メタデータ
| 項目 |
値 |
| Designation |
C/2021 O1 (Nishimura) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-08-13T22:16:11.570880Z |
| Orbit solution date (soln_date, UTC) |
2023-04-24T19:06:44Z |
| Obs used |
59 |
| NEO |
- |
| M1 |
10.800 |
| K1 |
10.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2021-07-21T18:47:36.384000Z |
| Discovery magnitude (MPC) |
10.70 T |
| Discovery observatory (MPC) |
247 · Roving Observer |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2021-07-26.0000000 |
| e |
1.00305367 |
| q (au) |
0.787409 |
| a (au) |
-257.856271 |
| i (deg) |
27.567888 |
| Ω (om, deg) |
41.631614 |
| ω (w, deg) |
74.438198 |
| M (ma, deg) |
-0.004505 |
等級
散乱 + 全体線形
$$
M_a = (9.855 + 3.673\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
9.855 |
| n |
3.673 |
| 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
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
17:45:21.23 |
-44:47:52.5 |
HIP 86956 |
14.12 |
| 2026-06-01 12:00 |
17:45:11.14 |
-44:48:04.9 |
HIP 86956 |
15.41 |
| 2026-06-02 00:00 |
17:45:01.02 |
-44:48:16.9 |
HIP 86788 |
14.55 |
| 2026-06-02 12:00 |
17:44:50.88 |
-44:48:28.5 |
HIP 86788 |
13.47 |
| 2026-06-03 00:00 |
17:44:40.71 |
-44:48:39.7 |
HIP 86788 |
12.55 |
| 2026-06-03 12:00 |
17:44:30.52 |
-44:48:50.4 |
HIP 86788 |
11.83 |
| 2026-06-04 00:00 |
17:44:20.31 |
-44:49:00.7 |
HIP 86788 |
11.35 |
| 2026-06-04 12:00 |
17:44:10.07 |
-44:49:10.6 |
HIP 86788 |
11.14 |
| 2026-06-05 00:00 |
17:43:59.81 |
-44:49:20.0 |
HIP 86718 |
9.87 |
| 2026-06-05 12:00 |
17:43:49.54 |
-44:49:29.0 |
HIP 86718 |
8.24 |
| 2026-06-06 00:00 |
17:43:39.24 |
-44:49:37.6 |
HIP 86718 |
6.71 |
| 2026-06-06 12:00 |
17:43:28.93 |
-44:49:45.8 |
HIP 86718 |
5.36 |
| 2026-06-07 00:00 |
17:43:18.60 |
-44:49:53.5 |
HIP 86718 |
4.36 |
| 2026-06-07 12:00 |
17:43:08.25 |
-44:50:00.8 |
HIP 86718 |
4.01 |
| 2026-06-08 00:00 |
17:42:57.89 |
-44:50:07.6 |
HIP 86718 |
4.46 |
| 2026-06-08 12:00 |
17:42:47.51 |
-44:50:14.0 |
HIP 86718 |
5.51 |
| 2026-06-09 00:00 |
17:42:37.12 |
-44:50:20.0 |
HIP 86718 |
6.90 |
| 2026-06-09 12:00 |
17:42:26.72 |
-44:50:25.6 |
HIP 86718 |
8.47 |
| 2026-06-10 00:00 |
17:42:16.31 |
-44:50:30.7 |
HIP 86718 |
10.12 |
| 2026-06-10 12:00 |
17:42:05.88 |
-44:50:35.4 |
HIP 86718 |
11.84 |
| 2026-06-11 00:00 |
17:41:55.45 |
-44:50:39.6 |
HIP 86718 |
13.59 |
| 2026-06-11 12:00 |
17:41:45.01 |
-44:50:43.4 |
HIP 86718 |
15.36 |
| 2026-06-12 00:00 |
17:41:34.56 |
-44:50:46.8 |
HIP 86718 |
17.15 |
| 2026-06-12 12:00 |
17:41:24.11 |
-44:50:49.7 |
HIP 86718 |
18.95 |
| 2026-06-13 00:00 |
17:41:13.65 |
-44:50:52.2 |
HIP 86718 |
20.76 |
| 2026-06-13 12:00 |
17:41:03.19 |
-44:50:54.2 |
HIP 86464 |
20.94 |
| 2026-06-14 00:00 |
17:40:52.72 |
-44:50:55.9 |
HIP 86464 |
19.95 |
| 2026-06-14 12:00 |
17:40:42.25 |
-44:50:57.0 |
HIP 86464 |
19.10 |
| 2026-06-15 00:00 |
17:40:31.78 |
-44:50:57.8 |
HIP 86464 |
18.40 |
| 2026-06-15 12:00 |
17:40:21.32 |
-44:50:58.1 |
HIP 86464 |
17.88 |
| 2026-06-16 00:00 |
17:40:10.85 |
-44:50:58.0 |
HIP 86464 |
17.54 |
| 2026-06-16 12:00 |
17:40:00.39 |
-44:50:57.4 |
HIP 86464 |
17.40 |
| 2026-06-17 00:00 |
17:39:49.93 |
-44:50:56.4 |
HIP 86464 |
17.47 |
| 2026-06-17 12:00 |
17:39:39.47 |
-44:50:54.9 |
HIP 86464 |
17.74 |
| 2026-06-18 00:00 |
17:39:29.02 |
-44:50:53.1 |
HIP 86464 |
18.19 |
| 2026-06-18 12:00 |
17:39:18.58 |
-44:50:50.8 |
HIP 86464 |
18.83 |
| 2026-06-19 00:00 |
17:39:08.15 |
-44:50:48.0 |
HIP 86464 |
19.62 |
| 2026-06-19 12:00 |
17:38:57.72 |
-44:50:44.9 |
HIP 86464 |
20.56 |
| 2026-06-20 00:00 |
17:38:47.31 |
-44:50:41.3 |
HIP 86464 |
21.61 |
| 2026-06-20 12:00 |
17:38:36.90 |
-44:50:37.2 |
HIP 86324 |
22.47 |
| 2026-06-21 00:00 |
17:38:26.51 |
-44:50:32.8 |
HIP 86324 |
22.34 |
| 2026-06-21 12:00 |
17:38:16.13 |
-44:50:27.9 |
HIP 86324 |
22.37 |
| 2026-06-22 00:00 |
17:38:05.77 |
-44:50:22.6 |
HIP 86324 |
22.55 |