メタデータ
| 項目 |
値 |
| Designation |
421P/McNaught |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2009-09-09T00:24:44.127360Z |
| Orbit solution date (soln_date, UTC) |
2023-04-24T23:44:12Z |
| Obs used |
96 |
| NEO |
- |
| M1 |
13.700 |
| K1 |
13.250 |
| PC |
0.030 |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2010-11-09.0000000 |
| e |
0.67538400 |
| q (au) |
1.649202 |
| a (au) |
5.080472 |
| i (deg) |
10.094478 |
| Ω (om, deg) |
55.683595 |
| ω (w, deg) |
259.900711 |
| M (ma, deg) |
36.664020 |
等級
散乱 + 全体線形
$$
M_a = (18.549 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
18.549 |
| n |
2.000 |
| gf |
0.986 |
| gb |
-0.500 |
| k |
0.830 |
| δ90 |
7.395 |
| 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 |
09:10:37.23 |
+25:30:23.3 |
HIP 45105 |
11.33 |
| 2026-07-29 12:00 |
09:10:52.68 |
+25:29:16.4 |
HIP 45105 |
7.75 |
| 2026-07-30 00:00 |
09:11:08.15 |
+25:28:09.5 |
HIP 45105 |
4.28 |
| 2026-07-30 12:00 |
09:11:23.63 |
+25:27:02.7 |
HIP 45105 |
1.89 |
| 2026-07-31 00:00 |
09:11:39.11 |
+25:25:56.0 |
HIP 45105 |
3.96 |
| 2026-07-31 12:00 |
09:11:54.60 |
+25:24:49.3 |
HIP 45105 |
7.40 |
| 2026-08-01 00:00 |
09:12:10.10 |
+25:23:42.8 |
HIP 45105 |
10.99 |
| 2026-08-01 12:00 |
09:12:25.61 |
+25:22:36.4 |
HIP 45260 |
14.22 |
| 2026-08-02 00:00 |
09:12:41.12 |
+25:21:30.0 |
HIP 45260 |
11.31 |
| 2026-08-02 12:00 |
09:12:56.64 |
+25:20:23.8 |
HIP 45260 |
8.99 |
| 2026-08-03 00:00 |
09:13:12.17 |
+25:19:17.7 |
HIP 45260 |
7.78 |
| 2026-08-03 12:00 |
09:13:27.70 |
+25:18:11.7 |
HIP 45278 |
4.36 |
| 2026-08-04 00:00 |
09:13:43.23 |
+25:17:05.8 |
HIP 45278 |
1.85 |
| 2026-08-04 12:00 |
09:13:58.77 |
+25:16:00.0 |
HIP 45316 |
2.80 |
| 2026-08-05 00:00 |
09:14:14.31 |
+25:14:54.3 |
HIP 45316 |
2.88 |
| 2026-08-05 12:00 |
09:14:29.86 |
+25:13:48.7 |
HIP 45316 |
5.99 |
| 2026-08-06 00:00 |
09:14:45.40 |
+25:12:43.3 |
HIP 45316 |
9.52 |
| 2026-08-06 12:00 |
09:15:00.95 |
+25:11:37.9 |
HIP 45316 |
13.13 |
| 2026-08-07 00:00 |
09:15:16.50 |
+25:10:32.7 |
HIP 45349 |
14.77 |
| 2026-08-07 12:00 |
09:15:32.05 |
+25:09:27.6 |
HIP 45349 |
16.97 |
| 2026-08-08 00:00 |
09:15:47.60 |
+25:08:22.7 |
HIP 45349 |
19.62 |
| 2026-08-08 12:00 |
09:16:03.15 |
+25:07:17.9 |
HIP 45349 |
22.57 |
| 2026-08-09 00:00 |
09:16:18.69 |
+25:06:13.2 |
HIP 45349 |
25.70 |
| 2026-08-09 12:00 |
09:16:34.24 |
+25:05:08.6 |
HIP 45665 |
27.20 |
| 2026-08-10 00:00 |
09:16:49.78 |
+25:04:04.2 |
HIP 45665 |
24.19 |
| 2026-08-10 12:00 |
09:17:05.32 |
+25:03:00.0 |
HIP 45665 |
21.39 |
| 2026-08-11 00:00 |
09:17:20.86 |
+25:01:55.9 |
HIP 45665 |
18.89 |
| 2026-08-11 12:00 |
09:17:36.39 |
+25:00:51.9 |
HIP 45665 |
16.82 |
| 2026-08-12 00:00 |
09:17:51.91 |
+24:59:48.1 |
HIP 45665 |
15.37 |
| 2026-08-12 12:00 |
09:18:07.43 |
+24:58:44.5 |
HIP 45665 |
14.71 |
| 2026-08-13 00:00 |
09:18:22.95 |
+24:57:41.0 |
HIP 45665 |
14.94 |
| 2026-08-13 12:00 |
09:18:38.45 |
+24:56:37.7 |
HIP 45665 |
16.03 |
| 2026-08-14 00:00 |
09:18:53.95 |
+24:55:34.5 |
HIP 45739 |
17.42 |
| 2026-08-14 12:00 |
09:19:09.44 |
+24:54:31.6 |
HIP 45739 |
17.08 |
| 2026-08-15 00:00 |
09:19:24.92 |
+24:53:28.8 |
HIP 45739 |
17.51 |
| 2026-08-15 12:00 |
09:19:40.39 |
+24:52:26.1 |
HIP 45739 |
18.67 |
| 2026-08-16 00:00 |
09:19:55.85 |
+24:51:23.7 |
HIP 45739 |
20.41 |
| 2026-08-16 12:00 |
09:20:11.30 |
+24:50:21.4 |
HIP 45739 |
22.62 |
| 2026-08-17 00:00 |
09:20:26.74 |
+24:49:19.4 |
HIP 45869 |
22.77 |
| 2026-08-17 12:00 |
09:20:42.17 |
+24:48:17.5 |
HIP 45869 |
22.46 |
| 2026-08-18 00:00 |
09:20:57.58 |
+24:47:15.8 |
HIP 45869 |
22.74 |
| 2026-08-18 12:00 |
09:21:12.98 |
+24:46:14.3 |
HIP 45869 |
23.58 |
| 2026-08-19 00:00 |
09:21:28.36 |
+24:45:13.0 |
HIP 45869 |
24.93 |