メタデータ
| 項目 |
値 |
| Designation |
C/2017 E4 (Lovejoy) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-04-23T07:32:57.215040Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:31Z |
| Obs used |
642 |
| NEO |
- |
| M1 |
15.600 |
| K1 |
29.750 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2017-03-31.0000000 |
| e |
0.99896241 |
| q (au) |
0.493573 |
| a (au) |
475.690786 |
| i (deg) |
88.186837 |
| Ω (om, deg) |
223.171811 |
| ω (w, deg) |
87.244054 |
| M (ma, deg) |
359.997785 |
等級
散乱 + 全体線形
$$
M_a = (15.265 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
15.265 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| 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 |
| 2017-03-09 |
2017-03-27 |
+15.0652 |
-0.620 |
| 2017-03-27 |
2017-04-23 |
-14.4941 |
-4.028 |
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 |
04:55:52.22 |
-50:53:03.2 |
HIP 22953 |
10.59 |
| 2026-09-20 12:00 |
04:55:50.63 |
-50:54:14.6 |
HIP 22953 |
9.62 |
| 2026-09-21 00:00 |
04:55:48.97 |
-50:55:25.9 |
HIP 22953 |
8.71 |
| 2026-09-21 12:00 |
04:55:47.24 |
-50:56:37.0 |
HIP 22953 |
7.89 |
| 2026-09-22 00:00 |
04:55:45.45 |
-50:57:48.1 |
HIP 22953 |
7.19 |
| 2026-09-22 12:00 |
04:55:43.59 |
-50:58:59.0 |
HIP 22953 |
6.66 |
| 2026-09-23 00:00 |
04:55:41.67 |
-51:00:09.8 |
HIP 22953 |
6.33 |
| 2026-09-23 12:00 |
04:55:39.68 |
-51:01:20.4 |
HIP 22953 |
6.23 |
| 2026-09-24 00:00 |
04:55:37.63 |
-51:02:30.9 |
HIP 22953 |
6.38 |
| 2026-09-24 12:00 |
04:55:35.51 |
-51:03:41.3 |
HIP 22953 |
6.75 |
| 2026-09-25 00:00 |
04:55:33.33 |
-51:04:51.5 |
HIP 22953 |
7.33 |
| 2026-09-25 12:00 |
04:55:31.08 |
-51:06:01.5 |
HIP 22953 |
8.05 |
| 2026-09-26 00:00 |
04:55:28.76 |
-51:07:11.4 |
HIP 22816 |
8.83 |
| 2026-09-26 12:00 |
04:55:26.39 |
-51:08:21.1 |
HIP 22816 |
8.70 |
| 2026-09-27 00:00 |
04:55:23.94 |
-51:09:30.6 |
HIP 22816 |
8.74 |
| 2026-09-27 12:00 |
04:55:21.43 |
-51:10:40.0 |
HIP 22816 |
8.93 |
| 2026-09-28 00:00 |
04:55:18.86 |
-51:11:49.2 |
HIP 22816 |
9.27 |
| 2026-09-28 12:00 |
04:55:16.23 |
-51:12:58.2 |
HIP 22816 |
9.75 |
| 2026-09-29 00:00 |
04:55:13.52 |
-51:14:07.0 |
HIP 22816 |
10.34 |
| 2026-09-29 12:00 |
04:55:10.76 |
-51:15:15.6 |
HIP 22816 |
11.03 |
| 2026-09-30 00:00 |
04:55:07.93 |
-51:16:24.0 |
HIP 22816 |
11.79 |
| 2026-09-30 12:00 |
04:55:05.04 |
-51:17:32.2 |
HIP 22816 |
12.62 |
| 2026-10-01 00:00 |
04:55:02.08 |
-51:18:40.2 |
HIP 22816 |
13.51 |
| 2026-10-01 12:00 |
04:54:59.05 |
-51:19:47.9 |
HIP 22816 |
14.44 |
| 2026-10-02 00:00 |
04:54:55.97 |
-51:20:55.5 |
HIP 22816 |
15.40 |
| 2026-10-02 12:00 |
04:54:52.82 |
-51:22:02.8 |
HIP 22816 |
16.39 |
| 2026-10-03 00:00 |
04:54:49.61 |
-51:23:09.9 |
HIP 22816 |
17.41 |
| 2026-10-03 12:00 |
04:54:46.33 |
-51:24:16.7 |
HIP 22975 |
17.75 |
| 2026-10-04 00:00 |
04:54:42.99 |
-51:25:23.3 |
HIP 22975 |
18.12 |
| 2026-10-04 12:00 |
04:54:39.58 |
-51:26:29.7 |
HIP 22975 |
18.58 |
| 2026-10-05 00:00 |
04:54:36.12 |
-51:27:35.8 |
HIP 22975 |
19.11 |
| 2026-10-05 12:00 |
04:54:32.59 |
-51:28:41.6 |
HIP 22975 |
19.71 |
| 2026-10-06 00:00 |
04:54:28.99 |
-51:29:47.2 |
HIP 22975 |
20.38 |
| 2026-10-06 12:00 |
04:54:25.34 |
-51:30:52.5 |
HIP 22975 |
21.10 |
| 2026-10-07 00:00 |
04:54:21.62 |
-51:31:57.5 |
HIP 22975 |
21.88 |
| 2026-10-07 12:00 |
04:54:17.84 |
-51:33:02.2 |
HIP 22975 |
22.71 |
| 2026-10-08 00:00 |
04:54:14.00 |
-51:34:06.7 |
HIP 22975 |
23.58 |
| 2026-10-08 12:00 |
04:54:10.09 |
-51:35:10.8 |
HIP 22975 |
24.49 |
| 2026-10-09 00:00 |
04:54:06.13 |
-51:36:14.7 |
HIP 22975 |
25.43 |
| 2026-10-09 12:00 |
04:54:02.10 |
-51:37:18.2 |
HIP 22570 |
24.84 |
| 2026-10-10 00:00 |
04:53:58.01 |
-51:38:21.4 |
HIP 22570 |
23.97 |
| 2026-10-10 12:00 |
04:53:53.86 |
-51:39:24.4 |
HIP 22570 |
23.13 |
| 2026-10-11 00:00 |
04:53:49.66 |
-51:40:26.9 |
HIP 22570 |
22.31 |