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) |
| 2026-03-26 00:00 |
06:47:07.67 |
+13:28:23.2 |
HIP 32359 |
28.71 |
| 2026-03-26 12:00 |
06:47:08.56 |
+13:28:53.4 |
HIP 32359 |
29.06 |
| 2026-03-27 00:00 |
06:47:09.54 |
+13:29:23.4 |
HIP 32359 |
29.44 |
| 2026-03-27 12:00 |
06:47:10.61 |
+13:29:53.3 |
HIP 32687 |
29.61 |
| 2026-03-28 00:00 |
06:47:11.76 |
+13:30:23.0 |
HIP 32687 |
29.47 |
| 2026-03-28 12:00 |
06:47:13.01 |
+13:30:52.6 |
HIP 32687 |
29.33 |
| 2026-03-29 00:00 |
06:47:14.34 |
+13:31:22.0 |
HIP 32687 |
29.17 |
| 2026-03-29 12:00 |
06:47:15.75 |
+13:31:51.3 |
HIP 32687 |
29.00 |
| 2026-03-30 00:00 |
06:47:17.26 |
+13:32:20.4 |
HIP 32687 |
28.82 |
| 2026-03-30 12:00 |
06:47:18.85 |
+13:32:49.4 |
HIP 32687 |
28.64 |
| 2026-03-31 00:00 |
06:47:20.52 |
+13:33:18.2 |
HIP 32687 |
28.45 |
| 2026-03-31 12:00 |
06:47:22.29 |
+13:33:46.9 |
HIP 32687 |
28.24 |
| 2026-04-01 00:00 |
06:47:24.13 |
+13:34:15.4 |
HIP 32687 |
28.04 |
| 2026-04-01 12:00 |
06:47:26.07 |
+13:34:43.8 |
HIP 32687 |
27.82 |
| 2026-04-02 00:00 |
06:47:28.08 |
+13:35:12.0 |
HIP 32687 |
27.61 |
| 2026-04-02 12:00 |
06:47:30.19 |
+13:35:40.1 |
HIP 32687 |
27.38 |
| 2026-04-03 00:00 |
06:47:32.38 |
+13:36:08.0 |
HIP 32687 |
27.16 |
| 2026-04-03 12:00 |
06:47:34.65 |
+13:36:35.7 |
HIP 32687 |
26.93 |
| 2026-04-04 00:00 |
06:47:37.00 |
+13:37:03.3 |
HIP 32687 |
26.70 |
| 2026-04-04 12:00 |
06:47:39.45 |
+13:37:30.7 |
HIP 32687 |
26.47 |
| 2026-04-05 00:00 |
06:47:41.97 |
+13:37:57.9 |
HIP 32687 |
26.25 |
| 2026-04-05 12:00 |
06:47:44.58 |
+13:38:25.0 |
HIP 32687 |
26.02 |
| 2026-04-06 00:00 |
06:47:47.27 |
+13:38:51.9 |
HIP 32687 |
25.80 |
| 2026-04-06 12:00 |
06:47:50.04 |
+13:39:18.6 |
HIP 32687 |
25.59 |
| 2026-04-07 00:00 |
06:47:52.90 |
+13:39:45.2 |
HIP 32687 |
25.38 |
| 2026-04-07 12:00 |
06:47:55.83 |
+13:40:11.6 |
HIP 32687 |
25.19 |
| 2026-04-08 00:00 |
06:47:58.85 |
+13:40:37.8 |
HIP 32687 |
25.00 |
| 2026-04-08 12:00 |
06:48:01.96 |
+13:41:03.8 |
HIP 32687 |
24.83 |
| 2026-04-09 00:00 |
06:48:05.14 |
+13:41:29.7 |
HIP 32687 |
24.67 |
| 2026-04-09 12:00 |
06:48:08.41 |
+13:41:55.4 |
HIP 32687 |
24.53 |
| 2026-04-10 00:00 |
06:48:11.75 |
+13:42:20.9 |
HIP 32687 |
24.41 |
| 2026-04-10 12:00 |
06:48:15.18 |
+13:42:46.3 |
HIP 32687 |
24.31 |
| 2026-04-11 00:00 |
06:48:18.68 |
+13:43:11.4 |
HIP 32687 |
24.23 |
| 2026-04-11 12:00 |
06:48:22.27 |
+13:43:36.4 |
HIP 32687 |
24.18 |
| 2026-04-12 00:00 |
06:48:25.94 |
+13:44:01.2 |
HIP 32687 |
24.15 |
| 2026-04-12 12:00 |
06:48:29.68 |
+13:44:25.8 |
HIP 32687 |
24.16 |
| 2026-04-13 00:00 |
06:48:33.51 |
+13:44:50.2 |
HIP 32687 |
24.19 |
| 2026-04-13 12:00 |
06:48:37.41 |
+13:45:14.4 |
HIP 32687 |
24.26 |
| 2026-04-14 00:00 |
06:48:41.40 |
+13:45:38.4 |
HIP 32687 |
24.37 |
| 2026-04-14 12:00 |
06:48:45.46 |
+13:46:02.3 |
HIP 32687 |
24.51 |
| 2026-04-15 00:00 |
06:48:49.60 |
+13:46:25.9 |
HIP 32687 |
24.69 |
| 2026-04-15 12:00 |
06:48:53.81 |
+13:46:49.4 |
HIP 32687 |
24.91 |
| 2026-04-16 00:00 |
06:48:58.11 |
+13:47:12.6 |
HIP 32687 |
25.17 |