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) |
| 2026-07-29 00:00 |
17:27:00.28 |
-44:26:37.7 |
HIP 85357 |
12.23 |
| 2026-07-29 12:00 |
17:26:53.41 |
-44:26:07.2 |
HIP 85357 |
12.26 |
| 2026-07-30 00:00 |
17:26:46.62 |
-44:25:36.5 |
HIP 85357 |
12.43 |
| 2026-07-30 12:00 |
17:26:39.89 |
-44:25:05.6 |
HIP 85357 |
12.75 |
| 2026-07-31 00:00 |
17:26:33.25 |
-44:24:34.4 |
HIP 85357 |
13.19 |
| 2026-07-31 12:00 |
17:26:26.67 |
-44:24:03.1 |
HIP 85357 |
13.74 |
| 2026-08-01 00:00 |
17:26:20.17 |
-44:23:31.6 |
HIP 85357 |
14.39 |
| 2026-08-01 12:00 |
17:26:13.75 |
-44:22:59.8 |
HIP 85357 |
15.12 |
| 2026-08-02 00:00 |
17:26:07.40 |
-44:22:27.9 |
HIP 85357 |
15.91 |
| 2026-08-02 12:00 |
17:26:01.13 |
-44:21:55.8 |
HIP 85357 |
16.76 |
| 2026-08-03 00:00 |
17:25:54.93 |
-44:21:23.5 |
HIP 85357 |
17.65 |
| 2026-08-03 12:00 |
17:25:48.81 |
-44:20:51.1 |
HIP 85357 |
18.58 |
| 2026-08-04 00:00 |
17:25:42.77 |
-44:20:18.4 |
HIP 85162 |
19.22 |
| 2026-08-04 12:00 |
17:25:36.81 |
-44:19:45.6 |
HIP 85162 |
18.03 |
| 2026-08-05 00:00 |
17:25:30.92 |
-44:19:12.6 |
HIP 85162 |
16.85 |
| 2026-08-05 12:00 |
17:25:25.11 |
-44:18:39.5 |
HIP 85162 |
15.68 |
| 2026-08-06 00:00 |
17:25:19.39 |
-44:18:06.2 |
HIP 85162 |
14.52 |
| 2026-08-06 12:00 |
17:25:13.74 |
-44:17:32.7 |
HIP 85162 |
13.37 |
| 2026-08-07 00:00 |
17:25:08.17 |
-44:16:59.1 |
HIP 85162 |
12.23 |
| 2026-08-07 12:00 |
17:25:02.68 |
-44:16:25.3 |
HIP 85162 |
11.11 |
| 2026-08-08 00:00 |
17:24:57.27 |
-44:15:51.4 |
HIP 85162 |
10.00 |
| 2026-08-08 12:00 |
17:24:51.94 |
-44:15:17.3 |
HIP 85162 |
8.90 |
| 2026-08-09 00:00 |
17:24:46.69 |
-44:14:43.1 |
HIP 85162 |
7.81 |
| 2026-08-09 12:00 |
17:24:41.53 |
-44:14:08.8 |
HIP 85162 |
6.73 |
| 2026-08-10 00:00 |
17:24:36.44 |
-44:13:34.3 |
HIP 85162 |
5.67 |
| 2026-08-10 12:00 |
17:24:31.44 |
-44:12:59.7 |
HIP 85162 |
4.62 |
| 2026-08-11 00:00 |
17:24:26.53 |
-44:12:25.0 |
HIP 85162 |
3.59 |
| 2026-08-11 12:00 |
17:24:21.69 |
-44:11:50.2 |
HIP 85162 |
2.59 |
| 2026-08-12 00:00 |
17:24:16.94 |
-44:11:15.2 |
HIP 85162 |
1.65 |
| 2026-08-12 12:00 |
17:24:12.28 |
-44:10:40.2 |
HIP 85162 |
0.93 |
| 2026-08-13 00:00 |
17:24:07.69 |
-44:10:05.0 |
HIP 85162 |
1.02 |
| 2026-08-13 12:00 |
17:24:03.20 |
-44:09:29.7 |
HIP 85162 |
1.79 |
| 2026-08-14 00:00 |
17:23:58.78 |
-44:08:54.4 |
HIP 85162 |
2.70 |
| 2026-08-14 12:00 |
17:23:54.46 |
-44:08:18.9 |
HIP 85162 |
3.64 |
| 2026-08-15 00:00 |
17:23:50.22 |
-44:07:43.3 |
HIP 85162 |
4.58 |
| 2026-08-15 12:00 |
17:23:46.06 |
-44:07:07.7 |
HIP 85162 |
5.51 |
| 2026-08-16 00:00 |
17:23:41.99 |
-44:06:32.0 |
HIP 85162 |
6.44 |
| 2026-08-16 12:00 |
17:23:38.00 |
-44:05:56.1 |
HIP 85162 |
7.36 |
| 2026-08-17 00:00 |
17:23:34.10 |
-44:05:20.3 |
HIP 85162 |
8.27 |
| 2026-08-17 12:00 |
17:23:30.29 |
-44:04:44.3 |
HIP 85162 |
9.17 |
| 2026-08-18 00:00 |
17:23:26.57 |
-44:04:08.3 |
HIP 85162 |
10.06 |
| 2026-08-18 12:00 |
17:23:22.93 |
-44:03:32.2 |
HIP 85168 |
10.70 |
| 2026-08-19 00:00 |
17:23:19.37 |
-44:02:56.0 |
HIP 85168 |
11.10 |