メタデータ
| 項目 |
値 |
| Designation |
C/1989 R1 (Helin-Roman) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1989-08-20T06:57:23.126400Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:38Z |
| Obs used |
19 |
| NEO |
- |
| M1 |
- |
| K1 |
- |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
1989-09-20.0000000 |
| e |
0.99999476 |
| q (au) |
1.324504 |
| a (au) |
252659.816775 |
| i (deg) |
128.133260 |
| Ω (om, deg) |
128.609412 |
| ω (w, deg) |
154.909426 |
| M (ma, deg) |
0.000000 |
等級
散乱 + 全体線形
$$
M_a = (13.756 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
13.756 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-1.000 |
| k |
0.800 |
| 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) |
| 2026-06-01 00:00 |
09:45:13.91 |
-20:20:56.0 |
HIP 47866 |
1.69 |
| 2026-06-01 12:00 |
09:45:14.42 |
-20:20:42.0 |
HIP 47866 |
1.52 |
| 2026-06-02 00:00 |
09:45:14.95 |
-20:20:28.2 |
HIP 47866 |
1.37 |
| 2026-06-02 12:00 |
09:45:15.50 |
-20:20:14.4 |
HIP 47866 |
1.25 |
| 2026-06-03 00:00 |
09:45:16.06 |
-20:20:00.8 |
HIP 47866 |
1.17 |
| 2026-06-03 12:00 |
09:45:16.63 |
-20:19:47.2 |
HIP 47866 |
1.15 |
| 2026-06-04 00:00 |
09:45:17.22 |
-20:19:33.8 |
HIP 47866 |
1.19 |
| 2026-06-04 12:00 |
09:45:17.83 |
-20:19:20.5 |
HIP 47866 |
1.27 |
| 2026-06-05 00:00 |
09:45:18.45 |
-20:19:07.3 |
HIP 47866 |
1.40 |
| 2026-06-05 12:00 |
09:45:19.09 |
-20:18:54.2 |
HIP 47866 |
1.56 |
| 2026-06-06 00:00 |
09:45:19.74 |
-20:18:41.3 |
HIP 47866 |
1.74 |
| 2026-06-06 12:00 |
09:45:20.40 |
-20:18:28.4 |
HIP 47866 |
1.94 |
| 2026-06-07 00:00 |
09:45:21.08 |
-20:18:15.7 |
HIP 47866 |
2.15 |
| 2026-06-07 12:00 |
09:45:21.78 |
-20:18:03.0 |
HIP 47866 |
2.37 |
| 2026-06-08 00:00 |
09:45:22.49 |
-20:17:50.5 |
HIP 47866 |
2.60 |
| 2026-06-08 12:00 |
09:45:23.22 |
-20:17:38.1 |
HIP 47866 |
2.83 |
| 2026-06-09 00:00 |
09:45:23.96 |
-20:17:25.8 |
HIP 47866 |
3.07 |
| 2026-06-09 12:00 |
09:45:24.71 |
-20:17:13.7 |
HIP 47866 |
3.31 |
| 2026-06-10 00:00 |
09:45:25.48 |
-20:17:01.7 |
HIP 47866 |
3.56 |
| 2026-06-10 12:00 |
09:45:26.27 |
-20:16:49.7 |
HIP 47866 |
3.81 |
| 2026-06-11 00:00 |
09:45:27.07 |
-20:16:37.9 |
HIP 47866 |
4.06 |
| 2026-06-11 12:00 |
09:45:27.88 |
-20:16:26.3 |
HIP 47866 |
4.31 |
| 2026-06-12 00:00 |
09:45:28.71 |
-20:16:14.7 |
HIP 47866 |
4.56 |
| 2026-06-12 12:00 |
09:45:29.55 |
-20:16:03.3 |
HIP 47866 |
4.82 |
| 2026-06-13 00:00 |
09:45:30.41 |
-20:15:52.0 |
HIP 47866 |
5.08 |
| 2026-06-13 12:00 |
09:45:31.28 |
-20:15:40.8 |
HIP 47866 |
5.33 |
| 2026-06-14 00:00 |
09:45:32.17 |
-20:15:29.7 |
HIP 47866 |
5.59 |
| 2026-06-14 12:00 |
09:45:33.07 |
-20:15:18.8 |
HIP 47866 |
5.86 |
| 2026-06-15 00:00 |
09:45:33.98 |
-20:15:08.0 |
HIP 47866 |
6.12 |
| 2026-06-15 12:00 |
09:45:34.91 |
-20:14:57.4 |
HIP 47866 |
6.38 |
| 2026-06-16 00:00 |
09:45:35.85 |
-20:14:46.8 |
HIP 47866 |
6.65 |
| 2026-06-16 12:00 |
09:45:36.81 |
-20:14:36.4 |
HIP 47866 |
6.92 |
| 2026-06-17 00:00 |
09:45:37.77 |
-20:14:26.1 |
HIP 47866 |
7.18 |
| 2026-06-17 12:00 |
09:45:38.76 |
-20:14:16.0 |
HIP 47866 |
7.45 |
| 2026-06-18 00:00 |
09:45:39.75 |
-20:14:05.9 |
HIP 47866 |
7.72 |
| 2026-06-18 12:00 |
09:45:40.76 |
-20:13:56.1 |
HIP 47866 |
7.99 |
| 2026-06-19 00:00 |
09:45:41.79 |
-20:13:46.3 |
HIP 47866 |
8.27 |
| 2026-06-19 12:00 |
09:45:42.82 |
-20:13:36.7 |
HIP 47866 |
8.54 |
| 2026-06-20 00:00 |
09:45:43.87 |
-20:13:27.2 |
HIP 47866 |
8.82 |
| 2026-06-20 12:00 |
09:45:44.93 |
-20:13:17.8 |
HIP 47866 |
9.09 |
| 2026-06-21 00:00 |
09:45:46.01 |
-20:13:08.6 |
HIP 47866 |
9.37 |
| 2026-06-21 12:00 |
09:45:47.10 |
-20:12:59.5 |
HIP 47866 |
9.65 |
| 2026-06-22 00:00 |
09:45:48.20 |
-20:12:50.6 |
HIP 47866 |
9.93 |