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) |
| 2026-05-12 00:00 |
04:35:35.67 |
-48:08:05.5 |
HIP 21302 |
22.68 |
| 2026-05-12 12:00 |
04:35:42.63 |
-48:07:42.0 |
HIP 21562 |
22.61 |
| 2026-05-13 00:00 |
04:35:49.62 |
-48:07:19.0 |
HIP 21562 |
21.75 |
| 2026-05-13 12:00 |
04:35:56.62 |
-48:06:56.6 |
HIP 21562 |
20.92 |
| 2026-05-14 00:00 |
04:36:03.63 |
-48:06:34.7 |
HIP 21562 |
20.13 |
| 2026-05-14 12:00 |
04:36:10.67 |
-48:06:13.3 |
HIP 21562 |
19.37 |
| 2026-05-15 00:00 |
04:36:17.72 |
-48:05:52.4 |
HIP 21562 |
18.65 |
| 2026-05-15 12:00 |
04:36:24.78 |
-48:05:32.1 |
HIP 21562 |
17.98 |
| 2026-05-16 00:00 |
04:36:31.86 |
-48:05:12.3 |
HIP 21562 |
17.37 |
| 2026-05-16 12:00 |
04:36:38.95 |
-48:04:53.0 |
HIP 21562 |
16.81 |
| 2026-05-17 00:00 |
04:36:46.06 |
-48:04:34.3 |
HIP 21562 |
16.31 |
| 2026-05-17 12:00 |
04:36:53.18 |
-48:04:16.1 |
HIP 21562 |
15.89 |
| 2026-05-18 00:00 |
04:37:00.31 |
-48:03:58.4 |
HIP 21562 |
15.54 |
| 2026-05-18 12:00 |
04:37:07.45 |
-48:03:41.3 |
HIP 21562 |
15.27 |
| 2026-05-19 00:00 |
04:37:14.61 |
-48:03:24.7 |
HIP 21562 |
15.09 |
| 2026-05-19 12:00 |
04:37:21.78 |
-48:03:08.7 |
HIP 21562 |
15.00 |
| 2026-05-20 00:00 |
04:37:28.96 |
-48:02:53.2 |
HIP 21562 |
15.00 |
| 2026-05-20 12:00 |
04:37:36.15 |
-48:02:38.2 |
HIP 21562 |
15.08 |
| 2026-05-21 00:00 |
04:37:43.35 |
-48:02:23.8 |
HIP 21562 |
15.26 |
| 2026-05-21 12:00 |
04:37:50.56 |
-48:02:09.9 |
HIP 21562 |
15.53 |
| 2026-05-22 00:00 |
04:37:57.78 |
-48:01:56.5 |
HIP 21562 |
15.87 |
| 2026-05-22 12:00 |
04:38:05.00 |
-48:01:43.7 |
HIP 21562 |
16.29 |
| 2026-05-23 00:00 |
04:38:12.24 |
-48:01:31.5 |
HIP 21562 |
16.78 |
| 2026-05-23 12:00 |
04:38:19.48 |
-48:01:19.8 |
HIP 21562 |
17.34 |
| 2026-05-24 00:00 |
04:38:26.73 |
-48:01:08.6 |
HIP 21562 |
17.95 |
| 2026-05-24 12:00 |
04:38:33.99 |
-48:00:58.0 |
HIP 21562 |
18.62 |
| 2026-05-25 00:00 |
04:38:41.25 |
-48:00:47.9 |
HIP 21562 |
19.34 |
| 2026-05-25 12:00 |
04:38:48.52 |
-48:00:38.4 |
HIP 21562 |
20.09 |
| 2026-05-26 00:00 |
04:38:55.80 |
-48:00:29.4 |
HIP 21562 |
20.89 |
| 2026-05-26 12:00 |
04:39:03.08 |
-48:00:20.9 |
HIP 21562 |
21.71 |
| 2026-05-27 00:00 |
04:39:10.37 |
-48:00:13.0 |
HIP 21562 |
22.57 |
| 2026-05-27 12:00 |
04:39:17.66 |
-48:00:05.6 |
HIP 21562 |
23.45 |
| 2026-05-28 00:00 |
04:39:24.95 |
-47:59:58.8 |
HIP 21836 |
24.35 |
| 2026-05-28 12:00 |
04:39:32.25 |
-47:59:52.5 |
HIP 21836 |
23.28 |
| 2026-05-29 00:00 |
04:39:39.55 |
-47:59:46.8 |
HIP 21836 |
22.21 |
| 2026-05-29 12:00 |
04:39:46.86 |
-47:59:41.6 |
HIP 21836 |
21.16 |
| 2026-05-30 00:00 |
04:39:54.16 |
-47:59:37.0 |
HIP 21836 |
20.12 |
| 2026-05-30 12:00 |
04:40:01.47 |
-47:59:32.9 |
HIP 21836 |
19.10 |
| 2026-05-31 00:00 |
04:40:08.78 |
-47:59:29.4 |
HIP 21836 |
18.09 |
| 2026-05-31 12:00 |
04:40:16.09 |
-47:59:26.4 |
HIP 21836 |
17.12 |
| 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 |