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 |
0.998 |
| 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) |
| 2026-09-20 00:00 |
14:35:35.27 |
-11:11:25.2 |
HIP 71375 |
13.09 |
| 2026-09-20 12:00 |
14:35:52.92 |
-11:12:57.9 |
HIP 71375 |
11.34 |
| 2026-09-21 00:00 |
14:36:10.66 |
-11:14:30.7 |
HIP 71375 |
11.32 |
| 2026-09-21 12:00 |
14:36:28.48 |
-11:16:03.7 |
HIP 71375 |
13.06 |
| 2026-09-22 00:00 |
14:36:46.38 |
-11:17:36.9 |
HIP 71375 |
16.02 |
| 2026-09-22 12:00 |
14:37:04.36 |
-11:19:10.2 |
HIP 71375 |
19.66 |
| 2026-09-23 00:00 |
14:37:22.42 |
-11:20:43.7 |
HIP 71451 |
20.31 |
| 2026-09-23 12:00 |
14:37:40.56 |
-11:22:17.4 |
HIP 71451 |
21.56 |
| 2026-09-24 00:00 |
14:37:58.78 |
-11:23:51.2 |
HIP 71646 |
22.32 |
| 2026-09-24 12:00 |
14:38:17.07 |
-11:25:25.2 |
HIP 71646 |
17.71 |
| 2026-09-25 00:00 |
14:38:35.44 |
-11:26:59.3 |
HIP 71646 |
13.20 |
| 2026-09-25 12:00 |
14:38:53.89 |
-11:28:33.6 |
HIP 71646 |
8.95 |
| 2026-09-26 00:00 |
14:39:12.42 |
-11:30:08.0 |
HIP 71646 |
5.61 |
| 2026-09-26 12:00 |
14:39:31.02 |
-11:31:42.5 |
HIP 71646 |
5.41 |
| 2026-09-27 00:00 |
14:39:49.69 |
-11:33:17.2 |
HIP 71646 |
8.58 |
| 2026-09-27 12:00 |
14:40:08.44 |
-11:34:51.9 |
HIP 71646 |
12.86 |
| 2026-09-28 00:00 |
14:40:27.26 |
-11:36:26.8 |
HIP 71646 |
17.46 |
| 2026-09-28 12:00 |
14:40:46.16 |
-11:38:01.9 |
HIP 71808 |
18.07 |
| 2026-09-29 00:00 |
14:41:05.13 |
-11:39:37.0 |
HIP 71808 |
18.08 |
| 2026-09-29 12:00 |
14:41:24.17 |
-11:41:12.2 |
HIP 71808 |
19.39 |
| 2026-09-30 00:00 |
14:41:43.28 |
-11:42:47.6 |
HIP 71808 |
21.76 |
| 2026-09-30 12:00 |
14:42:02.46 |
-11:44:23.0 |
HIP 71808 |
24.92 |
| 2026-10-01 00:00 |
14:42:21.72 |
-11:45:58.5 |
HIP 72023 |
24.07 |
| 2026-10-01 12:00 |
14:42:41.04 |
-11:47:34.2 |
HIP 72023 |
19.09 |
| 2026-10-02 00:00 |
14:43:00.43 |
-11:49:09.9 |
HIP 72023 |
14.10 |
| 2026-10-02 12:00 |
14:43:19.89 |
-11:50:45.7 |
HIP 72023 |
9.10 |
| 2026-10-03 00:00 |
14:43:39.42 |
-11:52:21.6 |
HIP 72023 |
4.17 |
| 2026-10-03 12:00 |
14:43:59.02 |
-11:53:57.5 |
HIP 72023 |
1.62 |
| 2026-10-04 00:00 |
14:44:18.69 |
-11:55:33.5 |
HIP 72023 |
6.26 |
| 2026-10-04 12:00 |
14:44:38.42 |
-11:57:09.6 |
HIP 72023 |
11.29 |
| 2026-10-05 00:00 |
14:44:58.22 |
-11:58:45.8 |
HIP 72023 |
16.37 |
| 2026-10-05 12:00 |
14:45:18.08 |
-12:00:22.0 |
HIP 72023 |
21.47 |
| 2026-10-06 00:00 |
14:45:38.01 |
-12:01:58.2 |
HIP 72174 |
19.31 |
| 2026-10-06 12:00 |
14:45:58.00 |
-12:03:34.5 |
HIP 72174 |
17.95 |
| 2026-10-07 00:00 |
14:46:18.06 |
-12:05:10.9 |
HIP 72174 |
18.02 |
| 2026-10-07 12:00 |
14:46:38.18 |
-12:06:47.3 |
HIP 72174 |
19.51 |
| 2026-10-08 00:00 |
14:46:58.36 |
-12:08:23.7 |
HIP 72174 |
22.15 |
| 2026-10-08 12:00 |
14:47:18.60 |
-12:10:00.1 |
HIP 72174 |
25.59 |
| 2026-10-09 00:00 |
14:47:38.91 |
-12:11:36.6 |
HIP 72174 |
29.57 |
| 2026-10-09 12:00 |
14:47:59.27 |
-12:13:13.1 |
HIP 72174 |
33.90 |
| 2026-10-10 00:00 |
14:48:19.70 |
-12:14:49.6 |
HIP 72373 |
36.07 |
| 2026-10-10 12:00 |
14:48:40.18 |
-12:16:26.1 |
HIP 72596 |
32.24 |
| 2026-10-11 00:00 |
14:49:00.72 |
-12:18:02.6 |
HIP 72596 |
28.84 |