メタデータ
| 項目 |
値 |
| Designation |
C/1998 P1 (Williams) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1998-10-17T20:04:26.601600Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:57Z |
| Obs used |
403 |
| NEO |
- |
| M1 |
7.800 |
| K1 |
14.750 |
| PC |
0.030 |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
1998-12-15.0000000 |
| e |
0.99935941 |
| q (au) |
1.146154 |
| a (au) |
1789.224617 |
| i (deg) |
145.728519 |
| Ω (om, deg) |
156.373092 |
| ω (w, deg) |
294.452932 |
| M (ma, deg) |
0.000757 |
等級
散乱 + 全体線形
$$
M_a = (6.727 + 4.174\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
6.727 |
| n |
4.174 |
| gf |
0.891 |
| gb |
-0.729 |
| k |
0.993 |
| δ90 |
1.273 |
| 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 |
| 1998-08-10 |
1998-08-29 |
+48.4077 |
-7.973 |
| 1998-08-29 |
1998-10-04 |
-9.7163 |
+0.414 |
| 1998-11-14 |
1998-12-30 |
-0.7986 |
+0.004 |
| 1998-12-30 |
1999-01-17 |
-4.5488 |
+1.146 |
| 1999-01-17 |
1999-02-09 |
+3.1416 |
-0.885 |
| 1999-02-09 |
1999-03-04 |
+15.9071 |
-5.048 |
| 1999-03-04 |
1999-04-13 |
-6.4456 |
+2.729 |
| 1999-04-13 |
1999-05-18 |
-16.8421 |
+7.088 |
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) |
| 2026-09-20 00:00 |
02:58:51.31 |
+52:52:55.7 |
HIP 13803 |
9.94 |
| 2026-09-20 12:00 |
02:58:48.75 |
+52:53:05.6 |
HIP 13803 |
9.54 |
| 2026-09-21 00:00 |
02:58:46.16 |
+52:53:15.4 |
HIP 13803 |
9.13 |
| 2026-09-21 12:00 |
02:58:43.54 |
+52:53:25.0 |
HIP 13803 |
8.73 |
| 2026-09-22 00:00 |
02:58:40.90 |
+52:53:34.4 |
HIP 13803 |
8.32 |
| 2026-09-22 12:00 |
02:58:38.24 |
+52:53:43.7 |
HIP 13803 |
7.91 |
| 2026-09-23 00:00 |
02:58:35.55 |
+52:53:52.8 |
HIP 13803 |
7.50 |
| 2026-09-23 12:00 |
02:58:32.84 |
+52:54:01.7 |
HIP 13803 |
7.09 |
| 2026-09-24 00:00 |
02:58:30.10 |
+52:54:10.5 |
HIP 13803 |
6.67 |
| 2026-09-24 12:00 |
02:58:27.34 |
+52:54:19.0 |
HIP 13803 |
6.26 |
| 2026-09-25 00:00 |
02:58:24.55 |
+52:54:27.4 |
HIP 13803 |
5.85 |
| 2026-09-25 12:00 |
02:58:21.75 |
+52:54:35.6 |
HIP 13803 |
5.44 |
| 2026-09-26 00:00 |
02:58:18.91 |
+52:54:43.7 |
HIP 13803 |
5.03 |
| 2026-09-26 12:00 |
02:58:16.06 |
+52:54:51.5 |
HIP 13803 |
4.62 |
| 2026-09-27 00:00 |
02:58:13.18 |
+52:54:59.2 |
HIP 13803 |
4.22 |
| 2026-09-27 12:00 |
02:58:10.28 |
+52:55:06.7 |
HIP 13803 |
3.83 |
| 2026-09-28 00:00 |
02:58:07.36 |
+52:55:14.0 |
HIP 13803 |
3.45 |
| 2026-09-28 12:00 |
02:58:04.41 |
+52:55:21.2 |
HIP 13803 |
3.08 |
| 2026-09-29 00:00 |
02:58:01.44 |
+52:55:28.1 |
HIP 13803 |
2.74 |
| 2026-09-29 12:00 |
02:57:58.45 |
+52:55:34.9 |
HIP 13803 |
2.43 |
| 2026-09-30 00:00 |
02:57:55.44 |
+52:55:41.5 |
HIP 13803 |
2.18 |
| 2026-09-30 12:00 |
02:57:52.41 |
+52:55:47.9 |
HIP 13803 |
2.00 |
| 2026-10-01 00:00 |
02:57:49.35 |
+52:55:54.1 |
HIP 13803 |
1.91 |
| 2026-10-01 12:00 |
02:57:46.27 |
+52:56:00.1 |
HIP 13803 |
1.94 |
| 2026-10-02 00:00 |
02:57:43.18 |
+52:56:06.0 |
HIP 13803 |
2.07 |
| 2026-10-02 12:00 |
02:57:40.06 |
+52:56:11.6 |
HIP 13803 |
2.30 |
| 2026-10-03 00:00 |
02:57:36.92 |
+52:56:17.1 |
HIP 13803 |
2.60 |
| 2026-10-03 12:00 |
02:57:33.76 |
+52:56:22.4 |
HIP 13803 |
2.94 |
| 2026-10-04 00:00 |
02:57:30.58 |
+52:56:27.4 |
HIP 13803 |
3.32 |
| 2026-10-04 12:00 |
02:57:27.38 |
+52:56:32.3 |
HIP 13803 |
3.72 |
| 2026-10-05 00:00 |
02:57:24.16 |
+52:56:37.0 |
HIP 13803 |
4.15 |
| 2026-10-05 12:00 |
02:57:20.92 |
+52:56:41.5 |
HIP 13803 |
4.59 |
| 2026-10-06 00:00 |
02:57:17.66 |
+52:56:45.9 |
HIP 13803 |
5.03 |
| 2026-10-06 12:00 |
02:57:14.38 |
+52:56:50.0 |
HIP 13803 |
5.49 |
| 2026-10-07 00:00 |
02:57:11.08 |
+52:56:53.9 |
HIP 13803 |
5.96 |
| 2026-10-07 12:00 |
02:57:07.76 |
+52:56:57.6 |
HIP 13803 |
6.43 |
| 2026-10-08 00:00 |
02:57:04.43 |
+52:57:01.2 |
HIP 13803 |
6.91 |
| 2026-10-08 12:00 |
02:57:01.08 |
+52:57:04.5 |
HIP 13803 |
7.39 |
| 2026-10-09 00:00 |
02:56:57.70 |
+52:57:07.6 |
HIP 13803 |
7.88 |
| 2026-10-09 12:00 |
02:56:54.32 |
+52:57:10.6 |
HIP 13803 |
8.37 |
| 2026-10-10 00:00 |
02:56:50.91 |
+52:57:13.3 |
HIP 13803 |
8.86 |
| 2026-10-10 12:00 |
02:56:47.49 |
+52:57:15.9 |
HIP 13803 |
9.36 |
| 2026-10-11 00:00 |
02:56:44.05 |
+52:57:18.2 |
HIP 13803 |
9.86 |