メタデータ
| 項目 |
値 |
| Designation |
C/1987 W2 (Furuyama) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1988-03-03T01:38:49.009920Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:36Z |
| Obs used |
152 |
| NEO |
- |
| M1 |
9.400 |
| 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) |
1988-01-12.0000000 |
| e |
1.00023007 |
| q (au) |
1.679522 |
| a (au) |
-7299.904944 |
| i (deg) |
117.781967 |
| Ω (om, deg) |
250.752559 |
| ω (w, deg) |
233.626815 |
| M (ma, deg) |
-0.000081 |
等級
散乱 + 全体線形
$$
M_a = (4.822 + 5.790\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
4.822 |
| n |
5.790 |
| gf |
0.999 |
| gb |
-0.950 |
| k |
1.000 |
| δ90 |
9.999 |
| 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) |
| 2026-09-20 00:00 |
15:48:37.40 |
+10:48:31.5 |
HIP 77340 |
26.97 |
| 2026-09-20 12:00 |
15:48:38.27 |
+10:48:17.2 |
HIP 77340 |
26.96 |
| 2026-09-21 00:00 |
15:48:39.16 |
+10:48:02.9 |
HIP 77340 |
26.94 |
| 2026-09-21 12:00 |
15:48:40.06 |
+10:47:48.6 |
HIP 77340 |
26.94 |
| 2026-09-22 00:00 |
15:48:40.97 |
+10:47:34.4 |
HIP 77340 |
26.94 |
| 2026-09-22 12:00 |
15:48:41.90 |
+10:47:20.2 |
HIP 77340 |
26.95 |
| 2026-09-23 00:00 |
15:48:42.84 |
+10:47:06.0 |
HIP 77340 |
26.97 |
| 2026-09-23 12:00 |
15:48:43.79 |
+10:46:51.8 |
HIP 77340 |
26.99 |
| 2026-09-24 00:00 |
15:48:44.76 |
+10:46:37.7 |
HIP 77340 |
27.02 |
| 2026-09-24 12:00 |
15:48:45.74 |
+10:46:23.6 |
HIP 77340 |
27.05 |
| 2026-09-25 00:00 |
15:48:46.74 |
+10:46:09.5 |
HIP 77340 |
27.10 |
| 2026-09-25 12:00 |
15:48:47.75 |
+10:45:55.5 |
HIP 77340 |
27.15 |
| 2026-09-26 00:00 |
15:48:48.77 |
+10:45:41.5 |
HIP 77340 |
27.21 |
| 2026-09-26 12:00 |
15:48:49.80 |
+10:45:27.5 |
HIP 77340 |
27.27 |
| 2026-09-27 00:00 |
15:48:50.85 |
+10:45:13.5 |
HIP 77340 |
27.34 |
| 2026-09-27 12:00 |
15:48:51.91 |
+10:44:59.6 |
HIP 77340 |
27.42 |
| 2026-09-28 00:00 |
15:48:52.98 |
+10:44:45.7 |
HIP 77340 |
27.51 |
| 2026-09-28 12:00 |
15:48:54.06 |
+10:44:31.9 |
HIP 77340 |
27.60 |
| 2026-09-29 00:00 |
15:48:55.16 |
+10:44:18.1 |
HIP 77340 |
27.70 |
| 2026-09-29 12:00 |
15:48:56.27 |
+10:44:04.3 |
HIP 77340 |
27.81 |
| 2026-09-30 00:00 |
15:48:57.39 |
+10:43:50.6 |
HIP 77340 |
27.92 |
| 2026-09-30 12:00 |
15:48:58.53 |
+10:43:36.9 |
HIP 77340 |
28.04 |
| 2026-10-01 00:00 |
15:48:59.68 |
+10:43:23.3 |
HIP 77340 |
28.17 |
| 2026-10-01 12:00 |
15:49:00.84 |
+10:43:09.7 |
HIP 77340 |
28.31 |
| 2026-10-02 00:00 |
15:49:02.01 |
+10:42:56.2 |
HIP 77340 |
28.45 |
| 2026-10-02 12:00 |
15:49:03.19 |
+10:42:42.6 |
HIP 77340 |
28.60 |
| 2026-10-03 00:00 |
15:49:04.39 |
+10:42:29.2 |
HIP 77340 |
28.76 |
| 2026-10-03 12:00 |
15:49:05.60 |
+10:42:15.8 |
HIP 77340 |
28.92 |
| 2026-10-04 00:00 |
15:49:06.82 |
+10:42:02.4 |
HIP 77340 |
29.09 |
| 2026-10-04 12:00 |
15:49:08.05 |
+10:41:49.1 |
HIP 77340 |
29.27 |
| 2026-10-05 00:00 |
15:49:09.29 |
+10:41:35.8 |
HIP 77340 |
29.45 |
| 2026-10-05 12:00 |
15:49:10.55 |
+10:41:22.6 |
HIP 77340 |
29.64 |
| 2026-10-06 00:00 |
15:49:11.82 |
+10:41:09.4 |
HIP 77340 |
29.84 |
| 2026-10-06 12:00 |
15:49:13.10 |
+10:40:56.3 |
HIP 77340 |
30.04 |
| 2026-10-07 00:00 |
15:49:14.39 |
+10:40:43.2 |
HIP 77340 |
30.25 |
| 2026-10-07 12:00 |
15:49:15.69 |
+10:40:30.2 |
HIP 77340 |
30.47 |
| 2026-10-08 00:00 |
15:49:17.00 |
+10:40:17.3 |
HIP 77340 |
30.69 |
| 2026-10-08 12:00 |
15:49:18.33 |
+10:40:04.4 |
HIP 77340 |
30.92 |
| 2026-10-09 00:00 |
15:49:19.66 |
+10:39:51.6 |
HIP 77340 |
31.15 |
| 2026-10-09 12:00 |
15:49:21.01 |
+10:39:38.8 |
HIP 77667 |
31.26 |
| 2026-10-10 00:00 |
15:49:22.36 |
+10:39:26.1 |
HIP 77667 |
30.88 |
| 2026-10-10 12:00 |
15:49:23.73 |
+10:39:13.4 |
HIP 77667 |
30.51 |
| 2026-10-11 00:00 |
15:49:25.11 |
+10:39:00.8 |
HIP 77667 |
30.13 |