メタデータ
| 項目 |
値 |
| Designation |
C/2017 K4 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2018-01-08T01:00:52.058880Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:33Z |
| Obs used |
556 |
| NEO |
- |
| M1 |
4.700 |
| K1 |
19.500 |
| PC |
0.030 |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2018-03-28.0000000 |
| e |
0.90585450 |
| q (au) |
2.648085 |
| a (au) |
28.127579 |
| i (deg) |
16.678706 |
| Ω (om, deg) |
298.897270 |
| ω (w, deg) |
15.111911 |
| M (ma, deg) |
0.521675 |
等級
散乱 + 全体線形
$$
M_a = (6.069 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
6.069 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-1.000 |
| 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
残差 (区間線形)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| 開始日 (UTC) |
終了日 (UTC) |
a |
b |
| 2016-05-06 |
2017-11-12 |
+3.1769 |
-1.847 |
| 2018-04-27 |
2019-01-27 |
-4.4170 |
+2.873 |
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) |
| 2026-06-01 00:00 |
06:33:20.30 |
+28:51:37.3 |
HIP 31202 |
19.56 |
| 2026-06-01 12:00 |
06:33:27.08 |
+28:51:25.3 |
HIP 31202 |
20.35 |
| 2026-06-02 00:00 |
06:33:33.87 |
+28:51:13.4 |
HIP 31202 |
21.21 |
| 2026-06-02 12:00 |
06:33:40.69 |
+28:51:01.5 |
HIP 31202 |
22.15 |
| 2026-06-03 00:00 |
06:33:47.52 |
+28:50:49.7 |
HIP 31202 |
23.15 |
| 2026-06-03 12:00 |
06:33:54.38 |
+28:50:37.8 |
HIP 31202 |
24.20 |
| 2026-06-04 00:00 |
06:34:01.26 |
+28:50:26.0 |
HIP 31202 |
25.31 |
| 2026-06-04 12:00 |
06:34:08.15 |
+28:50:14.3 |
HIP 31202 |
26.45 |
| 2026-06-05 00:00 |
06:34:15.07 |
+28:50:02.6 |
HIP 31444 |
26.97 |
| 2026-06-05 12:00 |
06:34:22.00 |
+28:49:50.9 |
HIP 31444 |
26.08 |
| 2026-06-06 00:00 |
06:34:28.96 |
+28:49:39.2 |
HIP 31444 |
25.25 |
| 2026-06-06 12:00 |
06:34:35.93 |
+28:49:27.6 |
HIP 31544 |
24.26 |
| 2026-06-07 00:00 |
06:34:42.92 |
+28:49:16.0 |
HIP 31544 |
23.07 |
| 2026-06-07 12:00 |
06:34:49.92 |
+28:49:04.4 |
HIP 31544 |
21.91 |
| 2026-06-08 00:00 |
06:34:56.95 |
+28:48:52.9 |
HIP 31544 |
20.81 |
| 2026-06-08 12:00 |
06:35:03.99 |
+28:48:41.4 |
HIP 31544 |
19.76 |
| 2026-06-09 00:00 |
06:35:11.04 |
+28:48:30.0 |
HIP 31544 |
18.78 |
| 2026-06-09 12:00 |
06:35:18.12 |
+28:48:18.6 |
HIP 31544 |
17.87 |
| 2026-06-10 00:00 |
06:35:25.21 |
+28:48:07.2 |
HIP 31544 |
17.06 |
| 2026-06-10 12:00 |
06:35:32.31 |
+28:47:55.8 |
HIP 31544 |
16.36 |
| 2026-06-11 00:00 |
06:35:39.43 |
+28:47:44.5 |
HIP 31544 |
15.78 |
| 2026-06-11 12:00 |
06:35:46.56 |
+28:47:33.2 |
HIP 31544 |
15.33 |
| 2026-06-12 00:00 |
06:35:53.71 |
+28:47:22.0 |
HIP 31544 |
15.04 |
| 2026-06-12 12:00 |
06:36:00.87 |
+28:47:10.8 |
HIP 31544 |
14.91 |
| 2026-06-13 00:00 |
06:36:08.04 |
+28:46:59.6 |
HIP 31544 |
14.94 |
| 2026-06-13 12:00 |
06:36:15.23 |
+28:46:48.5 |
HIP 31544 |
15.14 |
| 2026-06-14 00:00 |
06:36:22.43 |
+28:46:37.4 |
HIP 31544 |
15.50 |
| 2026-06-14 12:00 |
06:36:29.64 |
+28:46:26.4 |
HIP 31544 |
16.00 |
| 2026-06-15 00:00 |
06:36:36.86 |
+28:46:15.4 |
HIP 31544 |
16.65 |
| 2026-06-15 12:00 |
06:36:44.10 |
+28:46:04.4 |
HIP 31544 |
17.42 |
| 2026-06-16 00:00 |
06:36:51.34 |
+28:45:53.5 |
HIP 31544 |
18.29 |
| 2026-06-16 12:00 |
06:36:58.60 |
+28:45:42.6 |
HIP 31544 |
19.26 |
| 2026-06-17 00:00 |
06:37:05.86 |
+28:45:31.7 |
HIP 31544 |
20.31 |
| 2026-06-17 12:00 |
06:37:13.13 |
+28:45:20.9 |
HIP 31767 |
19.35 |
| 2026-06-18 00:00 |
06:37:20.42 |
+28:45:10.1 |
HIP 31767 |
17.76 |
| 2026-06-18 12:00 |
06:37:27.71 |
+28:44:59.4 |
HIP 31767 |
16.18 |
| 2026-06-19 00:00 |
06:37:35.01 |
+28:44:48.7 |
HIP 31767 |
14.60 |
| 2026-06-19 12:00 |
06:37:42.31 |
+28:44:38.1 |
HIP 31767 |
13.02 |
| 2026-06-20 00:00 |
06:37:49.63 |
+28:44:27.4 |
HIP 31767 |
11.45 |
| 2026-06-20 12:00 |
06:37:56.95 |
+28:44:16.9 |
HIP 31767 |
9.90 |
| 2026-06-21 00:00 |
06:38:04.28 |
+28:44:06.4 |
HIP 31767 |
8.37 |
| 2026-06-21 12:00 |
06:38:11.61 |
+28:43:55.9 |
HIP 31767 |
6.87 |
| 2026-06-22 00:00 |
06:38:18.95 |
+28:43:45.4 |
HIP 31767 |
5.45 |