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) |
| 2026-06-01 00:00 |
04:40:23.41 |
-47:59:23.9 |
HIP 21836 |
16.16 |
| 2026-06-01 12:00 |
04:40:30.72 |
-47:59:22.0 |
HIP 21836 |
15.24 |
| 2026-06-02 00:00 |
04:40:38.03 |
-47:59:20.6 |
HIP 21836 |
14.36 |
| 2026-06-02 12:00 |
04:40:45.35 |
-47:59:19.8 |
HIP 21836 |
13.53 |
| 2026-06-03 00:00 |
04:40:52.66 |
-47:59:19.6 |
HIP 21836 |
12.75 |
| 2026-06-03 12:00 |
04:40:59.97 |
-47:59:19.9 |
HIP 21836 |
12.04 |
| 2026-06-04 00:00 |
04:41:07.28 |
-47:59:20.7 |
HIP 21836 |
11.40 |
| 2026-06-04 12:00 |
04:41:14.59 |
-47:59:22.1 |
HIP 21836 |
10.86 |
| 2026-06-05 00:00 |
04:41:21.90 |
-47:59:24.0 |
HIP 21836 |
10.43 |
| 2026-06-05 12:00 |
04:41:29.20 |
-47:59:26.5 |
HIP 21836 |
10.11 |
| 2026-06-06 00:00 |
04:41:36.50 |
-47:59:29.5 |
HIP 21836 |
9.93 |
| 2026-06-06 12:00 |
04:41:43.80 |
-47:59:33.0 |
HIP 21836 |
9.89 |
| 2026-06-07 00:00 |
04:41:51.09 |
-47:59:37.2 |
HIP 21836 |
9.98 |
| 2026-06-07 12:00 |
04:41:58.38 |
-47:59:41.8 |
HIP 21849 |
10.20 |
| 2026-06-08 00:00 |
04:42:05.66 |
-47:59:47.0 |
HIP 21849 |
10.49 |
| 2026-06-08 12:00 |
04:42:12.94 |
-47:59:52.8 |
HIP 21849 |
10.91 |
| 2026-06-09 00:00 |
04:42:20.22 |
-47:59:59.1 |
HIP 21849 |
11.46 |
| 2026-06-09 12:00 |
04:42:27.49 |
-48:00:06.0 |
HIP 21849 |
12.12 |
| 2026-06-10 00:00 |
04:42:34.75 |
-48:00:13.4 |
HIP 21849 |
12.87 |
| 2026-06-10 12:00 |
04:42:42.00 |
-48:00:21.3 |
HIP 21849 |
13.69 |
| 2026-06-11 00:00 |
04:42:49.25 |
-48:00:29.8 |
HIP 21849 |
14.57 |
| 2026-06-11 12:00 |
04:42:56.49 |
-48:00:38.9 |
HIP 21849 |
15.51 |
| 2026-06-12 00:00 |
04:43:03.72 |
-48:00:48.5 |
HIP 21849 |
16.49 |
| 2026-06-12 12:00 |
04:43:10.95 |
-48:00:58.6 |
HIP 21836 |
17.46 |
| 2026-06-13 00:00 |
04:43:18.16 |
-48:01:09.3 |
HIP 21992 |
17.38 |
| 2026-06-13 12:00 |
04:43:25.37 |
-48:01:20.6 |
HIP 21992 |
17.03 |
| 2026-06-14 00:00 |
04:43:32.56 |
-48:01:32.4 |
HIP 21992 |
16.74 |
| 2026-06-14 12:00 |
04:43:39.75 |
-48:01:44.7 |
HIP 21992 |
16.53 |
| 2026-06-15 00:00 |
04:43:46.92 |
-48:01:57.6 |
HIP 21992 |
16.40 |
| 2026-06-15 12:00 |
04:43:54.09 |
-48:02:11.1 |
HIP 21992 |
16.34 |
| 2026-06-16 00:00 |
04:44:01.24 |
-48:02:25.0 |
HIP 21992 |
16.37 |
| 2026-06-16 12:00 |
04:44:08.38 |
-48:02:39.6 |
HIP 21992 |
16.48 |
| 2026-06-17 00:00 |
04:44:15.51 |
-48:02:54.6 |
HIP 22142 |
16.47 |
| 2026-06-17 12:00 |
04:44:22.62 |
-48:03:10.3 |
HIP 22142 |
15.30 |
| 2026-06-18 00:00 |
04:44:29.72 |
-48:03:26.4 |
HIP 22142 |
14.14 |
| 2026-06-18 12:00 |
04:44:36.81 |
-48:03:43.1 |
HIP 22142 |
12.99 |
| 2026-06-19 00:00 |
04:44:43.88 |
-48:04:00.3 |
HIP 22142 |
11.86 |
| 2026-06-19 12:00 |
04:44:50.94 |
-48:04:18.1 |
HIP 22142 |
10.75 |
| 2026-06-20 00:00 |
04:44:57.98 |
-48:04:36.4 |
HIP 22142 |
9.67 |
| 2026-06-20 12:00 |
04:45:05.00 |
-48:04:55.3 |
HIP 22142 |
8.64 |
| 2026-06-21 00:00 |
04:45:12.01 |
-48:05:14.6 |
HIP 22142 |
7.67 |
| 2026-06-21 12:00 |
04:45:19.01 |
-48:05:34.6 |
HIP 22142 |
6.78 |
| 2026-06-22 00:00 |
04:45:25.98 |
-48:05:55.0 |
HIP 22142 |
6.01 |