メタデータ
| 項目 |
値 |
| Designation |
C/2005 S4 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2007-07-18T15:31:21.316800Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:53Z |
| Obs used |
580 |
| NEO |
- |
| M1 |
9.900 |
| K1 |
5.500 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2007-06-06.0000000 |
| e |
0.99897119 |
| q (au) |
5.850108 |
| a (au) |
5686.269098 |
| i (deg) |
107.958958 |
| Ω (om, deg) |
318.290291 |
| ω (w, deg) |
31.453945 |
| M (ma, deg) |
359.999902 |
等級
散乱 + 全体線形
$$
M_a = (6.966 + 3.745\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
6.966 |
| n |
3.745 |
| gf |
0.995 |
| gb |
-0.897 |
| k |
0.999 |
| 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 |
| 2005-07-27 |
2007-07-16 |
-1.0253 |
+0.679 |
| 2007-07-19 |
2008-10-06 |
+18.7523 |
-14.647 |
| 2008-10-06 |
2009-07-23 |
+4.6293 |
-3.301 |
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) |
| 2026-03-26 00:00 |
10:03:42.84 |
+29:25:01.3 |
HIP 49398 |
26.85 |
| 2026-03-26 12:00 |
10:03:39.54 |
+29:25:02.2 |
HIP 49398 |
27.32 |
| 2026-03-27 00:00 |
10:03:36.26 |
+29:25:02.8 |
HIP 49398 |
27.80 |
| 2026-03-27 12:00 |
10:03:33.01 |
+29:25:03.3 |
HIP 49398 |
28.30 |
| 2026-03-28 00:00 |
10:03:29.77 |
+29:25:03.5 |
HIP 49398 |
28.80 |
| 2026-03-28 12:00 |
10:03:26.56 |
+29:25:03.5 |
HIP 49109 |
28.86 |
| 2026-03-29 00:00 |
10:03:23.37 |
+29:25:03.3 |
HIP 49109 |
28.21 |
| 2026-03-29 12:00 |
10:03:20.20 |
+29:25:02.9 |
HIP 49109 |
27.57 |
| 2026-03-30 00:00 |
10:03:17.05 |
+29:25:02.4 |
HIP 49109 |
26.94 |
| 2026-03-30 12:00 |
10:03:13.93 |
+29:25:01.6 |
HIP 49109 |
26.31 |
| 2026-03-31 00:00 |
10:03:10.83 |
+29:25:00.6 |
HIP 49109 |
25.70 |
| 2026-03-31 12:00 |
10:03:07.75 |
+29:24:59.4 |
HIP 49109 |
25.09 |
| 2026-04-01 00:00 |
10:03:04.69 |
+29:24:58.0 |
HIP 49109 |
24.49 |
| 2026-04-01 12:00 |
10:03:01.66 |
+29:24:56.4 |
HIP 49109 |
23.90 |
| 2026-04-02 00:00 |
10:02:58.65 |
+29:24:54.6 |
HIP 49109 |
23.33 |
| 2026-04-02 12:00 |
10:02:55.66 |
+29:24:52.6 |
HIP 49109 |
22.76 |
| 2026-04-03 00:00 |
10:02:52.70 |
+29:24:50.4 |
HIP 49109 |
22.20 |
| 2026-04-03 12:00 |
10:02:49.76 |
+29:24:48.0 |
HIP 49109 |
21.65 |
| 2026-04-04 00:00 |
10:02:46.84 |
+29:24:45.3 |
HIP 49109 |
21.12 |
| 2026-04-04 12:00 |
10:02:43.95 |
+29:24:42.5 |
HIP 49109 |
20.60 |
| 2026-04-05 00:00 |
10:02:41.08 |
+29:24:39.5 |
HIP 49109 |
20.09 |
| 2026-04-05 12:00 |
10:02:38.24 |
+29:24:36.3 |
HIP 49109 |
19.59 |
| 2026-04-06 00:00 |
10:02:35.42 |
+29:24:32.9 |
HIP 49109 |
19.10 |
| 2026-04-06 12:00 |
10:02:32.63 |
+29:24:29.3 |
HIP 49109 |
18.63 |
| 2026-04-07 00:00 |
10:02:29.86 |
+29:24:25.5 |
HIP 49109 |
18.18 |
| 2026-04-07 12:00 |
10:02:27.12 |
+29:24:21.5 |
HIP 49109 |
17.74 |
| 2026-04-08 00:00 |
10:02:24.40 |
+29:24:17.2 |
HIP 49109 |
17.32 |
| 2026-04-08 12:00 |
10:02:21.71 |
+29:24:12.8 |
HIP 49109 |
16.91 |
| 2026-04-09 00:00 |
10:02:19.04 |
+29:24:08.2 |
HIP 49109 |
16.52 |
| 2026-04-09 12:00 |
10:02:16.40 |
+29:24:03.4 |
HIP 49109 |
16.15 |
| 2026-04-10 00:00 |
10:02:13.79 |
+29:23:58.4 |
HIP 49109 |
15.80 |
| 2026-04-10 12:00 |
10:02:11.20 |
+29:23:53.2 |
HIP 49109 |
15.46 |
| 2026-04-11 00:00 |
10:02:08.64 |
+29:23:47.8 |
HIP 49109 |
15.15 |
| 2026-04-11 12:00 |
10:02:06.11 |
+29:23:42.2 |
HIP 49109 |
14.86 |
| 2026-04-12 00:00 |
10:02:03.60 |
+29:23:36.4 |
HIP 49109 |
14.59 |
| 2026-04-12 12:00 |
10:02:01.12 |
+29:23:30.4 |
HIP 49109 |
14.34 |
| 2026-04-13 00:00 |
10:01:58.67 |
+29:23:24.2 |
HIP 49109 |
14.12 |
| 2026-04-13 12:00 |
10:01:56.24 |
+29:23:17.8 |
HIP 49109 |
13.92 |
| 2026-04-14 00:00 |
10:01:53.84 |
+29:23:11.2 |
HIP 49109 |
13.74 |
| 2026-04-14 12:00 |
10:01:51.47 |
+29:23:04.4 |
HIP 49109 |
13.59 |
| 2026-04-15 00:00 |
10:01:49.12 |
+29:22:57.5 |
HIP 49109 |
13.46 |
| 2026-04-15 12:00 |
10:01:46.81 |
+29:22:50.3 |
HIP 49109 |
13.36 |
| 2026-04-16 00:00 |
10:01:44.52 |
+29:22:42.9 |
HIP 49109 |
13.28 |