メタデータ
| 項目 |
値 |
| Designation |
C/1995 Y1 (Hyakutake) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1996-02-24T06:53:53.528640Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:47Z |
| Obs used |
259 |
| NEO |
- |
| M1 |
9.900 |
| K1 |
15.000 |
| PC |
0.030 |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
1996-02-24.0000000 |
| e |
1.00026947 |
| q (au) |
1.054617 |
| a (au) |
-3913.664483 |
| i (deg) |
54.466072 |
| Ω (om, deg) |
195.761478 |
| ω (w, deg) |
46.348701 |
| M (ma, deg) |
-0.000001 |
等級
散乱 + 全体線形
$$
M_a = (6.861 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
6.861 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.998 |
| 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 |
| 1995-12-27 |
1996-01-15 |
-32.9619 |
+4.433 |
| 1996-01-15 |
1996-02-24 |
+5.8871 |
-0.300 |
| 1996-02-24 |
1996-07-18 |
+2.0313 |
-0.181 |
| 1996-07-18 |
1996-10-05 |
+7.6754 |
-1.742 |
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 |
02:38:31.81 |
-09:34:07.6 |
HIP 12363 |
18.21 |
| 2026-03-26 12:00 |
02:38:33.54 |
-09:33:52.4 |
HIP 12363 |
18.22 |
| 2026-03-27 00:00 |
02:38:35.29 |
-09:33:37.1 |
HIP 12363 |
18.24 |
| 2026-03-27 12:00 |
02:38:37.04 |
-09:33:22.0 |
HIP 12363 |
18.28 |
| 2026-03-28 00:00 |
02:38:38.80 |
-09:33:06.9 |
HIP 12363 |
18.33 |
| 2026-03-28 12:00 |
02:38:40.58 |
-09:32:51.8 |
HIP 12363 |
18.39 |
| 2026-03-29 00:00 |
02:38:42.36 |
-09:32:36.8 |
HIP 12363 |
18.46 |
| 2026-03-29 12:00 |
02:38:44.15 |
-09:32:21.9 |
HIP 12363 |
18.54 |
| 2026-03-30 00:00 |
02:38:45.95 |
-09:32:07.0 |
HIP 12363 |
18.63 |
| 2026-03-30 12:00 |
02:38:47.77 |
-09:31:52.2 |
HIP 12363 |
18.74 |
| 2026-03-31 00:00 |
02:38:49.59 |
-09:31:37.4 |
HIP 12363 |
18.86 |
| 2026-03-31 12:00 |
02:38:51.42 |
-09:31:22.7 |
HIP 12363 |
18.99 |
| 2026-04-01 00:00 |
02:38:53.26 |
-09:31:08.1 |
HIP 12363 |
19.13 |
| 2026-04-01 12:00 |
02:38:55.10 |
-09:30:53.5 |
HIP 12363 |
19.28 |
| 2026-04-02 00:00 |
02:38:56.96 |
-09:30:39.0 |
HIP 12444 |
18.95 |
| 2026-04-02 12:00 |
02:38:58.83 |
-09:30:24.5 |
HIP 12444 |
18.46 |
| 2026-04-03 00:00 |
02:39:00.70 |
-09:30:10.2 |
HIP 12444 |
17.96 |
| 2026-04-03 12:00 |
02:39:02.59 |
-09:29:55.9 |
HIP 12444 |
17.46 |
| 2026-04-04 00:00 |
02:39:04.48 |
-09:29:41.6 |
HIP 12444 |
16.96 |
| 2026-04-04 12:00 |
02:39:06.38 |
-09:29:27.4 |
HIP 12444 |
16.47 |
| 2026-04-05 00:00 |
02:39:08.29 |
-09:29:13.3 |
HIP 12444 |
15.97 |
| 2026-04-05 12:00 |
02:39:10.20 |
-09:28:59.3 |
HIP 12444 |
15.47 |
| 2026-04-06 00:00 |
02:39:12.13 |
-09:28:45.3 |
HIP 12444 |
14.97 |
| 2026-04-06 12:00 |
02:39:14.06 |
-09:28:31.4 |
HIP 12444 |
14.48 |
| 2026-04-07 00:00 |
02:39:16.00 |
-09:28:17.6 |
HIP 12444 |
13.98 |
| 2026-04-07 12:00 |
02:39:17.94 |
-09:28:03.9 |
HIP 12444 |
13.48 |
| 2026-04-08 00:00 |
02:39:19.90 |
-09:27:50.2 |
HIP 12444 |
12.99 |
| 2026-04-08 12:00 |
02:39:21.86 |
-09:27:36.6 |
HIP 12444 |
12.50 |
| 2026-04-09 00:00 |
02:39:23.83 |
-09:27:23.1 |
HIP 12444 |
12.01 |
| 2026-04-09 12:00 |
02:39:25.80 |
-09:27:09.7 |
HIP 12444 |
11.52 |
| 2026-04-10 00:00 |
02:39:27.78 |
-09:26:56.3 |
HIP 12444 |
11.03 |
| 2026-04-10 12:00 |
02:39:29.77 |
-09:26:43.0 |
HIP 12444 |
10.55 |
| 2026-04-11 00:00 |
02:39:31.77 |
-09:26:29.9 |
HIP 12444 |
10.07 |
| 2026-04-11 12:00 |
02:39:33.77 |
-09:26:16.7 |
HIP 12444 |
9.59 |
| 2026-04-12 00:00 |
02:39:35.78 |
-09:26:03.7 |
HIP 12444 |
9.12 |
| 2026-04-12 12:00 |
02:39:37.79 |
-09:25:50.8 |
HIP 12444 |
8.66 |
| 2026-04-13 00:00 |
02:39:39.81 |
-09:25:37.9 |
HIP 12444 |
8.21 |
| 2026-04-13 12:00 |
02:39:41.84 |
-09:25:25.1 |
HIP 12444 |
7.76 |
| 2026-04-14 00:00 |
02:39:43.87 |
-09:25:12.4 |
HIP 12444 |
7.33 |
| 2026-04-14 12:00 |
02:39:45.91 |
-09:24:59.8 |
HIP 12444 |
6.91 |
| 2026-04-15 00:00 |
02:39:47.95 |
-09:24:47.3 |
HIP 12444 |
6.50 |
| 2026-04-15 12:00 |
02:39:50.00 |
-09:24:34.9 |
HIP 12444 |
6.12 |
| 2026-04-16 00:00 |
02:39:52.05 |
-09:24:22.6 |
HIP 12444 |
5.76 |