メタデータ
| 項目 |
値 |
| Designation |
C/2015 ER61 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2017-05-09T22:39:09.815040Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:07Z |
| Obs used |
2826 |
| NEO |
- |
| M1 |
10.700 |
| K1 |
5.750 |
| PC |
- |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2017-04-30.0000000 |
| e |
0.99727861 |
| q (au) |
1.042132 |
| a (au) |
382.940360 |
| i (deg) |
6.348649 |
| Ω (om, deg) |
235.221741 |
| ω (w, deg) |
68.192259 |
| M (ma, deg) |
359.998692 |
等級
散乱 + 全体線形
$$
M_a = (6.321 + 4.711\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
6.321 |
| n |
4.711 |
| gf |
0.988 |
| gb |
-0.804 |
| k |
0.997 |
| δ90 |
9.892 |
| 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 |
| 2016-02-04 |
2017-05-08 |
-1.6785 |
-0.086 |
| 2017-05-13 |
2018-02-24 |
-0.6070 |
+0.658 |
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) |
| 2026-07-29 00:00 |
06:43:49.30 |
+18:47:15.7 |
HIP 32238 |
7.92 |
| 2026-07-29 12:00 |
06:43:54.08 |
+18:47:07.8 |
HIP 32238 |
7.94 |
| 2026-07-30 00:00 |
06:43:58.84 |
+18:47:00.0 |
HIP 32238 |
8.13 |
| 2026-07-30 12:00 |
06:44:03.59 |
+18:46:52.0 |
HIP 32238 |
8.45 |
| 2026-07-31 00:00 |
06:44:08.31 |
+18:46:44.1 |
HIP 32238 |
8.91 |
| 2026-07-31 12:00 |
06:44:13.02 |
+18:46:36.1 |
HIP 32238 |
9.48 |
| 2026-08-01 00:00 |
06:44:17.71 |
+18:46:28.1 |
HIP 32238 |
10.14 |
| 2026-08-01 12:00 |
06:44:22.37 |
+18:46:20.0 |
HIP 32238 |
10.86 |
| 2026-08-02 00:00 |
06:44:27.02 |
+18:46:12.0 |
HIP 32238 |
11.65 |
| 2026-08-02 12:00 |
06:44:31.65 |
+18:46:03.9 |
HIP 32238 |
12.48 |
| 2026-08-03 00:00 |
06:44:36.26 |
+18:45:55.8 |
HIP 32238 |
13.35 |
| 2026-08-03 12:00 |
06:44:40.85 |
+18:45:47.6 |
HIP 32238 |
14.24 |
| 2026-08-04 00:00 |
06:44:45.41 |
+18:45:39.5 |
HIP 32238 |
15.15 |
| 2026-08-04 12:00 |
06:44:49.96 |
+18:45:31.3 |
HIP 32238 |
16.09 |
| 2026-08-05 00:00 |
06:44:54.48 |
+18:45:23.1 |
HIP 32238 |
17.03 |
| 2026-08-05 12:00 |
06:44:58.98 |
+18:45:14.8 |
HIP 32238 |
17.99 |
| 2026-08-06 00:00 |
06:45:03.46 |
+18:45:06.6 |
HIP 32238 |
18.95 |
| 2026-08-06 12:00 |
06:45:07.92 |
+18:44:58.3 |
HIP 32451 |
18.11 |
| 2026-08-07 00:00 |
06:45:12.36 |
+18:44:50.0 |
HIP 32451 |
17.15 |
| 2026-08-07 12:00 |
06:45:16.77 |
+18:44:41.7 |
HIP 32451 |
16.21 |
| 2026-08-08 00:00 |
06:45:21.16 |
+18:44:33.4 |
HIP 32451 |
15.29 |
| 2026-08-08 12:00 |
06:45:25.53 |
+18:44:25.0 |
HIP 32451 |
14.39 |
| 2026-08-09 00:00 |
06:45:29.87 |
+18:44:16.6 |
HIP 32451 |
13.52 |
| 2026-08-09 12:00 |
06:45:34.19 |
+18:44:08.2 |
HIP 32451 |
12.68 |
| 2026-08-10 00:00 |
06:45:38.49 |
+18:43:59.8 |
HIP 32451 |
11.87 |
| 2026-08-10 12:00 |
06:45:42.76 |
+18:43:51.4 |
HIP 32451 |
11.11 |
| 2026-08-11 00:00 |
06:45:47.00 |
+18:43:43.0 |
HIP 32451 |
10.39 |
| 2026-08-11 12:00 |
06:45:51.22 |
+18:43:34.5 |
HIP 32451 |
9.73 |
| 2026-08-12 00:00 |
06:45:55.42 |
+18:43:26.0 |
HIP 32451 |
9.14 |
| 2026-08-12 12:00 |
06:45:59.59 |
+18:43:17.6 |
HIP 32451 |
8.63 |
| 2026-08-13 00:00 |
06:46:03.73 |
+18:43:09.1 |
HIP 32451 |
8.21 |
| 2026-08-13 12:00 |
06:46:07.85 |
+18:43:00.6 |
HIP 32451 |
7.90 |
| 2026-08-14 00:00 |
06:46:11.94 |
+18:42:52.0 |
HIP 32451 |
7.71 |
| 2026-08-14 12:00 |
06:46:16.00 |
+18:42:43.5 |
HIP 32451 |
7.63 |
| 2026-08-15 00:00 |
06:46:20.04 |
+18:42:35.0 |
HIP 32451 |
7.69 |
| 2026-08-15 12:00 |
06:46:24.05 |
+18:42:26.4 |
HIP 32451 |
7.85 |
| 2026-08-16 00:00 |
06:46:28.03 |
+18:42:17.8 |
HIP 32451 |
8.13 |
| 2026-08-16 12:00 |
06:46:31.98 |
+18:42:09.3 |
HIP 32451 |
8.51 |
| 2026-08-17 00:00 |
06:46:35.90 |
+18:42:00.7 |
HIP 32451 |
8.97 |
| 2026-08-17 12:00 |
06:46:39.80 |
+18:41:52.1 |
HIP 32451 |
9.49 |
| 2026-08-18 00:00 |
06:46:43.67 |
+18:41:43.5 |
HIP 32451 |
10.07 |
| 2026-08-18 12:00 |
06:46:47.51 |
+18:41:34.9 |
HIP 32451 |
10.70 |
| 2026-08-19 00:00 |
06:46:51.32 |
+18:41:26.3 |
HIP 32451 |
11.36 |