メタデータ
| 項目 |
値 |
| Designation |
C/2008 A1 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2008-09-29T02:59:09.844800Z |
| Orbit solution date (soln_date, UTC) |
2021-04-16T12:07:02Z |
| Obs used |
906 |
| NEO |
- |
| M1 |
8.100 |
| K1 |
10.000 |
| PC |
0.030 |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2008-09-26.0000000 |
| e |
1.00023047 |
| q (au) |
1.073075 |
| a (au) |
-4655.992023 |
| i (deg) |
82.549175 |
| Ω (om, deg) |
277.883699 |
| ω (w, deg) |
348.473258 |
| M (ma, deg) |
-0.000010 |
等級
散乱 + 全体線形
$$
M_a = (10.584 + 3.102\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
10.584 |
| n |
3.102 |
| gf |
0.998 |
| gb |
-0.500 |
| k |
0.800 |
| δ90 |
8.390 |
| 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 |
| 2008-01-10 |
2008-09-28 |
+4.7194 |
-3.531 |
| 2008-09-29 |
2008-11-02 |
+10.5269 |
-3.006 |
| 2008-11-02 |
2010-01-17 |
+3.3602 |
-1.676 |
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 |
06:30:33.28 |
+53:56:55.7 |
HIP 31080 |
12.44 |
| 2026-09-20 12:00 |
06:30:34.11 |
+53:57:17.2 |
HIP 31080 |
12.68 |
| 2026-09-21 00:00 |
06:30:34.90 |
+53:57:38.8 |
HIP 31080 |
12.93 |
| 2026-09-21 12:00 |
06:30:35.64 |
+53:58:00.4 |
HIP 31080 |
13.18 |
| 2026-09-22 00:00 |
06:30:36.33 |
+53:58:22.1 |
HIP 31080 |
13.45 |
| 2026-09-22 12:00 |
06:30:36.98 |
+53:58:43.9 |
HIP 31080 |
13.73 |
| 2026-09-23 00:00 |
06:30:37.59 |
+53:59:05.7 |
HIP 31080 |
14.01 |
| 2026-09-23 12:00 |
06:30:38.15 |
+53:59:27.5 |
HIP 31080 |
14.30 |
| 2026-09-24 00:00 |
06:30:38.67 |
+53:59:49.4 |
HIP 31080 |
14.60 |
| 2026-09-24 12:00 |
06:30:39.14 |
+54:00:11.4 |
HIP 31080 |
14.91 |
| 2026-09-25 00:00 |
06:30:39.57 |
+54:00:33.4 |
HIP 31080 |
15.22 |
| 2026-09-25 12:00 |
06:30:39.95 |
+54:00:55.4 |
HIP 31080 |
15.54 |
| 2026-09-26 00:00 |
06:30:40.28 |
+54:01:17.5 |
HIP 31080 |
15.86 |
| 2026-09-26 12:00 |
06:30:40.58 |
+54:01:39.6 |
HIP 31080 |
16.19 |
| 2026-09-27 00:00 |
06:30:40.82 |
+54:02:01.8 |
HIP 31080 |
16.53 |
| 2026-09-27 12:00 |
06:30:41.02 |
+54:02:24.0 |
HIP 31080 |
16.86 |
| 2026-09-28 00:00 |
06:30:41.18 |
+54:02:46.2 |
HIP 31080 |
17.21 |
| 2026-09-28 12:00 |
06:30:41.29 |
+54:03:08.5 |
HIP 31080 |
17.55 |
| 2026-09-29 00:00 |
06:30:41.35 |
+54:03:30.8 |
HIP 31080 |
17.90 |
| 2026-09-29 12:00 |
06:30:41.37 |
+54:03:53.1 |
HIP 31080 |
18.25 |
| 2026-09-30 00:00 |
06:30:41.34 |
+54:04:15.5 |
HIP 31080 |
18.61 |
| 2026-09-30 12:00 |
06:30:41.27 |
+54:04:37.8 |
HIP 31080 |
18.97 |
| 2026-10-01 00:00 |
06:30:41.15 |
+54:05:00.3 |
HIP 31080 |
19.33 |
| 2026-10-01 12:00 |
06:30:40.99 |
+54:05:22.7 |
HIP 31080 |
19.70 |
| 2026-10-02 00:00 |
06:30:40.78 |
+54:05:45.2 |
HIP 31080 |
20.06 |
| 2026-10-02 12:00 |
06:30:40.52 |
+54:06:07.6 |
HIP 31080 |
20.43 |
| 2026-10-03 00:00 |
06:30:40.21 |
+54:06:30.1 |
HIP 31080 |
20.80 |
| 2026-10-03 12:00 |
06:30:39.87 |
+54:06:52.6 |
HIP 31080 |
21.18 |
| 2026-10-04 00:00 |
06:30:39.47 |
+54:07:15.2 |
HIP 31080 |
21.56 |
| 2026-10-04 12:00 |
06:30:39.03 |
+54:07:37.7 |
HIP 31080 |
21.94 |
| 2026-10-05 00:00 |
06:30:38.54 |
+54:08:00.3 |
HIP 31080 |
22.32 |
| 2026-10-05 12:00 |
06:30:38.00 |
+54:08:22.8 |
HIP 31080 |
22.70 |
| 2026-10-06 00:00 |
06:30:37.42 |
+54:08:45.4 |
HIP 31080 |
23.09 |
| 2026-10-06 12:00 |
06:30:36.79 |
+54:09:08.0 |
HIP 30817 |
23.42 |
| 2026-10-07 00:00 |
06:30:36.12 |
+54:09:30.6 |
HIP 30817 |
23.11 |
| 2026-10-07 12:00 |
06:30:35.40 |
+54:09:53.2 |
HIP 30817 |
22.81 |
| 2026-10-08 00:00 |
06:30:34.63 |
+54:10:15.8 |
HIP 30817 |
22.50 |
| 2026-10-08 12:00 |
06:30:33.81 |
+54:10:38.3 |
HIP 30817 |
22.18 |
| 2026-10-09 00:00 |
06:30:32.95 |
+54:11:00.9 |
HIP 30817 |
21.87 |
| 2026-10-09 12:00 |
06:30:32.04 |
+54:11:23.5 |
HIP 30817 |
21.55 |
| 2026-10-10 00:00 |
06:30:31.09 |
+54:11:46.1 |
HIP 30817 |
21.22 |
| 2026-10-10 12:00 |
06:30:30.08 |
+54:12:08.6 |
HIP 30817 |
20.90 |
| 2026-10-11 00:00 |
06:30:29.03 |
+54:12:31.2 |
HIP 30817 |
20.57 |