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) |
| 2026-09-20 00:00 |
17:22:33.53 |
-43:24:46.0 |
HIP 85156 |
18.71 |
| 2026-09-20 12:00 |
17:22:35.60 |
-43:24:12.7 |
HIP 85156 |
18.13 |
| 2026-09-21 00:00 |
17:22:37.76 |
-43:23:39.6 |
HIP 85156 |
17.54 |
| 2026-09-21 12:00 |
17:22:40.01 |
-43:23:06.6 |
HIP 85156 |
16.94 |
| 2026-09-22 00:00 |
17:22:42.33 |
-43:22:33.7 |
HIP 85156 |
16.34 |
| 2026-09-22 12:00 |
17:22:44.74 |
-43:22:00.9 |
HIP 85156 |
15.73 |
| 2026-09-23 00:00 |
17:22:47.22 |
-43:21:28.3 |
HIP 85156 |
15.12 |
| 2026-09-23 12:00 |
17:22:49.79 |
-43:20:55.8 |
HIP 85156 |
14.51 |
| 2026-09-24 00:00 |
17:22:52.43 |
-43:20:23.5 |
HIP 85156 |
13.89 |
| 2026-09-24 12:00 |
17:22:55.16 |
-43:19:51.4 |
HIP 85156 |
13.26 |
| 2026-09-25 00:00 |
17:22:57.97 |
-43:19:19.3 |
HIP 85156 |
12.64 |
| 2026-09-25 12:00 |
17:23:00.85 |
-43:18:47.5 |
HIP 85156 |
12.01 |
| 2026-09-26 00:00 |
17:23:03.82 |
-43:18:15.7 |
HIP 85156 |
11.38 |
| 2026-09-26 12:00 |
17:23:06.86 |
-43:17:44.2 |
HIP 85156 |
10.76 |
| 2026-09-27 00:00 |
17:23:09.98 |
-43:17:12.8 |
HIP 85156 |
10.14 |
| 2026-09-27 12:00 |
17:23:13.18 |
-43:16:41.5 |
HIP 85156 |
9.53 |
| 2026-09-28 00:00 |
17:23:16.46 |
-43:16:10.4 |
HIP 85156 |
8.93 |
| 2026-09-28 12:00 |
17:23:19.82 |
-43:15:39.5 |
HIP 85156 |
8.35 |
| 2026-09-29 00:00 |
17:23:23.25 |
-43:15:08.7 |
HIP 85156 |
7.79 |
| 2026-09-29 12:00 |
17:23:26.76 |
-43:14:38.1 |
HIP 85156 |
7.26 |
| 2026-09-30 00:00 |
17:23:30.35 |
-43:14:07.7 |
HIP 85156 |
6.78 |
| 2026-09-30 12:00 |
17:23:34.01 |
-43:13:37.4 |
HIP 85156 |
6.36 |
| 2026-10-01 00:00 |
17:23:37.75 |
-43:13:07.3 |
HIP 85156 |
6.01 |
| 2026-10-01 12:00 |
17:23:41.56 |
-43:12:37.4 |
HIP 85156 |
5.75 |
| 2026-10-02 00:00 |
17:23:45.45 |
-43:12:07.7 |
HIP 85156 |
5.60 |
| 2026-10-02 12:00 |
17:23:49.42 |
-43:11:38.1 |
HIP 85156 |
5.57 |
| 2026-10-03 00:00 |
17:23:53.46 |
-43:11:08.7 |
HIP 85156 |
5.67 |
| 2026-10-03 12:00 |
17:23:57.57 |
-43:10:39.4 |
HIP 85156 |
5.90 |
| 2026-10-04 00:00 |
17:24:01.76 |
-43:10:10.4 |
HIP 85156 |
6.24 |
| 2026-10-04 12:00 |
17:24:06.03 |
-43:09:41.5 |
HIP 85156 |
6.68 |
| 2026-10-05 00:00 |
17:24:10.36 |
-43:09:12.8 |
HIP 85156 |
7.22 |
| 2026-10-05 12:00 |
17:24:14.78 |
-43:08:44.3 |
HIP 85156 |
7.82 |
| 2026-10-06 00:00 |
17:24:19.26 |
-43:08:16.0 |
HIP 85156 |
8.49 |
| 2026-10-06 12:00 |
17:24:23.82 |
-43:07:47.9 |
HIP 85156 |
9.20 |
| 2026-10-07 00:00 |
17:24:28.45 |
-43:07:19.9 |
HIP 85156 |
9.96 |
| 2026-10-07 12:00 |
17:24:33.15 |
-43:06:52.2 |
HIP 85156 |
10.76 |
| 2026-10-08 00:00 |
17:24:37.92 |
-43:06:24.6 |
HIP 85156 |
11.59 |
| 2026-10-08 12:00 |
17:24:42.77 |
-43:05:57.2 |
HIP 85156 |
12.44 |
| 2026-10-09 00:00 |
17:24:47.68 |
-43:05:30.0 |
HIP 85156 |
13.32 |
| 2026-10-09 12:00 |
17:24:52.67 |
-43:05:03.1 |
HIP 85156 |
14.22 |
| 2026-10-10 00:00 |
17:24:57.73 |
-43:04:36.3 |
HIP 85156 |
15.14 |
| 2026-10-10 12:00 |
17:25:02.86 |
-43:04:09.7 |
HIP 85156 |
16.08 |
| 2026-10-11 00:00 |
17:25:08.05 |
-43:03:43.3 |
HIP 85367 |
16.80 |