メタデータ
| 項目 |
値 |
| Designation |
C/1987 U3 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1987-12-11T22:32:44.332800Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:36Z |
| Obs used |
106 |
| NEO |
- |
| M1 |
6.100 |
| K1 |
17.250 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
1988-01-08.0000000 |
| e |
0.99855807 |
| q (au) |
0.841167 |
| a (au) |
583.363126 |
| i (deg) |
97.126481 |
| Ω (om, deg) |
261.341785 |
| ω (w, deg) |
17.409142 |
| M (ma, deg) |
0.001893 |
等級
散乱 + 全体線形
$$
M_a = (4.978 + 3.538\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
4.978 |
| n |
3.538 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
1.000 |
| 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 |
| 1987-12-27 |
1988-02-01 |
-7.4131 |
+0.143 |
| 1988-02-01 |
1988-02-18 |
+3.8294 |
-0.662 |
| 1988-02-18 |
1988-03-22 |
+3.4165 |
-0.549 |
| 1988-03-22 |
1988-05-10 |
-6.7830 |
+2.088 |
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 |
05:17:13.31 |
+18:34:05.8 |
HIP 24612 |
10.41 |
| 2026-03-26 12:00 |
05:17:13.80 |
+18:34:07.9 |
HIP 24612 |
10.51 |
| 2026-03-27 00:00 |
05:17:14.31 |
+18:34:10.0 |
HIP 24612 |
10.62 |
| 2026-03-27 12:00 |
05:17:14.84 |
+18:34:12.1 |
HIP 24612 |
10.73 |
| 2026-03-28 00:00 |
05:17:15.38 |
+18:34:14.3 |
HIP 24612 |
10.85 |
| 2026-03-28 12:00 |
05:17:15.94 |
+18:34:16.4 |
HIP 24612 |
10.96 |
| 2026-03-29 00:00 |
05:17:16.51 |
+18:34:18.5 |
HIP 24612 |
11.08 |
| 2026-03-29 12:00 |
05:17:17.10 |
+18:34:20.7 |
HIP 24612 |
11.21 |
| 2026-03-30 00:00 |
05:17:17.71 |
+18:34:22.9 |
HIP 24612 |
11.33 |
| 2026-03-30 12:00 |
05:17:18.33 |
+18:34:25.1 |
HIP 24612 |
11.46 |
| 2026-03-31 00:00 |
05:17:18.97 |
+18:34:27.2 |
HIP 24612 |
11.60 |
| 2026-03-31 12:00 |
05:17:19.62 |
+18:34:29.4 |
HIP 24612 |
11.73 |
| 2026-04-01 00:00 |
05:17:20.29 |
+18:34:31.6 |
HIP 24612 |
11.88 |
| 2026-04-01 12:00 |
05:17:20.98 |
+18:34:33.9 |
HIP 24612 |
12.02 |
| 2026-04-02 00:00 |
05:17:21.68 |
+18:34:36.1 |
HIP 24612 |
12.17 |
| 2026-04-02 12:00 |
05:17:22.40 |
+18:34:38.3 |
HIP 24612 |
12.32 |
| 2026-04-03 00:00 |
05:17:23.13 |
+18:34:40.6 |
HIP 24612 |
12.47 |
| 2026-04-03 12:00 |
05:17:23.88 |
+18:34:42.8 |
HIP 24612 |
12.63 |
| 2026-04-04 00:00 |
05:17:24.64 |
+18:34:45.1 |
HIP 24612 |
12.79 |
| 2026-04-04 12:00 |
05:17:25.42 |
+18:34:47.3 |
HIP 24612 |
12.95 |
| 2026-04-05 00:00 |
05:17:26.22 |
+18:34:49.6 |
HIP 24612 |
13.12 |
| 2026-04-05 12:00 |
05:17:27.03 |
+18:34:51.9 |
HIP 24612 |
13.29 |
| 2026-04-06 00:00 |
05:17:27.85 |
+18:34:54.2 |
HIP 24612 |
13.47 |
| 2026-04-06 12:00 |
05:17:28.69 |
+18:34:56.5 |
HIP 24612 |
13.65 |
| 2026-04-07 00:00 |
05:17:29.55 |
+18:34:58.8 |
HIP 24612 |
13.83 |
| 2026-04-07 12:00 |
05:17:30.42 |
+18:35:01.1 |
HIP 24612 |
14.02 |
| 2026-04-08 00:00 |
05:17:31.30 |
+18:35:03.4 |
HIP 24612 |
14.21 |
| 2026-04-08 12:00 |
05:17:32.20 |
+18:35:05.8 |
HIP 24612 |
14.40 |
| 2026-04-09 00:00 |
05:17:33.12 |
+18:35:08.1 |
HIP 24612 |
14.60 |
| 2026-04-09 12:00 |
05:17:34.05 |
+18:35:10.4 |
HIP 24612 |
14.80 |
| 2026-04-10 00:00 |
05:17:34.99 |
+18:35:12.8 |
HIP 24612 |
15.00 |
| 2026-04-10 12:00 |
05:17:35.95 |
+18:35:15.1 |
HIP 24612 |
15.21 |
| 2026-04-11 00:00 |
05:17:36.93 |
+18:35:17.5 |
HIP 24612 |
15.42 |
| 2026-04-11 12:00 |
05:17:37.91 |
+18:35:19.8 |
HIP 24612 |
15.63 |
| 2026-04-12 00:00 |
05:17:38.92 |
+18:35:22.2 |
HIP 24612 |
15.85 |
| 2026-04-12 12:00 |
05:17:39.93 |
+18:35:24.5 |
HIP 24612 |
16.07 |
| 2026-04-13 00:00 |
05:17:40.96 |
+18:35:26.9 |
HIP 24612 |
16.29 |
| 2026-04-13 12:00 |
05:17:42.01 |
+18:35:29.3 |
HIP 24612 |
16.52 |
| 2026-04-14 00:00 |
05:17:43.07 |
+18:35:31.7 |
HIP 24612 |
16.75 |
| 2026-04-14 12:00 |
05:17:44.14 |
+18:35:34.0 |
HIP 24612 |
16.99 |
| 2026-04-15 00:00 |
05:17:45.23 |
+18:35:36.4 |
HIP 24612 |
17.23 |
| 2026-04-15 12:00 |
05:17:46.33 |
+18:35:38.8 |
HIP 24612 |
17.47 |
| 2026-04-16 00:00 |
05:17:47.44 |
+18:35:41.2 |
HIP 24612 |
17.71 |