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) |
| 2026-03-26 00:00 |
09:46:30.46 |
-21:00:45.8 |
HIP 47931 |
22.49 |
| 2026-03-26 12:00 |
09:46:28.90 |
-21:00:28.0 |
HIP 47931 |
22.68 |
| 2026-03-27 00:00 |
09:46:27.36 |
-21:00:10.1 |
HIP 47931 |
22.88 |
| 2026-03-27 12:00 |
09:46:25.83 |
-20:59:52.1 |
HIP 47931 |
23.09 |
| 2026-03-28 00:00 |
09:46:24.31 |
-20:59:34.1 |
HIP 47931 |
23.30 |
| 2026-03-28 12:00 |
09:46:22.80 |
-20:59:16.0 |
HIP 47931 |
23.53 |
| 2026-03-29 00:00 |
09:46:21.30 |
-20:58:57.9 |
HIP 47931 |
23.77 |
| 2026-03-29 12:00 |
09:46:19.82 |
-20:58:39.7 |
HIP 47856 |
23.75 |
| 2026-03-30 00:00 |
09:46:18.35 |
-20:58:21.5 |
HIP 47856 |
23.30 |
| 2026-03-30 12:00 |
09:46:16.89 |
-20:58:03.2 |
HIP 47856 |
22.84 |
| 2026-03-31 00:00 |
09:46:15.45 |
-20:57:44.9 |
HIP 47856 |
22.39 |
| 2026-03-31 12:00 |
09:46:14.01 |
-20:57:26.5 |
HIP 47856 |
21.95 |
| 2026-04-01 00:00 |
09:46:12.59 |
-20:57:08.1 |
HIP 47856 |
21.50 |
| 2026-04-01 12:00 |
09:46:11.18 |
-20:56:49.7 |
HIP 47856 |
21.05 |
| 2026-04-02 00:00 |
09:46:09.79 |
-20:56:31.1 |
HIP 47856 |
20.61 |
| 2026-04-02 12:00 |
09:46:08.41 |
-20:56:12.6 |
HIP 47856 |
20.17 |
| 2026-04-03 00:00 |
09:46:07.04 |
-20:55:54.0 |
HIP 47856 |
19.73 |
| 2026-04-03 12:00 |
09:46:05.68 |
-20:55:35.4 |
HIP 47856 |
19.29 |
| 2026-04-04 00:00 |
09:46:04.34 |
-20:55:16.7 |
HIP 47856 |
18.85 |
| 2026-04-04 12:00 |
09:46:03.01 |
-20:54:58.0 |
HIP 47856 |
18.41 |
| 2026-04-05 00:00 |
09:46:01.70 |
-20:54:39.2 |
HIP 47856 |
17.98 |
| 2026-04-05 12:00 |
09:46:00.40 |
-20:54:20.5 |
HIP 47856 |
17.55 |
| 2026-04-06 00:00 |
09:45:59.11 |
-20:54:01.7 |
HIP 47856 |
17.11 |
| 2026-04-06 12:00 |
09:45:57.83 |
-20:53:42.8 |
HIP 47856 |
16.68 |
| 2026-04-07 00:00 |
09:45:56.57 |
-20:53:23.9 |
HIP 47856 |
16.26 |
| 2026-04-07 12:00 |
09:45:55.33 |
-20:53:05.0 |
HIP 47856 |
15.83 |
| 2026-04-08 00:00 |
09:45:54.09 |
-20:52:46.1 |
HIP 47856 |
15.41 |
| 2026-04-08 12:00 |
09:45:52.88 |
-20:52:27.2 |
HIP 47856 |
14.98 |
| 2026-04-09 00:00 |
09:45:51.67 |
-20:52:08.2 |
HIP 47856 |
14.56 |
| 2026-04-09 12:00 |
09:45:50.48 |
-20:51:49.2 |
HIP 47856 |
14.14 |
| 2026-04-10 00:00 |
09:45:49.30 |
-20:51:30.1 |
HIP 47856 |
13.72 |
| 2026-04-10 12:00 |
09:45:48.14 |
-20:51:11.1 |
HIP 47856 |
13.31 |
| 2026-04-11 00:00 |
09:45:47.00 |
-20:50:52.0 |
HIP 47856 |
12.89 |
| 2026-04-11 12:00 |
09:45:45.86 |
-20:50:32.9 |
HIP 47856 |
12.48 |
| 2026-04-12 00:00 |
09:45:44.75 |
-20:50:13.8 |
HIP 47856 |
12.07 |
| 2026-04-12 12:00 |
09:45:43.64 |
-20:49:54.7 |
HIP 47856 |
11.66 |
| 2026-04-13 00:00 |
09:45:42.55 |
-20:49:35.6 |
HIP 47856 |
11.26 |
| 2026-04-13 12:00 |
09:45:41.48 |
-20:49:16.4 |
HIP 47856 |
10.85 |
| 2026-04-14 00:00 |
09:45:40.42 |
-20:48:57.3 |
HIP 47856 |
10.45 |
| 2026-04-14 12:00 |
09:45:39.38 |
-20:48:38.1 |
HIP 47856 |
10.05 |
| 2026-04-15 00:00 |
09:45:38.35 |
-20:48:19.0 |
HIP 47856 |
9.65 |
| 2026-04-15 12:00 |
09:45:37.34 |
-20:47:59.8 |
HIP 47856 |
9.25 |
| 2026-04-16 00:00 |
09:45:36.34 |
-20:47:40.6 |
HIP 47856 |
8.85 |