メタデータ
| 項目 |
値 |
| Designation |
P/2021 Q5 (ATLAS) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2021-08-30T10:00:46.546560Z |
| Orbit solution date (soln_date, UTC) |
2025-01-14T17:42:18Z |
| Obs used |
274 |
| NEO |
Yes |
| M1 |
15.800 |
| K1 |
4.500 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2021-08-29T14:33:45.619200Z |
| Discovery magnitude (MPC) |
17.59 o |
| Discovery observatory (MPC) |
T05 · ATLAS-HKO, Haleakala |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2021-09-20.0000000 |
| e |
0.62395172 |
| q (au) |
1.234397 |
| a (au) |
3.282550 |
| i (deg) |
10.733839 |
| Ω (om, deg) |
239.770616 |
| ω (w, deg) |
180.879852 |
| M (ma, deg) |
3.411076 |
等級
散乱 + 全体線形
$$
M_a = (14.774 + 2.320\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
14.774 |
| n |
2.320 |
| gf |
1.000 |
| gb |
-0.998 |
| 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
ファインディングチャート
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
18:30:06.78 |
-12:53:01.5 |
HIP 90701 |
17.81 |
| 2026-07-29 12:00 |
18:29:43.31 |
-12:53:26.3 |
HIP 90572 |
12.83 |
| 2026-07-30 00:00 |
18:29:20.04 |
-12:53:51.7 |
HIP 90572 |
7.47 |
| 2026-07-30 12:00 |
18:28:56.97 |
-12:54:17.6 |
HIP 90572 |
3.42 |
| 2026-07-31 00:00 |
18:28:34.10 |
-12:54:44.1 |
HIP 90552 |
5.15 |
| 2026-07-31 12:00 |
18:28:11.44 |
-12:55:11.1 |
HIP 90552 |
7.72 |
| 2026-08-01 00:00 |
18:27:48.98 |
-12:55:38.7 |
HIP 90552 |
12.36 |
| 2026-08-01 12:00 |
18:27:26.74 |
-12:56:06.9 |
HIP 90552 |
17.44 |
| 2026-08-02 00:00 |
18:27:04.72 |
-12:56:35.5 |
HIP 90552 |
22.64 |
| 2026-08-02 12:00 |
18:26:42.92 |
-12:57:04.7 |
HIP 90303 |
23.43 |
| 2026-08-03 00:00 |
18:26:21.34 |
-12:57:34.4 |
HIP 90303 |
20.23 |
| 2026-08-03 12:00 |
18:26:00.00 |
-12:58:04.7 |
HIP 90303 |
18.07 |
| 2026-08-04 00:00 |
18:25:38.88 |
-12:58:35.4 |
HIP 90303 |
17.28 |
| 2026-08-04 12:00 |
18:25:18.00 |
-12:59:06.7 |
HIP 90303 |
18.01 |
| 2026-08-05 00:00 |
18:24:57.35 |
-12:59:38.5 |
HIP 90234 |
19.60 |
| 2026-08-05 12:00 |
18:24:36.95 |
-13:00:10.8 |
HIP 90234 |
19.69 |
| 2026-08-06 00:00 |
18:24:16.80 |
-13:00:43.6 |
HIP 90234 |
21.00 |
| 2026-08-06 12:00 |
18:23:56.89 |
-13:01:16.8 |
HIP 90115 |
22.04 |
| 2026-08-07 00:00 |
18:23:37.23 |
-13:01:50.6 |
HIP 90115 |
21.27 |
| 2026-08-07 12:00 |
18:23:17.83 |
-13:02:24.8 |
HIP 90115 |
21.58 |
| 2026-08-08 00:00 |
18:22:58.69 |
-13:02:59.5 |
HIP 90115 |
22.90 |
| 2026-08-08 12:00 |
18:22:39.81 |
-13:03:34.7 |
HIP 90115 |
25.02 |
| 2026-08-09 00:00 |
18:22:21.20 |
-13:04:10.4 |
HIP 90115 |
27.73 |
| 2026-08-09 12:00 |
18:22:02.85 |
-13:04:46.5 |
HIP 90115 |
30.84 |
| 2026-08-10 00:00 |
18:21:44.77 |
-13:05:23.0 |
HIP 90115 |
34.23 |
| 2026-08-10 12:00 |
18:21:26.97 |
-13:06:00.0 |
HIP 90115 |
37.80 |
| 2026-08-11 00:00 |
18:21:09.44 |
-13:06:37.5 |
HIP 90115 |
41.47 |
| 2026-08-11 12:00 |
18:20:52.20 |
-13:07:15.3 |
HIP 89747 |
38.06 |
| 2026-08-12 00:00 |
18:20:35.23 |
-13:07:53.6 |
HIP 89747 |
34.62 |
| 2026-08-12 12:00 |
18:20:18.55 |
-13:08:32.3 |
HIP 89747 |
31.40 |
| 2026-08-13 00:00 |
18:20:02.16 |
-13:09:11.4 |
HIP 89747 |
28.44 |
| 2026-08-13 12:00 |
18:19:46.06 |
-13:09:50.9 |
HIP 89747 |
25.81 |
| 2026-08-14 00:00 |
18:19:30.25 |
-13:10:30.8 |
HIP 89747 |
23.58 |
| 2026-08-14 12:00 |
18:19:14.74 |
-13:11:11.1 |
HIP 89747 |
21.83 |
| 2026-08-15 00:00 |
18:18:59.52 |
-13:11:51.7 |
HIP 89747 |
20.65 |
| 2026-08-15 12:00 |
18:18:44.60 |
-13:12:32.7 |
HIP 89747 |
20.09 |
| 2026-08-16 00:00 |
18:18:29.98 |
-13:13:14.1 |
HIP 89747 |
20.19 |
| 2026-08-16 12:00 |
18:18:15.67 |
-13:13:55.8 |
HIP 89747 |
20.87 |
| 2026-08-17 00:00 |
18:18:01.66 |
-13:14:37.9 |
HIP 89747 |
22.07 |
| 2026-08-17 12:00 |
18:17:47.95 |
-13:15:20.3 |
HIP 89672 |
23.27 |
| 2026-08-18 00:00 |
18:17:34.56 |
-13:16:03.0 |
HIP 89672 |
24.54 |
| 2026-08-18 12:00 |
18:17:21.47 |
-13:16:46.1 |
HIP 89672 |
26.15 |
| 2026-08-19 00:00 |
18:17:08.69 |
-13:17:29.5 |
HIP 89508 |
24.70 |