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) |
| 2026-09-20 00:00 |
09:50:50.21 |
-20:23:49.9 |
HIP 48291 |
22.42 |
| 2026-09-20 12:00 |
09:50:51.80 |
-20:24:04.4 |
HIP 48291 |
22.20 |
| 2026-09-21 00:00 |
09:50:53.39 |
-20:24:19.0 |
HIP 48291 |
21.99 |
| 2026-09-21 12:00 |
09:50:54.96 |
-20:24:33.7 |
HIP 48291 |
21.78 |
| 2026-09-22 00:00 |
09:50:56.53 |
-20:24:48.5 |
HIP 48291 |
21.58 |
| 2026-09-22 12:00 |
09:50:58.08 |
-20:25:03.3 |
HIP 48291 |
21.39 |
| 2026-09-23 00:00 |
09:50:59.63 |
-20:25:18.2 |
HIP 48291 |
21.20 |
| 2026-09-23 12:00 |
09:51:01.17 |
-20:25:33.2 |
HIP 48291 |
21.02 |
| 2026-09-24 00:00 |
09:51:02.70 |
-20:25:48.3 |
HIP 48291 |
20.84 |
| 2026-09-24 12:00 |
09:51:04.22 |
-20:26:03.4 |
HIP 48291 |
20.67 |
| 2026-09-25 00:00 |
09:51:05.73 |
-20:26:18.6 |
HIP 48291 |
20.50 |
| 2026-09-25 12:00 |
09:51:07.23 |
-20:26:33.9 |
HIP 48291 |
20.35 |
| 2026-09-26 00:00 |
09:51:08.72 |
-20:26:49.2 |
HIP 48291 |
20.19 |
| 2026-09-26 12:00 |
09:51:10.21 |
-20:27:04.6 |
HIP 48291 |
20.05 |
| 2026-09-27 00:00 |
09:51:11.68 |
-20:27:20.0 |
HIP 48291 |
19.91 |
| 2026-09-27 12:00 |
09:51:13.14 |
-20:27:35.6 |
HIP 48291 |
19.78 |
| 2026-09-28 00:00 |
09:51:14.59 |
-20:27:51.2 |
HIP 48291 |
19.65 |
| 2026-09-28 12:00 |
09:51:16.04 |
-20:28:06.8 |
HIP 48291 |
19.53 |
| 2026-09-29 00:00 |
09:51:17.47 |
-20:28:22.5 |
HIP 48291 |
19.42 |
| 2026-09-29 12:00 |
09:51:18.89 |
-20:28:38.3 |
HIP 48291 |
19.32 |
| 2026-09-30 00:00 |
09:51:20.30 |
-20:28:54.1 |
HIP 48291 |
19.22 |
| 2026-09-30 12:00 |
09:51:21.70 |
-20:29:10.0 |
HIP 48291 |
19.12 |
| 2026-10-01 00:00 |
09:51:23.09 |
-20:29:26.0 |
HIP 48291 |
19.04 |
| 2026-10-01 12:00 |
09:51:24.47 |
-20:29:42.0 |
HIP 48291 |
18.96 |
| 2026-10-02 00:00 |
09:51:25.84 |
-20:29:58.0 |
HIP 48291 |
18.89 |
| 2026-10-02 12:00 |
09:51:27.20 |
-20:30:14.1 |
HIP 48291 |
18.83 |
| 2026-10-03 00:00 |
09:51:28.54 |
-20:30:30.3 |
HIP 48291 |
18.77 |
| 2026-10-03 12:00 |
09:51:29.88 |
-20:30:46.5 |
HIP 48291 |
18.72 |
| 2026-10-04 00:00 |
09:51:31.20 |
-20:31:02.8 |
HIP 48291 |
18.67 |
| 2026-10-04 12:00 |
09:51:32.51 |
-20:31:19.1 |
HIP 48291 |
18.64 |
| 2026-10-05 00:00 |
09:51:33.82 |
-20:31:35.5 |
HIP 48291 |
18.61 |
| 2026-10-05 12:00 |
09:51:35.10 |
-20:31:51.9 |
HIP 48291 |
18.58 |
| 2026-10-06 00:00 |
09:51:36.38 |
-20:32:08.3 |
HIP 48291 |
18.56 |
| 2026-10-06 12:00 |
09:51:37.65 |
-20:32:24.8 |
HIP 48291 |
18.55 |
| 2026-10-07 00:00 |
09:51:38.90 |
-20:32:41.4 |
HIP 48291 |
18.55 |
| 2026-10-07 12:00 |
09:51:40.14 |
-20:32:58.0 |
HIP 48291 |
18.55 |
| 2026-10-08 00:00 |
09:51:41.37 |
-20:33:14.6 |
HIP 48291 |
18.56 |
| 2026-10-08 12:00 |
09:51:42.59 |
-20:33:31.3 |
HIP 48291 |
18.57 |
| 2026-10-09 00:00 |
09:51:43.79 |
-20:33:48.0 |
HIP 48291 |
18.59 |
| 2026-10-09 12:00 |
09:51:44.99 |
-20:34:04.7 |
HIP 48291 |
18.62 |
| 2026-10-10 00:00 |
09:51:46.17 |
-20:34:21.5 |
HIP 48291 |
18.65 |
| 2026-10-10 12:00 |
09:51:47.33 |
-20:34:38.3 |
HIP 48291 |
18.68 |
| 2026-10-11 00:00 |
09:51:48.49 |
-20:34:55.2 |
HIP 48291 |
18.73 |