メタデータ
| 項目 |
値 |
| Designation |
C/2021 K1 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-05-04T13:50:34.362240Z |
| Orbit solution date (soln_date, UTC) |
2022-07-19T01:12:51Z |
| Obs used |
676 |
| NEO |
- |
| M1 |
6.600 |
| K1 |
19.000 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2021-05-24T14:32:49.718400Z |
| Discovery magnitude (MPC) |
16.39 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) |
2021-08-19.0000000 |
| e |
0.80399384 |
| q (au) |
2.497832 |
| a (au) |
12.743639 |
| i (deg) |
16.276067 |
| Ω (om, deg) |
140.905656 |
| ω (w, deg) |
184.303821 |
| M (ma, deg) |
2.305686 |
等級
散乱 + 全体線形
$$
M_a = (8.271 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
8.271 |
| n |
6.000 |
| gf |
0.800 |
| gb |
-0.840 |
| k |
0.995 |
| δ90 |
1.000 |
| 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
残差 (区間線形)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| 開始日 (UTC) |
終了日 (UTC) |
a |
b |
| 2020-04-20 |
2020-08-12 |
-4.6047 |
+5.290 |
| 2021-05-14 |
2021-11-24 |
-4.0011 |
+1.844 |
| 2021-11-24 |
2022-01-31 |
-10.7283 |
+4.958 |
log10 r = log10(太陽距離/AU)、Δ = 地球距離(AU)
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
07:20:02.79 |
+13:48:00.3 |
HIP 35501 |
10.64 |
| 2026-07-29 12:00 |
07:20:12.88 |
+13:47:39.7 |
HIP 35501 |
12.48 |
| 2026-07-30 00:00 |
07:20:22.95 |
+13:47:18.9 |
HIP 35501 |
14.50 |
| 2026-07-30 12:00 |
07:20:33.00 |
+13:46:58.0 |
HIP 35501 |
16.65 |
| 2026-07-31 00:00 |
07:20:43.03 |
+13:46:36.9 |
HIP 35501 |
18.87 |
| 2026-07-31 12:00 |
07:20:53.03 |
+13:46:15.8 |
HIP 35501 |
21.14 |
| 2026-08-01 00:00 |
07:21:03.01 |
+13:45:54.4 |
HIP 35730 |
21.97 |
| 2026-08-01 12:00 |
07:21:12.96 |
+13:45:33.0 |
HIP 35730 |
20.33 |
| 2026-08-02 00:00 |
07:21:22.89 |
+13:45:11.4 |
HIP 35730 |
18.88 |
| 2026-08-02 12:00 |
07:21:32.79 |
+13:44:49.7 |
HIP 35730 |
17.66 |
| 2026-08-03 00:00 |
07:21:42.66 |
+13:44:27.9 |
HIP 35730 |
16.70 |
| 2026-08-03 12:00 |
07:21:52.51 |
+13:44:06.0 |
HIP 35730 |
16.06 |
| 2026-08-04 00:00 |
07:22:02.33 |
+13:43:43.9 |
HIP 35760 |
14.95 |
| 2026-08-04 12:00 |
07:22:12.13 |
+13:43:21.7 |
HIP 35760 |
14.16 |
| 2026-08-05 00:00 |
07:22:21.89 |
+13:42:59.4 |
HIP 35760 |
13.75 |
| 2026-08-05 12:00 |
07:22:31.63 |
+13:42:37.0 |
HIP 35760 |
13.75 |
| 2026-08-06 00:00 |
07:22:41.34 |
+13:42:14.4 |
HIP 35760 |
14.17 |
| 2026-08-06 12:00 |
07:22:51.02 |
+13:41:51.7 |
HIP 35760 |
14.96 |
| 2026-08-07 00:00 |
07:23:00.67 |
+13:41:29.0 |
HIP 35760 |
16.06 |
| 2026-08-07 12:00 |
07:23:10.29 |
+13:41:06.1 |
HIP 35760 |
17.42 |
| 2026-08-08 00:00 |
07:23:19.88 |
+13:40:43.1 |
HIP 35760 |
18.97 |
| 2026-08-08 12:00 |
07:23:29.43 |
+13:40:20.0 |
HIP 35760 |
20.68 |
| 2026-08-09 00:00 |
07:23:38.96 |
+13:39:56.8 |
HIP 35760 |
22.50 |
| 2026-08-09 12:00 |
07:23:48.45 |
+13:39:33.4 |
HIP 35760 |
24.40 |
| 2026-08-10 00:00 |
07:23:57.91 |
+13:39:10.0 |
HIP 35760 |
26.37 |
| 2026-08-10 12:00 |
07:24:07.34 |
+13:38:46.5 |
HIP 35760 |
28.38 |
| 2026-08-11 00:00 |
07:24:16.73 |
+13:38:22.9 |
HIP 35760 |
30.44 |
| 2026-08-11 12:00 |
07:24:26.09 |
+13:37:59.1 |
HIP 35760 |
32.52 |
| 2026-08-12 00:00 |
07:24:35.41 |
+13:37:35.3 |
HIP 36153 |
33.81 |
| 2026-08-12 12:00 |
07:24:44.70 |
+13:37:11.4 |
HIP 36153 |
31.53 |
| 2026-08-13 00:00 |
07:24:53.95 |
+13:36:47.4 |
HIP 36153 |
29.25 |
| 2026-08-13 12:00 |
07:25:03.17 |
+13:36:23.3 |
HIP 36153 |
26.99 |
| 2026-08-14 00:00 |
07:25:12.35 |
+13:35:59.1 |
HIP 36153 |
24.74 |
| 2026-08-14 12:00 |
07:25:21.49 |
+13:35:34.8 |
HIP 36153 |
22.50 |
| 2026-08-15 00:00 |
07:25:30.60 |
+13:35:10.5 |
HIP 36153 |
20.27 |
| 2026-08-15 12:00 |
07:25:39.66 |
+13:34:46.0 |
HIP 36153 |
18.05 |
| 2026-08-16 00:00 |
07:25:48.69 |
+13:34:21.5 |
HIP 36153 |
15.85 |
| 2026-08-16 12:00 |
07:25:57.67 |
+13:33:56.9 |
HIP 36153 |
13.68 |
| 2026-08-17 00:00 |
07:26:06.62 |
+13:33:32.3 |
HIP 36153 |
11.52 |
| 2026-08-17 12:00 |
07:26:15.53 |
+13:33:07.5 |
HIP 36153 |
9.41 |
| 2026-08-18 00:00 |
07:26:24.40 |
+13:32:42.7 |
HIP 36153 |
7.36 |
| 2026-08-18 12:00 |
07:26:33.22 |
+13:32:17.8 |
HIP 36153 |
5.43 |
| 2026-08-19 00:00 |
07:26:42.01 |
+13:31:52.8 |
HIP 36153 |
3.81 |