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) |
| 2026-09-20 00:00 |
07:34:19.09 |
+13:04:20.1 |
HIP 36709 |
19.76 |
| 2026-09-20 12:00 |
07:34:24.30 |
+13:03:54.9 |
HIP 36709 |
21.09 |
| 2026-09-21 00:00 |
07:34:29.43 |
+13:03:29.8 |
HIP 36709 |
22.41 |
| 2026-09-21 12:00 |
07:34:34.50 |
+13:03:04.8 |
HIP 36709 |
23.71 |
| 2026-09-22 00:00 |
07:34:39.50 |
+13:02:39.8 |
HIP 36709 |
25.00 |
| 2026-09-22 12:00 |
07:34:44.43 |
+13:02:14.8 |
HIP 36771 |
26.22 |
| 2026-09-23 00:00 |
07:34:49.29 |
+13:01:50.0 |
HIP 36771 |
27.21 |
| 2026-09-23 12:00 |
07:34:54.08 |
+13:01:25.2 |
HIP 36771 |
28.21 |
| 2026-09-24 00:00 |
07:34:58.80 |
+13:01:00.6 |
HIP 37045 |
27.65 |
| 2026-09-24 12:00 |
07:35:03.46 |
+13:00:36.0 |
HIP 37045 |
26.45 |
| 2026-09-25 00:00 |
07:35:08.04 |
+13:00:11.4 |
HIP 37045 |
25.26 |
| 2026-09-25 12:00 |
07:35:12.55 |
+12:59:47.0 |
HIP 37045 |
24.09 |
| 2026-09-26 00:00 |
07:35:16.99 |
+12:59:22.7 |
HIP 37045 |
22.93 |
| 2026-09-26 12:00 |
07:35:21.36 |
+12:58:58.4 |
HIP 37045 |
21.79 |
| 2026-09-27 00:00 |
07:35:25.65 |
+12:58:34.3 |
HIP 37045 |
20.67 |
| 2026-09-27 12:00 |
07:35:29.88 |
+12:58:10.2 |
HIP 37045 |
19.57 |
| 2026-09-28 00:00 |
07:35:34.03 |
+12:57:46.2 |
HIP 37045 |
18.48 |
| 2026-09-28 12:00 |
07:35:38.11 |
+12:57:22.4 |
HIP 37045 |
17.41 |
| 2026-09-29 00:00 |
07:35:42.12 |
+12:56:58.6 |
HIP 37045 |
16.36 |
| 2026-09-29 12:00 |
07:35:46.06 |
+12:56:34.9 |
HIP 37045 |
15.33 |
| 2026-09-30 00:00 |
07:35:49.92 |
+12:56:11.4 |
HIP 37045 |
14.31 |
| 2026-09-30 12:00 |
07:35:53.71 |
+12:55:47.9 |
HIP 37045 |
13.32 |
| 2026-10-01 00:00 |
07:35:57.43 |
+12:55:24.6 |
HIP 37045 |
12.34 |
| 2026-10-01 12:00 |
07:36:01.07 |
+12:55:01.3 |
HIP 37045 |
11.38 |
| 2026-10-02 00:00 |
07:36:04.63 |
+12:54:38.2 |
HIP 37045 |
10.44 |
| 2026-10-02 12:00 |
07:36:08.12 |
+12:54:15.2 |
HIP 37045 |
9.52 |
| 2026-10-03 00:00 |
07:36:11.54 |
+12:53:52.3 |
HIP 37045 |
8.62 |
| 2026-10-03 12:00 |
07:36:14.88 |
+12:53:29.5 |
HIP 37045 |
7.74 |
| 2026-10-04 00:00 |
07:36:18.15 |
+12:53:06.9 |
HIP 37045 |
6.89 |
| 2026-10-04 12:00 |
07:36:21.34 |
+12:52:44.3 |
HIP 37045 |
6.06 |
| 2026-10-05 00:00 |
07:36:24.45 |
+12:52:21.9 |
HIP 37045 |
5.27 |
| 2026-10-05 12:00 |
07:36:27.48 |
+12:51:59.7 |
HIP 37045 |
4.51 |
| 2026-10-06 00:00 |
07:36:30.44 |
+12:51:37.5 |
HIP 37045 |
3.80 |
| 2026-10-06 12:00 |
07:36:33.32 |
+12:51:15.5 |
HIP 37045 |
3.16 |
| 2026-10-07 00:00 |
07:36:36.13 |
+12:50:53.7 |
HIP 37045 |
2.62 |
| 2026-10-07 12:00 |
07:36:38.86 |
+12:50:31.9 |
HIP 37045 |
2.23 |
| 2026-10-08 00:00 |
07:36:41.50 |
+12:50:10.4 |
HIP 37045 |
2.07 |
| 2026-10-08 12:00 |
07:36:44.07 |
+12:49:48.9 |
HIP 37045 |
2.17 |
| 2026-10-09 00:00 |
07:36:46.56 |
+12:49:27.6 |
HIP 37045 |
2.48 |
| 2026-10-09 12:00 |
07:36:48.98 |
+12:49:06.5 |
HIP 37045 |
2.92 |
| 2026-10-10 00:00 |
07:36:51.31 |
+12:48:45.5 |
HIP 37045 |
3.43 |
| 2026-10-10 12:00 |
07:36:53.56 |
+12:48:24.6 |
HIP 37045 |
3.97 |
| 2026-10-11 00:00 |
07:36:55.74 |
+12:48:03.9 |
HIP 37045 |
4.54 |