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 |
-9.7164 |
+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) |
| 2026-03-26 00:00 |
02:49:20.93 |
+51:36:29.8 |
HIP 13097 |
9.63 |
| 2026-03-26 12:00 |
02:49:23.60 |
+51:36:22.6 |
HIP 13097 |
9.97 |
| 2026-03-27 00:00 |
02:49:26.28 |
+51:36:15.5 |
HIP 13097 |
10.31 |
| 2026-03-27 12:00 |
02:49:28.99 |
+51:36:08.7 |
HIP 13097 |
10.67 |
| 2026-03-28 00:00 |
02:49:31.71 |
+51:36:02.0 |
HIP 13097 |
11.03 |
| 2026-03-28 12:00 |
02:49:34.45 |
+51:35:55.5 |
HIP 13097 |
11.41 |
| 2026-03-29 00:00 |
02:49:37.21 |
+51:35:49.2 |
HIP 13097 |
11.79 |
| 2026-03-29 12:00 |
02:49:39.99 |
+51:35:43.0 |
HIP 13097 |
12.18 |
| 2026-03-30 00:00 |
02:49:42.79 |
+51:35:37.1 |
HIP 13097 |
12.58 |
| 2026-03-30 12:00 |
02:49:45.60 |
+51:35:31.3 |
HIP 13097 |
12.98 |
| 2026-03-31 00:00 |
02:49:48.43 |
+51:35:25.7 |
HIP 13097 |
13.39 |
| 2026-03-31 12:00 |
02:49:51.27 |
+51:35:20.3 |
HIP 13097 |
13.80 |
| 2026-04-01 00:00 |
02:49:54.13 |
+51:35:15.1 |
HIP 13097 |
14.22 |
| 2026-04-01 12:00 |
02:49:57.01 |
+51:35:10.0 |
HIP 13097 |
14.65 |
| 2026-04-02 00:00 |
02:49:59.91 |
+51:35:05.2 |
HIP 13097 |
15.08 |
| 2026-04-02 12:00 |
02:50:02.82 |
+51:35:00.5 |
HIP 13097 |
15.51 |
| 2026-04-03 00:00 |
02:50:05.74 |
+51:34:56.0 |
HIP 13097 |
15.95 |
| 2026-04-03 12:00 |
02:50:08.69 |
+51:34:51.7 |
HIP 13097 |
16.39 |
| 2026-04-04 00:00 |
02:50:11.64 |
+51:34:47.6 |
HIP 13097 |
16.84 |
| 2026-04-04 12:00 |
02:50:14.62 |
+51:34:43.6 |
HIP 13097 |
17.29 |
| 2026-04-05 00:00 |
02:50:17.60 |
+51:34:39.9 |
HIP 13097 |
17.74 |
| 2026-04-05 12:00 |
02:50:20.60 |
+51:34:36.3 |
HIP 13097 |
18.20 |
| 2026-04-06 00:00 |
02:50:23.62 |
+51:34:32.9 |
HIP 13097 |
18.66 |
| 2026-04-06 12:00 |
02:50:26.65 |
+51:34:29.7 |
HIP 13097 |
19.12 |
| 2026-04-07 00:00 |
02:50:29.70 |
+51:34:26.6 |
HIP 13097 |
19.59 |
| 2026-04-07 12:00 |
02:50:32.76 |
+51:34:23.8 |
HIP 13097 |
20.06 |
| 2026-04-08 00:00 |
02:50:35.83 |
+51:34:21.1 |
HIP 13097 |
20.53 |
| 2026-04-08 12:00 |
02:50:38.91 |
+51:34:18.6 |
HIP 13097 |
21.00 |
| 2026-04-09 00:00 |
02:50:42.01 |
+51:34:16.3 |
HIP 13097 |
21.48 |
| 2026-04-09 12:00 |
02:50:45.12 |
+51:34:14.2 |
HIP 13097 |
21.96 |
| 2026-04-10 00:00 |
02:50:48.25 |
+51:34:12.3 |
HIP 13097 |
22.44 |
| 2026-04-10 12:00 |
02:50:51.39 |
+51:34:10.5 |
HIP 13097 |
22.93 |
| 2026-04-11 00:00 |
02:50:54.54 |
+51:34:08.9 |
HIP 13097 |
23.41 |
| 2026-04-11 12:00 |
02:50:57.70 |
+51:34:07.6 |
HIP 13097 |
23.90 |
| 2026-04-12 00:00 |
02:51:00.87 |
+51:34:06.3 |
HIP 13097 |
24.39 |
| 2026-04-12 12:00 |
02:51:04.06 |
+51:34:05.3 |
HIP 13097 |
24.89 |
| 2026-04-13 00:00 |
02:51:07.25 |
+51:34:04.5 |
HIP 13097 |
25.38 |
| 2026-04-13 12:00 |
02:51:10.46 |
+51:34:03.8 |
HIP 13097 |
25.88 |
| 2026-04-14 00:00 |
02:51:13.68 |
+51:34:03.4 |
HIP 13097 |
26.38 |
| 2026-04-14 12:00 |
02:51:16.91 |
+51:34:03.1 |
HIP 13097 |
26.88 |
| 2026-04-15 00:00 |
02:51:20.15 |
+51:34:03.0 |
HIP 13097 |
27.38 |
| 2026-04-15 12:00 |
02:51:23.40 |
+51:34:03.0 |
HIP 13097 |
27.89 |
| 2026-04-16 00:00 |
02:51:26.66 |
+51:34:03.3 |
HIP 13097 |
28.39 |