メタデータ
| 項目 |
値 |
| Designation |
C/2020 U3 (Rankin) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-02-05T23:23:23.781120Z |
| Orbit solution date (soln_date, UTC) |
2023-04-24T19:06:41Z |
| Obs used |
178 |
| NEO |
- |
| M1 |
9.700 |
| K1 |
22.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2020-10-22T03:37:43.852800Z |
| Discovery magnitude (MPC) |
20.14 G |
| Discovery observatory (MPC) |
G96 · University of Arizona Mt. Lemmon Survey |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2020-11-22.0000000 |
| e |
0.96479330 |
| q (au) |
2.276177 |
| a (au) |
64.651799 |
| i (deg) |
30.176991 |
| Ω (om, deg) |
282.679092 |
| ω (w, deg) |
124.262013 |
| M (ma, deg) |
359.855954 |
等級
散乱 + 全体線形
$$
M_a = (11.589 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
11.589 |
| 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
残差 (区間線形)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| 開始日 (UTC) |
終了日 (UTC) |
a |
b |
| 2020-07-21 |
2021-02-05 |
+3.5360 |
-1.291 |
| 2021-02-07 |
2021-10-31 |
+2.0235 |
-1.913 |
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 |
11:20:29.99 |
-26:27:10.8 |
HIP 55385 |
17.75 |
| 2026-09-20 12:00 |
11:20:38.33 |
-26:28:04.4 |
HIP 55385 |
18.80 |
| 2026-09-21 00:00 |
11:20:46.67 |
-26:28:58.5 |
HIP 55385 |
20.01 |
| 2026-09-21 12:00 |
11:20:54.99 |
-26:29:52.9 |
HIP 55385 |
21.36 |
| 2026-09-22 00:00 |
11:21:03.30 |
-26:30:47.7 |
HIP 55385 |
22.82 |
| 2026-09-22 12:00 |
11:21:11.60 |
-26:31:42.9 |
HIP 55385 |
24.37 |
| 2026-09-23 00:00 |
11:21:19.89 |
-26:32:38.4 |
HIP 55385 |
26.01 |
| 2026-09-23 12:00 |
11:21:28.16 |
-26:33:34.3 |
HIP 55385 |
27.70 |
| 2026-09-24 00:00 |
11:21:36.42 |
-26:34:30.5 |
HIP 55385 |
29.45 |
| 2026-09-24 12:00 |
11:21:44.67 |
-26:35:27.1 |
HIP 55385 |
31.24 |
| 2026-09-25 00:00 |
11:21:52.91 |
-26:36:24.1 |
HIP 55385 |
33.06 |
| 2026-09-25 12:00 |
11:22:01.13 |
-26:37:21.4 |
HIP 55640 |
32.07 |
| 2026-09-26 00:00 |
11:22:09.34 |
-26:38:19.1 |
HIP 55640 |
30.04 |
| 2026-09-26 12:00 |
11:22:17.53 |
-26:39:17.1 |
HIP 55640 |
28.02 |
| 2026-09-27 00:00 |
11:22:25.71 |
-26:40:15.4 |
HIP 55640 |
26.00 |
| 2026-09-27 12:00 |
11:22:33.88 |
-26:41:14.1 |
HIP 55640 |
24.00 |
| 2026-09-28 00:00 |
11:22:42.02 |
-26:42:13.1 |
HIP 55640 |
22.00 |
| 2026-09-28 12:00 |
11:22:50.16 |
-26:43:12.5 |
HIP 55640 |
20.01 |
| 2026-09-29 00:00 |
11:22:58.27 |
-26:44:12.1 |
HIP 55640 |
18.04 |
| 2026-09-29 12:00 |
11:23:06.37 |
-26:45:12.2 |
HIP 55640 |
16.10 |
| 2026-09-30 00:00 |
11:23:14.45 |
-26:46:12.5 |
HIP 55640 |
14.18 |
| 2026-09-30 12:00 |
11:23:22.51 |
-26:47:13.2 |
HIP 55640 |
12.31 |
| 2026-10-01 00:00 |
11:23:30.56 |
-26:48:14.2 |
HIP 55640 |
10.52 |
| 2026-10-01 12:00 |
11:23:38.59 |
-26:49:15.5 |
HIP 55640 |
8.83 |
| 2026-10-02 00:00 |
11:23:46.59 |
-26:50:17.1 |
HIP 55640 |
7.34 |
| 2026-10-02 12:00 |
11:23:54.58 |
-26:51:19.1 |
HIP 55640 |
6.18 |
| 2026-10-03 00:00 |
11:24:02.55 |
-26:52:21.4 |
HIP 55640 |
5.55 |
| 2026-10-03 12:00 |
11:24:10.50 |
-26:53:23.9 |
HIP 55640 |
5.65 |
| 2026-10-04 00:00 |
11:24:18.43 |
-26:54:26.8 |
HIP 55640 |
6.43 |
| 2026-10-04 12:00 |
11:24:26.34 |
-26:55:30.0 |
HIP 55668 |
5.74 |
| 2026-10-05 00:00 |
11:24:34.22 |
-26:56:33.5 |
HIP 55668 |
5.24 |
| 2026-10-05 12:00 |
11:24:42.09 |
-26:57:37.3 |
HIP 55668 |
5.50 |
| 2026-10-06 00:00 |
11:24:49.93 |
-26:58:41.4 |
HIP 55668 |
6.43 |
| 2026-10-06 12:00 |
11:24:57.75 |
-26:59:45.7 |
HIP 55668 |
7.79 |
| 2026-10-07 00:00 |
11:25:05.54 |
-27:00:50.4 |
HIP 55742 |
8.94 |
| 2026-10-07 12:00 |
11:25:13.31 |
-27:01:55.4 |
HIP 55742 |
9.70 |
| 2026-10-08 00:00 |
11:25:21.06 |
-27:03:00.6 |
HIP 55742 |
10.80 |
| 2026-10-08 12:00 |
11:25:28.78 |
-27:04:06.1 |
HIP 55742 |
12.15 |
| 2026-10-09 00:00 |
11:25:36.48 |
-27:05:11.9 |
HIP 55742 |
13.68 |
| 2026-10-09 12:00 |
11:25:44.16 |
-27:06:17.9 |
HIP 55742 |
15.33 |
| 2026-10-10 00:00 |
11:25:51.80 |
-27:07:24.3 |
HIP 55742 |
17.06 |
| 2026-10-10 12:00 |
11:25:59.42 |
-27:08:30.9 |
HIP 55742 |
18.85 |
| 2026-10-11 00:00 |
11:26:07.02 |
-27:09:37.7 |
HIP 55742 |
20.68 |