メタデータ
| 項目 |
値 |
| Designation |
C/2021 S1 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2022-02-28T22:41:40.444800Z |
| Orbit solution date (soln_date, UTC) |
2024-06-06T23:12:23Z |
| Obs used |
476 |
| NEO |
- |
| M1 |
6.700 |
| K1 |
10.000 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2021-09-27T13:41:00.096000Z |
| Discovery magnitude (MPC) |
17.82 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) |
2022-03-23.0000000 |
| e |
1.00095649 |
| q (au) |
6.119212 |
| a (au) |
-6397.577104 |
| i (deg) |
52.088959 |
| Ω (om, deg) |
299.873636 |
| ω (w, deg) |
148.188635 |
| M (ma, deg) |
0.000042 |
等級
散乱 + 全体線形
$$
M_a = (5.453 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
5.453 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.717 |
| k |
0.800 |
| δ90 |
9.999 |
| 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 |
10:02:14.13 |
-30:21:43.3 |
HIP 49091 |
13.63 |
| 2026-09-20 12:00 |
10:02:24.10 |
-30:23:33.6 |
HIP 49222 |
12.35 |
| 2026-09-21 00:00 |
10:02:34.04 |
-30:25:24.4 |
HIP 49222 |
9.82 |
| 2026-09-21 12:00 |
10:02:43.93 |
-30:27:15.6 |
HIP 49222 |
7.49 |
| 2026-09-22 00:00 |
10:02:53.80 |
-30:29:07.3 |
HIP 49222 |
5.62 |
| 2026-09-22 12:00 |
10:03:03.62 |
-30:30:59.5 |
HIP 49222 |
4.79 |
| 2026-09-23 00:00 |
10:03:13.41 |
-30:32:52.2 |
HIP 49222 |
5.49 |
| 2026-09-23 12:00 |
10:03:23.15 |
-30:34:45.3 |
HIP 49222 |
7.28 |
| 2026-09-24 00:00 |
10:03:32.86 |
-30:36:38.8 |
HIP 49222 |
9.58 |
| 2026-09-24 12:00 |
10:03:42.53 |
-30:38:32.8 |
HIP 49222 |
12.09 |
| 2026-09-25 00:00 |
10:03:52.16 |
-30:40:27.3 |
HIP 49222 |
14.71 |
| 2026-09-25 12:00 |
10:04:01.75 |
-30:42:22.2 |
HIP 49222 |
17.39 |
| 2026-09-26 00:00 |
10:04:11.30 |
-30:44:17.5 |
HIP 49222 |
20.09 |
| 2026-09-26 12:00 |
10:04:20.81 |
-30:46:13.3 |
HIP 49450 |
19.54 |
| 2026-09-27 00:00 |
10:04:30.27 |
-30:48:09.5 |
HIP 49450 |
16.97 |
| 2026-09-27 12:00 |
10:04:39.70 |
-30:50:06.1 |
HIP 49450 |
14.48 |
| 2026-09-28 00:00 |
10:04:49.08 |
-30:52:03.2 |
HIP 49450 |
12.15 |
| 2026-09-28 12:00 |
10:04:58.42 |
-30:54:00.6 |
HIP 49450 |
10.07 |
| 2026-09-29 00:00 |
10:05:07.71 |
-30:55:58.5 |
HIP 49450 |
8.43 |
| 2026-09-29 12:00 |
10:05:16.96 |
-30:57:56.8 |
HIP 49450 |
7.53 |
| 2026-09-30 00:00 |
10:05:26.17 |
-30:59:55.5 |
HIP 49450 |
7.63 |
| 2026-09-30 12:00 |
10:05:35.33 |
-31:01:54.7 |
HIP 49450 |
8.68 |
| 2026-10-01 00:00 |
10:05:44.45 |
-31:03:54.2 |
HIP 49450 |
10.41 |
| 2026-10-01 12:00 |
10:05:53.52 |
-31:05:54.1 |
HIP 49515 |
9.83 |
| 2026-10-02 00:00 |
10:06:02.54 |
-31:07:54.4 |
HIP 49515 |
7.41 |
| 2026-10-02 12:00 |
10:06:11.52 |
-31:09:55.2 |
HIP 49515 |
5.36 |
| 2026-10-03 00:00 |
10:06:20.45 |
-31:11:56.3 |
HIP 49515 |
4.26 |
| 2026-10-03 12:00 |
10:06:29.33 |
-31:13:57.7 |
HIP 49515 |
4.80 |
| 2026-10-04 00:00 |
10:06:38.17 |
-31:15:59.6 |
HIP 49515 |
6.60 |
| 2026-10-04 12:00 |
10:06:46.95 |
-31:18:01.9 |
HIP 49515 |
8.91 |
| 2026-10-05 00:00 |
10:06:55.69 |
-31:20:04.5 |
HIP 49515 |
11.43 |
| 2026-10-05 12:00 |
10:07:04.37 |
-31:22:07.5 |
HIP 49515 |
14.05 |
| 2026-10-06 00:00 |
10:07:13.01 |
-31:24:10.8 |
HIP 49515 |
16.71 |
| 2026-10-06 12:00 |
10:07:21.59 |
-31:26:14.5 |
HIP 49515 |
19.40 |
| 2026-10-07 00:00 |
10:07:30.12 |
-31:28:18.6 |
HIP 49515 |
22.11 |
| 2026-10-07 12:00 |
10:07:38.60 |
-31:30:23.0 |
HIP 49515 |
24.82 |
| 2026-10-08 00:00 |
10:07:47.03 |
-31:32:27.8 |
HIP 49515 |
27.55 |
| 2026-10-08 12:00 |
10:07:55.41 |
-31:34:32.9 |
HIP 49647 |
29.05 |
| 2026-10-09 00:00 |
10:08:03.73 |
-31:36:38.3 |
HIP 49647 |
26.92 |
| 2026-10-09 12:00 |
10:08:11.99 |
-31:38:44.1 |
HIP 49647 |
24.92 |
| 2026-10-10 00:00 |
10:08:20.20 |
-31:40:50.2 |
HIP 49647 |
23.05 |
| 2026-10-10 12:00 |
10:08:28.36 |
-31:42:56.6 |
HIP 49647 |
21.37 |
| 2026-10-11 00:00 |
10:08:36.46 |
-31:45:03.4 |
HIP 49647 |
19.91 |