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 · 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) |
| 2026-05-12 00:00 |
00:56:59.95 |
+45:40:05.1 |
HIP 4364 |
11.19 |
| 2026-05-12 12:00 |
00:57:07.69 |
+45:40:59.6 |
HIP 4501 |
10.90 |
| 2026-05-13 00:00 |
00:57:15.39 |
+45:41:54.4 |
HIP 4501 |
9.45 |
| 2026-05-13 12:00 |
00:57:23.04 |
+45:42:49.5 |
HIP 4501 |
8.07 |
| 2026-05-14 00:00 |
00:57:30.64 |
+45:43:44.9 |
HIP 4501 |
6.80 |
| 2026-05-14 12:00 |
00:57:38.19 |
+45:44:40.6 |
HIP 4501 |
5.69 |
| 2026-05-15 00:00 |
00:57:45.70 |
+45:45:36.6 |
HIP 4501 |
4.87 |
| 2026-05-15 12:00 |
00:57:53.15 |
+45:46:32.8 |
HIP 4501 |
4.48 |
| 2026-05-16 00:00 |
00:58:00.55 |
+45:47:29.3 |
HIP 4501 |
4.64 |
| 2026-05-16 12:00 |
00:58:07.91 |
+45:48:26.1 |
HIP 4501 |
5.29 |
| 2026-05-17 00:00 |
00:58:15.21 |
+45:49:23.2 |
HIP 4501 |
6.27 |
| 2026-05-17 12:00 |
00:58:22.46 |
+45:50:20.5 |
HIP 4501 |
7.46 |
| 2026-05-18 00:00 |
00:58:29.66 |
+45:51:18.1 |
HIP 4501 |
8.76 |
| 2026-05-18 12:00 |
00:58:36.81 |
+45:52:15.9 |
HIP 4501 |
10.13 |
| 2026-05-19 00:00 |
00:58:43.90 |
+45:53:14.0 |
HIP 4501 |
11.55 |
| 2026-05-19 12:00 |
00:58:50.94 |
+45:54:12.3 |
HIP 4501 |
12.99 |
| 2026-05-20 00:00 |
00:58:57.92 |
+45:55:10.9 |
HIP 4501 |
14.45 |
| 2026-05-20 12:00 |
00:59:04.85 |
+45:56:09.7 |
HIP 4501 |
15.92 |
| 2026-05-21 00:00 |
00:59:11.73 |
+45:57:08.7 |
HIP 4501 |
17.40 |
| 2026-05-21 12:00 |
00:59:18.55 |
+45:58:07.9 |
HIP 4501 |
18.88 |
| 2026-05-22 00:00 |
00:59:25.31 |
+45:59:07.4 |
HIP 4734 |
18.04 |
| 2026-05-22 12:00 |
00:59:32.02 |
+46:00:07.1 |
HIP 4734 |
16.51 |
| 2026-05-23 00:00 |
00:59:38.66 |
+46:01:07.0 |
HIP 4734 |
14.99 |
| 2026-05-23 12:00 |
00:59:45.26 |
+46:02:07.1 |
HIP 4734 |
13.47 |
| 2026-05-24 00:00 |
00:59:51.79 |
+46:03:07.4 |
HIP 4734 |
11.97 |
| 2026-05-24 12:00 |
00:59:58.27 |
+46:04:07.9 |
HIP 4734 |
10.47 |
| 2026-05-25 00:00 |
01:00:04.68 |
+46:05:08.6 |
HIP 4734 |
8.98 |
| 2026-05-25 12:00 |
01:00:11.04 |
+46:06:09.5 |
HIP 4734 |
7.51 |
| 2026-05-26 00:00 |
01:00:17.34 |
+46:07:10.6 |
HIP 4734 |
6.06 |
| 2026-05-26 12:00 |
01:00:23.58 |
+46:08:11.8 |
HIP 4734 |
4.64 |
| 2026-05-27 00:00 |
01:00:29.75 |
+46:09:13.3 |
HIP 4734 |
3.29 |
| 2026-05-27 12:00 |
01:00:35.87 |
+46:10:14.9 |
HIP 4734 |
2.15 |
| 2026-05-28 00:00 |
01:00:41.93 |
+46:11:16.7 |
HIP 4734 |
1.66 |
| 2026-05-28 12:00 |
01:00:47.92 |
+46:12:18.6 |
HIP 4734 |
2.29 |
| 2026-05-29 00:00 |
01:00:53.85 |
+46:13:20.7 |
HIP 4734 |
3.46 |
| 2026-05-29 12:00 |
01:00:59.72 |
+46:14:23.0 |
HIP 4734 |
4.80 |
| 2026-05-30 00:00 |
01:01:05.53 |
+46:15:25.4 |
HIP 4734 |
6.18 |
| 2026-05-30 12:00 |
01:01:11.27 |
+46:16:28.0 |
HIP 4734 |
7.58 |
| 2026-05-31 00:00 |
01:01:16.95 |
+46:17:30.7 |
HIP 4734 |
8.99 |
| 2026-05-31 12:00 |
01:01:22.57 |
+46:18:33.5 |
HIP 4734 |
10.40 |
| 2026-06-01 00:00 |
01:01:28.12 |
+46:19:36.5 |
HIP 4734 |
11.81 |
| 2026-06-01 12:00 |
01:01:33.61 |
+46:20:39.7 |
HIP 4734 |
13.22 |
| 2026-06-02 00:00 |
01:01:39.03 |
+46:21:42.9 |
HIP 4734 |
14.63 |