メタデータ
| 項目 |
値 |
| Designation |
C/2021 C3 (Catalina) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-02-12T10:38:30.753600Z |
| Orbit solution date (soln_date, UTC) |
2024-06-21T13:42:16Z |
| Obs used |
363 |
| NEO |
- |
| M1 |
16.100 |
| K1 |
4.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-02-07T11:02:01.017600Z |
| Discovery magnitude (MPC) |
19.15 G |
| Discovery observatory (MPC) |
703 · University of Arizona Catalina Sky Survey |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2021-03-28.0000000 |
| e |
0.96405640 |
| q (au) |
2.276500 |
| a (au) |
63.335351 |
| i (deg) |
122.161615 |
| Ω (om, deg) |
181.919832 |
| ω (w, deg) |
357.151666 |
| M (ma, deg) |
0.085170 |
等級
散乱 + 全体線形
$$
M_a = (17.520 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
17.520 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.650 |
| 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 |
| 2021-02-13 |
2021-06-09 |
-16.5522 |
+5.942 |
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 |
00:48:33.47 |
+48:36:30.9 |
HIP 4042 |
39.43 |
| 2026-09-20 12:00 |
00:48:22.15 |
+48:36:01.6 |
HIP 3504 |
40.92 |
| 2026-09-21 00:00 |
00:48:10.80 |
+48:35:31.4 |
HIP 3504 |
39.02 |
| 2026-09-21 12:00 |
00:47:59.43 |
+48:35:00.5 |
HIP 3504 |
37.12 |
| 2026-09-22 00:00 |
00:47:48.03 |
+48:34:28.6 |
HIP 3504 |
35.22 |
| 2026-09-22 12:00 |
00:47:36.62 |
+48:33:56.0 |
HIP 3504 |
33.31 |
| 2026-09-23 00:00 |
00:47:25.18 |
+48:33:22.5 |
HIP 3504 |
31.40 |
| 2026-09-23 12:00 |
00:47:13.73 |
+48:32:48.2 |
HIP 3504 |
29.48 |
| 2026-09-24 00:00 |
00:47:02.25 |
+48:32:13.0 |
HIP 3504 |
27.56 |
| 2026-09-24 12:00 |
00:46:50.77 |
+48:31:37.0 |
HIP 3504 |
25.65 |
| 2026-09-25 00:00 |
00:46:39.26 |
+48:31:00.2 |
HIP 3504 |
23.74 |
| 2026-09-25 12:00 |
00:46:27.74 |
+48:30:22.6 |
HIP 3504 |
21.83 |
| 2026-09-26 00:00 |
00:46:16.21 |
+48:29:44.1 |
HIP 3504 |
19.94 |
| 2026-09-26 12:00 |
00:46:04.66 |
+48:29:04.8 |
HIP 3504 |
18.05 |
| 2026-09-27 00:00 |
00:45:53.10 |
+48:28:24.6 |
HIP 3504 |
16.20 |
| 2026-09-27 12:00 |
00:45:41.53 |
+48:27:43.7 |
HIP 3504 |
14.37 |
| 2026-09-28 00:00 |
00:45:29.95 |
+48:27:01.9 |
HIP 3504 |
12.61 |
| 2026-09-28 12:00 |
00:45:18.37 |
+48:26:19.3 |
HIP 3504 |
10.92 |
| 2026-09-29 00:00 |
00:45:06.77 |
+48:25:35.8 |
HIP 3504 |
9.37 |
| 2026-09-29 12:00 |
00:44:55.17 |
+48:24:51.6 |
HIP 3504 |
8.03 |
| 2026-09-30 00:00 |
00:44:43.57 |
+48:24:06.5 |
HIP 3504 |
7.05 |
| 2026-09-30 12:00 |
00:44:31.95 |
+48:23:20.6 |
HIP 3504 |
6.57 |
| 2026-10-01 00:00 |
00:44:20.34 |
+48:22:33.9 |
HIP 3504 |
6.71 |
| 2026-10-01 12:00 |
00:44:08.72 |
+48:21:46.4 |
HIP 3504 |
7.46 |
| 2026-10-02 00:00 |
00:43:57.10 |
+48:20:58.0 |
HIP 3504 |
8.65 |
| 2026-10-02 12:00 |
00:43:45.49 |
+48:20:08.9 |
HIP 3504 |
10.13 |
| 2026-10-03 00:00 |
00:43:33.87 |
+48:19:18.9 |
HIP 3462 |
11.20 |
| 2026-10-03 12:00 |
00:43:22.25 |
+48:18:28.1 |
HIP 3462 |
11.99 |
| 2026-10-04 00:00 |
00:43:10.64 |
+48:17:36.6 |
HIP 3462 |
13.07 |
| 2026-10-04 12:00 |
00:42:59.03 |
+48:16:44.2 |
HIP 3462 |
14.38 |
| 2026-10-05 00:00 |
00:42:47.43 |
+48:15:51.0 |
HIP 3462 |
15.86 |
| 2026-10-05 12:00 |
00:42:35.83 |
+48:14:57.0 |
HIP 3462 |
17.47 |
| 2026-10-06 00:00 |
00:42:24.24 |
+48:14:02.3 |
HIP 3462 |
19.18 |
| 2026-10-06 12:00 |
00:42:12.66 |
+48:13:06.7 |
HIP 3462 |
20.97 |
| 2026-10-07 00:00 |
00:42:01.09 |
+48:12:10.3 |
HIP 3462 |
22.82 |
| 2026-10-07 12:00 |
00:41:49.53 |
+48:11:13.2 |
HIP 3462 |
24.71 |
| 2026-10-08 00:00 |
00:41:37.99 |
+48:10:15.3 |
HIP 3462 |
26.64 |
| 2026-10-08 12:00 |
00:41:26.45 |
+48:09:16.6 |
HIP 3111 |
26.04 |
| 2026-10-09 00:00 |
00:41:14.93 |
+48:08:17.1 |
HIP 3111 |
25.48 |
| 2026-10-09 12:00 |
00:41:03.43 |
+48:07:16.9 |
HIP 3111 |
25.11 |
| 2026-10-10 00:00 |
00:40:51.94 |
+48:06:15.9 |
HIP 3111 |
24.94 |
| 2026-10-10 12:00 |
00:40:40.47 |
+48:05:14.1 |
HIP 3111 |
24.96 |
| 2026-10-11 00:00 |
00:40:29.02 |
+48:04:11.6 |
HIP 3111 |
25.18 |