メタデータ
| 項目 |
値 |
| Designation |
C/1991 L4 (Helin-Alu) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1992-02-19T22:39:07.948800Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:41Z |
| Obs used |
80 |
| NEO |
- |
| M1 |
10.100 |
| 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) |
1992-06-10.0000000 |
| e |
1.00017877 |
| q (au) |
4.849875 |
| a (au) |
-27129.680481 |
| i (deg) |
49.292514 |
| Ω (om, deg) |
253.650707 |
| ω (w, deg) |
30.794475 |
| M (ma, deg) |
0.000024 |
等級
散乱 + 全体線形
$$
M_a = (0.872 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
0.872 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| 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
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
04:41:32.08 |
+25:02:22.2 |
HIP 21759 |
16.11 |
| 2026-09-20 12:00 |
04:41:31.53 |
+25:02:21.3 |
HIP 21759 |
15.99 |
| 2026-09-21 00:00 |
04:41:30.96 |
+25:02:20.4 |
HIP 21759 |
15.86 |
| 2026-09-21 12:00 |
04:41:30.37 |
+25:02:19.5 |
HIP 21759 |
15.73 |
| 2026-09-22 00:00 |
04:41:29.76 |
+25:02:18.5 |
HIP 21759 |
15.59 |
| 2026-09-22 12:00 |
04:41:29.13 |
+25:02:17.5 |
HIP 21759 |
15.45 |
| 2026-09-23 00:00 |
04:41:28.48 |
+25:02:16.4 |
HIP 21759 |
15.30 |
| 2026-09-23 12:00 |
04:41:27.81 |
+25:02:15.3 |
HIP 21759 |
15.15 |
| 2026-09-24 00:00 |
04:41:27.12 |
+25:02:14.1 |
HIP 21759 |
15.00 |
| 2026-09-24 12:00 |
04:41:26.42 |
+25:02:12.9 |
HIP 21759 |
14.84 |
| 2026-09-25 00:00 |
04:41:25.69 |
+25:02:11.7 |
HIP 21759 |
14.68 |
| 2026-09-25 12:00 |
04:41:24.95 |
+25:02:10.4 |
HIP 21759 |
14.51 |
| 2026-09-26 00:00 |
04:41:24.19 |
+25:02:09.1 |
HIP 21759 |
14.34 |
| 2026-09-26 12:00 |
04:41:23.41 |
+25:02:07.8 |
HIP 21759 |
14.17 |
| 2026-09-27 00:00 |
04:41:22.61 |
+25:02:06.4 |
HIP 21759 |
13.99 |
| 2026-09-27 12:00 |
04:41:21.79 |
+25:02:05.0 |
HIP 21759 |
13.80 |
| 2026-09-28 00:00 |
04:41:20.95 |
+25:02:03.5 |
HIP 21759 |
13.62 |
| 2026-09-28 12:00 |
04:41:20.09 |
+25:02:02.0 |
HIP 21759 |
13.43 |
| 2026-09-29 00:00 |
04:41:19.22 |
+25:02:00.4 |
HIP 21759 |
13.23 |
| 2026-09-29 12:00 |
04:41:18.32 |
+25:01:58.8 |
HIP 21759 |
13.03 |
| 2026-09-30 00:00 |
04:41:17.41 |
+25:01:57.2 |
HIP 21759 |
12.83 |
| 2026-09-30 12:00 |
04:41:16.48 |
+25:01:55.5 |
HIP 21759 |
12.62 |
| 2026-10-01 00:00 |
04:41:15.53 |
+25:01:53.8 |
HIP 21759 |
12.41 |
| 2026-10-01 12:00 |
04:41:14.56 |
+25:01:52.1 |
HIP 21759 |
12.19 |
| 2026-10-02 00:00 |
04:41:13.58 |
+25:01:50.3 |
HIP 21759 |
11.97 |
| 2026-10-02 12:00 |
04:41:12.57 |
+25:01:48.5 |
HIP 21759 |
11.75 |
| 2026-10-03 00:00 |
04:41:11.55 |
+25:01:46.6 |
HIP 21759 |
11.53 |
| 2026-10-03 12:00 |
04:41:10.51 |
+25:01:44.7 |
HIP 21759 |
11.30 |
| 2026-10-04 00:00 |
04:41:09.45 |
+25:01:42.7 |
HIP 21759 |
11.06 |
| 2026-10-04 12:00 |
04:41:08.37 |
+25:01:40.7 |
HIP 21759 |
10.82 |
| 2026-10-05 00:00 |
04:41:07.28 |
+25:01:38.7 |
HIP 21759 |
10.58 |
| 2026-10-05 12:00 |
04:41:06.16 |
+25:01:36.6 |
HIP 21759 |
10.34 |
| 2026-10-06 00:00 |
04:41:05.03 |
+25:01:34.5 |
HIP 21759 |
10.09 |
| 2026-10-06 12:00 |
04:41:03.88 |
+25:01:32.4 |
HIP 21759 |
9.84 |
| 2026-10-07 00:00 |
04:41:02.72 |
+25:01:30.2 |
HIP 21759 |
9.58 |
| 2026-10-07 12:00 |
04:41:01.53 |
+25:01:28.0 |
HIP 21759 |
9.33 |
| 2026-10-08 00:00 |
04:41:00.33 |
+25:01:25.7 |
HIP 21759 |
9.07 |
| 2026-10-08 12:00 |
04:40:59.11 |
+25:01:23.4 |
HIP 21759 |
8.80 |
| 2026-10-09 00:00 |
04:40:57.87 |
+25:01:21.0 |
HIP 21759 |
8.54 |
| 2026-10-09 12:00 |
04:40:56.62 |
+25:01:18.6 |
HIP 21759 |
8.27 |
| 2026-10-10 00:00 |
04:40:55.35 |
+25:01:16.2 |
HIP 21759 |
8.00 |
| 2026-10-10 12:00 |
04:40:54.06 |
+25:01:13.7 |
HIP 21759 |
7.72 |
| 2026-10-11 00:00 |
04:40:52.76 |
+25:01:11.2 |
HIP 21759 |
7.45 |