メタデータ
| 項目 |
値 |
| Designation |
C/1919 Q2 (Metcalf) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1919-12-07T19:37:10.358400Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:02Z |
| Obs used |
18 |
| NEO |
- |
| M1 |
5.100 |
| K1 |
11.500 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
1919-09-18.0000000 |
| e |
0.99977859 |
| q (au) |
1.115204 |
| a (au) |
5036.797426 |
| i (deg) |
46.383158 |
| Ω (om, deg) |
122.097279 |
| ω (w, deg) |
185.764445 |
| M (ma, deg) |
359.999777 |
等級
散乱 + 全体線形
$$
M_a = (6.671 + 5.125\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
6.671 |
| n |
5.125 |
| gf |
1.000 |
| gb |
-1.000 |
| 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
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
08:00:13.31 |
+16:56:34.6 |
HIP 39046 |
15.23 |
| 2026-07-29 12:00 |
08:00:14.25 |
+16:56:31.8 |
HIP 39046 |
15.41 |
| 2026-07-30 00:00 |
08:00:15.20 |
+16:56:29.1 |
HIP 39046 |
15.58 |
| 2026-07-30 12:00 |
08:00:16.15 |
+16:56:26.3 |
HIP 39046 |
15.76 |
| 2026-07-31 00:00 |
08:00:17.09 |
+16:56:23.5 |
HIP 39226 |
15.80 |
| 2026-07-31 12:00 |
08:00:18.04 |
+16:56:20.8 |
HIP 39226 |
15.58 |
| 2026-08-01 00:00 |
08:00:18.98 |
+16:56:18.0 |
HIP 39226 |
15.36 |
| 2026-08-01 12:00 |
08:00:19.92 |
+16:56:15.2 |
HIP 39226 |
15.14 |
| 2026-08-02 00:00 |
08:00:20.86 |
+16:56:12.4 |
HIP 39226 |
14.91 |
| 2026-08-02 12:00 |
08:00:21.79 |
+16:56:09.6 |
HIP 39226 |
14.69 |
| 2026-08-03 00:00 |
08:00:22.73 |
+16:56:06.8 |
HIP 39226 |
14.47 |
| 2026-08-03 12:00 |
08:00:23.66 |
+16:56:04.0 |
HIP 39226 |
14.25 |
| 2026-08-04 00:00 |
08:00:24.60 |
+16:56:01.2 |
HIP 39226 |
14.03 |
| 2026-08-04 12:00 |
08:00:25.53 |
+16:55:58.4 |
HIP 39226 |
13.81 |
| 2026-08-05 00:00 |
08:00:26.46 |
+16:55:55.6 |
HIP 39226 |
13.60 |
| 2026-08-05 12:00 |
08:00:27.38 |
+16:55:52.8 |
HIP 39226 |
13.38 |
| 2026-08-06 00:00 |
08:00:28.31 |
+16:55:50.0 |
HIP 39226 |
13.16 |
| 2026-08-06 12:00 |
08:00:29.23 |
+16:55:47.2 |
HIP 39226 |
12.95 |
| 2026-08-07 00:00 |
08:00:30.15 |
+16:55:44.4 |
HIP 39226 |
12.73 |
| 2026-08-07 12:00 |
08:00:31.07 |
+16:55:41.6 |
HIP 39226 |
12.52 |
| 2026-08-08 00:00 |
08:00:31.99 |
+16:55:38.8 |
HIP 39226 |
12.30 |
| 2026-08-08 12:00 |
08:00:32.90 |
+16:55:36.0 |
HIP 39226 |
12.09 |
| 2026-08-09 00:00 |
08:00:33.81 |
+16:55:33.1 |
HIP 39226 |
11.88 |
| 2026-08-09 12:00 |
08:00:34.72 |
+16:55:30.3 |
HIP 39226 |
11.67 |
| 2026-08-10 00:00 |
08:00:35.63 |
+16:55:27.5 |
HIP 39226 |
11.46 |
| 2026-08-10 12:00 |
08:00:36.53 |
+16:55:24.7 |
HIP 39226 |
11.25 |
| 2026-08-11 00:00 |
08:00:37.43 |
+16:55:21.9 |
HIP 39226 |
11.05 |
| 2026-08-11 12:00 |
08:00:38.33 |
+16:55:19.1 |
HIP 39226 |
10.84 |
| 2026-08-12 00:00 |
08:00:39.23 |
+16:55:16.3 |
HIP 39226 |
10.64 |
| 2026-08-12 12:00 |
08:00:40.12 |
+16:55:13.5 |
HIP 39226 |
10.43 |
| 2026-08-13 00:00 |
08:00:41.01 |
+16:55:10.6 |
HIP 39226 |
10.23 |
| 2026-08-13 12:00 |
08:00:41.90 |
+16:55:07.8 |
HIP 39226 |
10.03 |
| 2026-08-14 00:00 |
08:00:42.78 |
+16:55:05.0 |
HIP 39226 |
9.83 |
| 2026-08-14 12:00 |
08:00:43.66 |
+16:55:02.2 |
HIP 39226 |
9.64 |
| 2026-08-15 00:00 |
08:00:44.54 |
+16:54:59.4 |
HIP 39226 |
9.44 |
| 2026-08-15 12:00 |
08:00:45.41 |
+16:54:56.6 |
HIP 39226 |
9.25 |
| 2026-08-16 00:00 |
08:00:46.29 |
+16:54:53.8 |
HIP 39226 |
9.05 |
| 2026-08-16 12:00 |
08:00:47.15 |
+16:54:51.0 |
HIP 39226 |
8.86 |
| 2026-08-17 00:00 |
08:00:48.02 |
+16:54:48.2 |
HIP 39226 |
8.67 |
| 2026-08-17 12:00 |
08:00:48.88 |
+16:54:45.5 |
HIP 39226 |
8.49 |
| 2026-08-18 00:00 |
08:00:49.74 |
+16:54:42.7 |
HIP 39226 |
8.30 |
| 2026-08-18 12:00 |
08:00:50.59 |
+16:54:39.9 |
HIP 39226 |
8.12 |
| 2026-08-19 00:00 |
08:00:51.44 |
+16:54:37.1 |
HIP 39226 |
7.94 |