メタデータ
| 項目 |
値 |
| Designation |
C/1999 S2 (McNaught-Watson) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1997-11-22T14:49:59.252160Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:02Z |
| Obs used |
88 |
| NEO |
- |
| M1 |
8.000 |
| K1 |
4.500 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2000-03-17.0000000 |
| e |
1.00527083 |
| q (au) |
6.467743 |
| a (au) |
-1227.083165 |
| i (deg) |
65.820220 |
| Ω (om, deg) |
74.460976 |
| ω (w, deg) |
223.497414 |
| M (ma, deg) |
0.019384 |
等級
散乱 + 全体線形
$$
M_a = (12.223 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
12.223 |
| n |
2.000 |
| gf |
0.828 |
| gb |
-0.827 |
| k |
0.800 |
| δ90 |
9.796 |
| 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) |
| 2026-05-12 00:00 |
04:49:47.48 |
+22:09:46.9 |
HIP 22443 |
12.80 |
| 2026-05-12 12:00 |
04:49:49.96 |
+22:09:53.7 |
HIP 22443 |
12.95 |
| 2026-05-13 00:00 |
04:49:52.44 |
+22:10:00.6 |
HIP 22443 |
13.12 |
| 2026-05-13 12:00 |
04:49:54.92 |
+22:10:07.4 |
HIP 22443 |
13.31 |
| 2026-05-14 00:00 |
04:49:57.42 |
+22:10:14.3 |
HIP 22443 |
13.52 |
| 2026-05-14 12:00 |
04:49:59.93 |
+22:10:21.1 |
HIP 22443 |
13.76 |
| 2026-05-15 00:00 |
04:50:02.44 |
+22:10:28.0 |
HIP 22443 |
14.02 |
| 2026-05-15 12:00 |
04:50:04.96 |
+22:10:34.9 |
HIP 22443 |
14.30 |
| 2026-05-16 00:00 |
04:50:07.48 |
+22:10:41.8 |
HIP 22443 |
14.60 |
| 2026-05-16 12:00 |
04:50:10.02 |
+22:10:48.7 |
HIP 22443 |
14.92 |
| 2026-05-17 00:00 |
04:50:12.56 |
+22:10:55.6 |
HIP 22443 |
15.25 |
| 2026-05-17 12:00 |
04:50:15.10 |
+22:11:02.5 |
HIP 22443 |
15.61 |
| 2026-05-18 00:00 |
04:50:17.66 |
+22:11:09.5 |
HIP 22443 |
15.97 |
| 2026-05-18 12:00 |
04:50:20.22 |
+22:11:16.4 |
HIP 22443 |
16.36 |
| 2026-05-19 00:00 |
04:50:22.78 |
+22:11:23.3 |
HIP 22443 |
16.75 |
| 2026-05-19 12:00 |
04:50:25.35 |
+22:11:30.2 |
HIP 22443 |
17.16 |
| 2026-05-20 00:00 |
04:50:27.93 |
+22:11:37.2 |
HIP 22443 |
17.58 |
| 2026-05-20 12:00 |
04:50:30.51 |
+22:11:44.1 |
HIP 22443 |
18.02 |
| 2026-05-21 00:00 |
04:50:33.10 |
+22:11:51.1 |
HIP 22443 |
18.46 |
| 2026-05-21 12:00 |
04:50:35.69 |
+22:11:58.0 |
HIP 22443 |
18.91 |
| 2026-05-22 00:00 |
04:50:38.29 |
+22:12:05.0 |
HIP 22443 |
19.38 |
| 2026-05-22 12:00 |
04:50:40.89 |
+22:12:12.0 |
HIP 22443 |
19.85 |
| 2026-05-23 00:00 |
04:50:43.50 |
+22:12:18.9 |
HIP 22443 |
20.33 |
| 2026-05-23 12:00 |
04:50:46.11 |
+22:12:25.9 |
HIP 22443 |
20.82 |
| 2026-05-24 00:00 |
04:50:48.72 |
+22:12:32.8 |
HIP 22443 |
21.31 |
| 2026-05-24 12:00 |
04:50:51.34 |
+22:12:39.8 |
HIP 22443 |
21.82 |
| 2026-05-25 00:00 |
04:50:53.97 |
+22:12:46.8 |
HIP 22443 |
22.32 |
| 2026-05-25 12:00 |
04:50:56.59 |
+22:12:53.8 |
HIP 22443 |
22.84 |
| 2026-05-26 00:00 |
04:50:59.22 |
+22:13:00.7 |
HIP 22443 |
23.36 |
| 2026-05-26 12:00 |
04:51:01.86 |
+22:13:07.7 |
HIP 22443 |
23.89 |
| 2026-05-27 00:00 |
04:51:04.49 |
+22:13:14.7 |
HIP 22443 |
24.42 |
| 2026-05-27 12:00 |
04:51:07.13 |
+22:13:21.7 |
HIP 22443 |
24.95 |
| 2026-05-28 00:00 |
04:51:09.77 |
+22:13:28.6 |
HIP 22443 |
25.49 |
| 2026-05-28 12:00 |
04:51:12.42 |
+22:13:35.6 |
HIP 22715 |
25.97 |
| 2026-05-29 00:00 |
04:51:15.07 |
+22:13:42.6 |
HIP 22715 |
25.36 |
| 2026-05-29 12:00 |
04:51:17.72 |
+22:13:49.6 |
HIP 22715 |
24.74 |
| 2026-05-30 00:00 |
04:51:20.37 |
+22:13:56.5 |
HIP 22715 |
24.13 |
| 2026-05-30 12:00 |
04:51:23.02 |
+22:14:03.5 |
HIP 22715 |
23.51 |
| 2026-05-31 00:00 |
04:51:25.68 |
+22:14:10.5 |
HIP 22715 |
22.90 |
| 2026-05-31 12:00 |
04:51:28.34 |
+22:14:17.5 |
HIP 22715 |
22.28 |
| 2026-06-01 00:00 |
04:51:31.00 |
+22:14:24.4 |
HIP 22715 |
21.67 |
| 2026-06-01 12:00 |
04:51:33.66 |
+22:14:31.4 |
HIP 22715 |
21.06 |
| 2026-06-02 00:00 |
04:51:36.32 |
+22:14:38.4 |
HIP 22715 |
20.44 |