C/2017 K4 (ATLAS)
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) |
| 2026-02-03 00:00 |
06:28:00.02 |
+29:40:06.3 |
HIP 30738 |
6.60 |
| 2026-02-03 12:00 |
06:27:54.73 |
+29:39:59.3 |
HIP 30738 |
5.46 |
| 2026-02-04 00:00 |
06:27:49.49 |
+29:39:52.3 |
HIP 30738 |
4.34 |
| 2026-02-04 12:00 |
06:27:44.29 |
+29:39:45.1 |
HIP 30738 |
3.23 |
| 2026-02-05 00:00 |
06:27:39.15 |
+29:39:37.8 |
HIP 30738 |
2.17 |
| 2026-02-05 12:00 |
06:27:34.05 |
+29:39:30.4 |
HIP 30738 |
1.24 |
| 2026-02-06 00:00 |
06:27:29.00 |
+29:39:22.9 |
HIP 30738 |
0.91 |
| 2026-02-06 12:00 |
06:27:24.00 |
+29:39:15.3 |
HIP 30738 |
1.59 |
| 2026-02-07 00:00 |
06:27:19.04 |
+29:39:07.5 |
HIP 30738 |
2.56 |
| 2026-02-07 12:00 |
06:27:14.14 |
+29:38:59.7 |
HIP 30738 |
3.59 |
| 2026-02-08 00:00 |
06:27:09.28 |
+29:38:51.8 |
HIP 30738 |
4.62 |
| 2026-02-08 12:00 |
06:27:04.48 |
+29:38:43.8 |
HIP 30738 |
5.66 |
| 2026-02-09 00:00 |
06:26:59.73 |
+29:38:35.6 |
HIP 30738 |
6.69 |
| 2026-02-09 12:00 |
06:26:55.03 |
+29:38:27.4 |
HIP 30639 |
7.55 |
| 2026-02-10 00:00 |
06:26:50.38 |
+29:38:19.0 |
HIP 30639 |
6.53 |
| 2026-02-10 12:00 |
06:26:45.78 |
+29:38:10.6 |
HIP 30639 |
5.53 |
| 2026-02-11 00:00 |
06:26:41.23 |
+29:38:02.1 |
HIP 30639 |
4.53 |
| 2026-02-11 12:00 |
06:26:36.74 |
+29:37:53.4 |
HIP 30639 |
3.55 |
| 2026-02-12 00:00 |
06:26:32.30 |
+29:37:44.7 |
HIP 30639 |
2.59 |
| 2026-02-12 12:00 |
06:26:27.91 |
+29:37:35.8 |
HIP 30639 |
1.65 |
| 2026-02-13 00:00 |
06:26:23.58 |
+29:37:26.9 |
HIP 30639 |
0.80 |
| 2026-02-13 12:00 |
06:26:19.31 |
+29:37:17.9 |
HIP 30639 |
0.59 |
| 2026-02-14 00:00 |
06:26:15.08 |
+29:37:08.8 |
HIP 30639 |
1.35 |
| 2026-02-14 12:00 |
06:26:10.92 |
+29:36:59.5 |
HIP 30639 |
2.23 |
| 2026-02-15 00:00 |
06:26:06.80 |
+29:36:50.2 |
HIP 30639 |
3.12 |
| 2026-02-15 12:00 |
06:26:02.75 |
+29:36:40.8 |
HIP 30639 |
4.00 |
| 2026-02-16 00:00 |
06:25:58.75 |
+29:36:31.4 |
HIP 30639 |
4.88 |
| 2026-02-16 12:00 |
06:25:54.81 |
+29:36:21.8 |
HIP 30639 |
5.75 |
| 2026-02-17 00:00 |
06:25:50.92 |
+29:36:12.1 |
HIP 30561 |
5.50 |
| 2026-02-17 12:00 |
06:25:47.09 |
+29:36:02.4 |
HIP 30561 |
4.67 |
| 2026-02-18 00:00 |
06:25:43.32 |
+29:35:52.5 |
HIP 30561 |
3.85 |
| 2026-02-18 12:00 |
06:25:39.61 |
+29:35:42.6 |
HIP 30561 |
3.05 |
| 2026-02-19 00:00 |
06:25:35.95 |
+29:35:32.6 |
HIP 30561 |
2.28 |
| 2026-02-19 12:00 |
06:25:32.36 |
+29:35:22.5 |
HIP 30561 |
1.57 |
| 2026-02-20 00:00 |
06:25:28.82 |
+29:35:12.3 |
HIP 30561 |
1.00 |
| 2026-02-20 12:00 |
06:25:25.34 |
+29:35:02.0 |
HIP 30561 |
0.87 |
| 2026-02-21 00:00 |
06:25:21.92 |
+29:34:51.7 |
HIP 30561 |
1.30 |
| 2026-02-21 12:00 |
06:25:18.56 |
+29:34:41.3 |
HIP 30561 |
1.93 |
| 2026-02-22 00:00 |
06:25:15.26 |
+29:34:30.8 |
HIP 30561 |
2.61 |
| 2026-02-22 12:00 |
06:25:12.02 |
+29:34:20.2 |
HIP 30561 |
3.31 |
| 2026-02-23 00:00 |
06:25:08.84 |
+29:34:09.5 |
HIP 30561 |
4.00 |
| 2026-02-23 12:00 |
06:25:05.73 |
+29:33:58.8 |
HIP 30561 |
4.68 |
| 2026-02-24 00:00 |
06:25:02.67 |
+29:33:48.0 |
HIP 30561 |
5.36 |