メタデータ
| 項目 |
値 |
| Designation |
132P/Helin-Roman-Alu 2 |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2021-11-13T02:33:18.385920Z |
| Orbit solution date (soln_date, UTC) |
2025-11-23T22:26:53Z |
| Obs used |
1323 |
| NEO |
- |
| M1 |
10.200 |
| K1 |
22.250 |
| PC |
0.030 |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2021-10-04.0000000 |
| e |
0.56469630 |
| q (au) |
1.691775 |
| a (au) |
3.886424 |
| i (deg) |
5.382515 |
| Ω (om, deg) |
173.996571 |
| ω (w, deg) |
216.345515 |
| M (ma, deg) |
354.840671 |
等級
散乱 + 全体線形
$$
M_a = (11.038 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
11.038 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| 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 |
| 2021-06-12 |
2021-08-13 |
-0.6116 |
+1.350 |
| 2021-08-13 |
2021-11-12 |
+29.4087 |
-7.185 |
| 2021-11-14 |
2022-04-02 |
-6.8747 |
+1.167 |
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 |
14:54:51.89 |
-12:06:44.6 |
HIP 72934 |
14.67 |
| 2026-03-26 12:00 |
14:54:41.49 |
-12:05:35.2 |
HIP 72934 |
12.54 |
| 2026-03-27 00:00 |
14:54:30.95 |
-12:04:25.2 |
HIP 72934 |
10.70 |
| 2026-03-27 12:00 |
14:54:20.26 |
-12:03:14.7 |
HIP 72934 |
9.37 |
| 2026-03-28 00:00 |
14:54:09.43 |
-12:02:03.7 |
HIP 72934 |
8.80 |
| 2026-03-28 12:00 |
14:53:58.46 |
-12:00:52.1 |
HIP 72934 |
9.18 |
| 2026-03-29 00:00 |
14:53:47.35 |
-11:59:40.1 |
HIP 72934 |
10.44 |
| 2026-03-29 12:00 |
14:53:36.10 |
-11:58:27.5 |
HIP 72934 |
12.32 |
| 2026-03-30 00:00 |
14:53:24.71 |
-11:57:14.4 |
HIP 72934 |
14.62 |
| 2026-03-30 12:00 |
14:53:13.19 |
-11:56:00.8 |
HIP 72934 |
17.18 |
| 2026-03-31 00:00 |
14:53:01.53 |
-11:54:46.7 |
HIP 72934 |
19.93 |
| 2026-03-31 12:00 |
14:52:49.74 |
-11:53:32.2 |
HIP 72934 |
22.80 |
| 2026-04-01 00:00 |
14:52:37.81 |
-11:52:17.1 |
HIP 72750 |
24.26 |
| 2026-04-01 12:00 |
14:52:25.75 |
-11:51:01.6 |
HIP 72750 |
22.68 |
| 2026-04-02 00:00 |
14:52:13.57 |
-11:49:45.7 |
HIP 72750 |
21.46 |
| 2026-04-02 12:00 |
14:52:01.25 |
-11:48:29.2 |
HIP 72750 |
20.69 |
| 2026-04-03 00:00 |
14:51:48.81 |
-11:47:12.4 |
HIP 72750 |
20.42 |
| 2026-04-03 12:00 |
14:51:36.25 |
-11:45:55.1 |
HIP 72750 |
20.69 |
| 2026-04-04 00:00 |
14:51:23.56 |
-11:44:37.4 |
HIP 72596 |
20.14 |
| 2026-04-04 12:00 |
14:51:10.75 |
-11:43:19.2 |
HIP 72596 |
19.68 |
| 2026-04-05 00:00 |
14:50:57.82 |
-11:42:00.6 |
HIP 72596 |
19.80 |
| 2026-04-05 12:00 |
14:50:44.77 |
-11:40:41.6 |
HIP 72596 |
20.51 |
| 2026-04-06 00:00 |
14:50:31.60 |
-11:39:22.3 |
HIP 72596 |
21.75 |
| 2026-04-06 12:00 |
14:50:18.32 |
-11:38:02.5 |
HIP 72596 |
23.46 |
| 2026-04-07 00:00 |
14:50:04.92 |
-11:36:42.4 |
HIP 72596 |
25.56 |
| 2026-04-07 12:00 |
14:49:51.41 |
-11:35:21.8 |
HIP 72596 |
27.97 |
| 2026-04-08 00:00 |
14:49:37.79 |
-11:34:01.0 |
HIP 72596 |
30.62 |
| 2026-04-08 12:00 |
14:49:24.06 |
-11:32:39.7 |
HIP 72596 |
33.47 |
| 2026-04-09 00:00 |
14:49:10.22 |
-11:31:18.1 |
HIP 72301 |
30.54 |
| 2026-04-09 12:00 |
14:48:56.28 |
-11:29:56.2 |
HIP 72301 |
27.25 |
| 2026-04-10 00:00 |
14:48:42.23 |
-11:28:34.0 |
HIP 72301 |
24.06 |
| 2026-04-10 12:00 |
14:48:28.09 |
-11:27:11.4 |
HIP 72299 |
20.83 |
| 2026-04-11 00:00 |
14:48:13.84 |
-11:25:48.5 |
HIP 72299 |
17.12 |
| 2026-04-11 12:00 |
14:47:59.49 |
-11:24:25.3 |
HIP 72299 |
13.40 |
| 2026-04-12 00:00 |
14:47:45.05 |
-11:23:01.9 |
HIP 72299 |
9.71 |
| 2026-04-12 12:00 |
14:47:30.52 |
-11:21:38.1 |
HIP 72299 |
6.13 |
| 2026-04-13 00:00 |
14:47:15.89 |
-11:20:14.1 |
HIP 72299 |
3.17 |
| 2026-04-13 12:00 |
14:47:01.17 |
-11:18:49.9 |
HIP 72299 |
3.49 |
| 2026-04-14 00:00 |
14:46:46.36 |
-11:17:25.3 |
HIP 72299 |
6.68 |
| 2026-04-14 12:00 |
14:46:31.47 |
-11:16:00.6 |
HIP 72299 |
10.38 |
| 2026-04-15 00:00 |
14:46:16.50 |
-11:14:35.6 |
HIP 72168 |
14.09 |
| 2026-04-15 12:00 |
14:46:01.44 |
-11:13:10.4 |
HIP 72168 |
13.32 |
| 2026-04-16 00:00 |
14:45:46.30 |
-11:11:45.1 |
HIP 72168 |
13.70 |