42195 |
7.65 |
| 2026-09-25 12:00 |
08:36:21.54 |
+13:38:15.6 |
HIP 42195 |
8.16 |
| 2026-09-26 00:00 |
08:36:24.63 |
+13:37:53.9 |
HIP 42195 |
8.72 |
| 2026-09-26 12:00 |
08:36:27.66 |
+13:37:32.4 |
HIP 42195 |
9.31 |
| 2026-09-27 00:00 |
08:36:30.65 |
+13:37:10.9 |
HIP 42195 |
9.93 |
| 2026-09-27 12:00 |
08:36:33.59 |
+13:36:49.7 |
HIP 42195 |
10.57 |
| 2026-09-28 00:00 |
08:36:36.48 |
+13:36:28.5 |
HIP 42195 |
11.22 |
| 2026-09-28 12:00 |
08:36:39.33 |
+13:36:07.5 |
HIP 42195 |
11.88 |
| 2026-09-29 00:00 |
08:36:42.12 |
+13:35:46.6 |
HIP 42195 |
12.55 |
| 2026-09-29 12:00 |
08:36:44.87 |
+13:35:25.9 |
HIP 42195 |
13.21 |
| 2026-09-30 00:00 |
08:36:47.56 |
+13:35:05.3 |
HIP 42195 |
13.88 |
| 2026-09-30 12:00 |
08:36:50.21 |
+13:34:44.8 |
HIP 42195 |
14.54 |
| 2026-10-01 00:00 |
08:36:52.80 |
+13:34:24.5 |
HIP 42195 |
15.20 |
| 2026-10-01 12:00 |
08:36:55.35 |
+13:34:04.3 |
HIP 42195 |
15.85 |
| 2026-10-02 00:00 |
08:36:57.84 |
+13:33:44.3 |
HIP 42195 |
16.50 |
| 2026-10-02 12:00 |
08:37:00.28 |
+13:33:24.4 |
HIP 42195 |
17.14 |
| 2026-10-03 00:00 |
08:37:02.68 |
+13:33:04.7 |
HIP 42195 |
17.78 |
| 2026-10-03 12:00 |
08:37:05.02 |
+13:32:45.1 |
HIP 42195 |
18.40 |
| 2026-10-04 00:00 |
08:37:07.30 |
+13:32:25.7 |
HIP 42195 |
19.02 |
| 2026-10-04 12:00 |
08:37:09.54 |
+13:32:06.4 |
HIP 42195 |
19.63 |
| 2026-10-05 00:00 |
08:37:11.72 |
+13:31:47.3 |
HIP 42195 |
20.23 |
| 2026-10-05 12:00 |
08:37:13.85 |
+13:31:28.3 |
HIP 42195 |
20.82 |
| 2026-10-06 00:00 |
08:37:15.93 |
+13:31:09.5 |
HIP 42195 |
21.40 |
| 2026-10-06 12:00 |
08:37:17.95 |
+13:30:50.9 |
HIP 42195 |
21.96 |
| 2026-10-07 00:00 |
08:37:19.92 |
+13:30:32.4 |
HIP 42195 |
22.52 |
| 2026-10-07 12:00 |
08:37:21.83 |
+13:30:14.1 |
HIP 42195 |
23.07 |
| 2026-10-08 00:00 |
08:37:23.69 |
+13:29:55.9 |
HIP 42195 |
23.61 |
| 2026-10-08 12:00 |
08:37:25.50 |
+13:29:37.9 |
HIP 42195 |
24.13 |
| 2026-10-09 00:00 |
08:37:27.25 |
+13:29:20.1 |
HIP 42195 |
24.64 |
| 2026-10-09 12:00 |
08:37:28.94 |
+13:29:02.5 |
HIP 42195 |
25.15 |
| 2026-10-10 00:00 |
08:37:30.58 |
+13:28:45.0 |
HIP 42195 |
25.64 |
| 2026-10-10 12:00 |
08:37:32.17 |
+13:28:27.8 |
HIP 42195 |
26.11 |
| 2026-10-11 00:00 |
08:37:33.69 |
+13:28:10.6 |
HIP 42195 |
26.58 |