メタデータ
| 項目 |
値 |
| Designation |
C/2015 X8 (NEOWISE) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-10-23T02:58:51.087360Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:20Z |
| Obs used |
116 |
| NEO |
Yes |
| M1 |
16.200 |
| K1 |
4.500 |
| PC |
0.030 |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2016-01-22.0000000 |
| e |
0.93911400 |
| q (au) |
1.190273 |
| a (au) |
19.549200 |
| i (deg) |
155.281698 |
| Ω (om, deg) |
191.111870 |
| ω (w, deg) |
20.400527 |
| M (ma, deg) |
1.036236 |
等級
散乱 + 全体線形
$$
M_a = (15.395 + 4.524\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
15.395 |
| n |
4.524 |
| gf |
0.999 |
| gb |
-0.984 |
| k |
0.971 |
| 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
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
00:33:34.41 |
+02:30:50.4 |
HIP 2703 |
12.55 |
| 2026-03-26 12:00 |
00:33:38.95 |
+02:31:17.2 |
HIP 2703 |
11.62 |
| 2026-03-27 00:00 |
00:33:43.50 |
+02:31:43.9 |
HIP 2703 |
10.74 |
| 2026-03-27 12:00 |
00:33:48.04 |
+02:32:10.7 |
HIP 2703 |
9.93 |
| 2026-03-28 00:00 |
00:33:52.59 |
+02:32:37.4 |
HIP 2703 |
9.22 |
| 2026-03-28 12:00 |
00:33:57.14 |
+02:33:04.2 |
HIP 2703 |
8.62 |
| 2026-03-29 00:00 |
00:34:01.69 |
+02:33:30.9 |
HIP 2703 |
8.16 |
| 2026-03-29 12:00 |
00:34:06.24 |
+02:33:57.6 |
HIP 2703 |
7.86 |
| 2026-03-30 00:00 |
00:34:10.79 |
+02:34:24.3 |
HIP 2703 |
7.75 |
| 2026-03-30 12:00 |
00:34:15.34 |
+02:34:51.0 |
HIP 2703 |
7.82 |
| 2026-03-31 00:00 |
00:34:19.89 |
+02:35:17.7 |
HIP 2703 |
8.09 |
| 2026-03-31 12:00 |
00:34:24.43 |
+02:35:44.3 |
HIP 2703 |
8.52 |
| 2026-04-01 00:00 |
00:34:28.98 |
+02:36:10.9 |
HIP 2703 |
9.09 |
| 2026-04-01 12:00 |
00:34:33.52 |
+02:36:37.5 |
HIP 2703 |
9.78 |
| 2026-04-02 00:00 |
00:34:38.06 |
+02:37:04.1 |
HIP 2703 |
10.57 |
| 2026-04-02 12:00 |
00:34:42.60 |
+02:37:30.6 |
HIP 2703 |
11.43 |
| 2026-04-03 00:00 |
00:34:47.14 |
+02:37:57.1 |
HIP 2703 |
12.35 |
| 2026-04-03 12:00 |
00:34:51.67 |
+02:38:23.6 |
HIP 2703 |
13.32 |
| 2026-04-04 00:00 |
00:34:56.21 |
+02:38:50.1 |
HIP 2703 |
14.33 |
| 2026-04-04 12:00 |
00:35:00.73 |
+02:39:16.5 |
HIP 2703 |
15.36 |
| 2026-04-05 00:00 |
00:35:05.26 |
+02:39:42.9 |
HIP 2703 |
16.42 |
| 2026-04-05 12:00 |
00:35:09.78 |
+02:40:09.2 |
HIP 2703 |
17.50 |
| 2026-04-06 00:00 |
00:35:14.29 |
+02:40:35.5 |
HIP 2703 |
18.59 |
| 2026-04-06 12:00 |
00:35:18.80 |
+02:41:01.7 |
HIP 2703 |
19.69 |
| 2026-04-07 00:00 |
00:35:23.31 |
+02:41:27.9 |
HIP 2703 |
20.81 |
| 2026-04-07 12:00 |
00:35:27.81 |
+02:41:54.1 |
HIP 2703 |
21.93 |
| 2026-04-08 00:00 |
00:35:32.31 |
+02:42:20.2 |
HIP 2703 |
23.06 |
| 2026-04-08 12:00 |
00:35:36.80 |
+02:42:46.2 |
HIP 2703 |
24.19 |
| 2026-04-09 00:00 |
00:35:41.28 |
+02:43:12.2 |
HIP 2703 |
25.33 |
| 2026-04-09 12:00 |
00:35:45.76 |
+02:43:38.2 |
HIP 2703 |
26.48 |
| 2026-04-10 00:00 |
00:35:50.23 |
+02:44:04.1 |
HIP 2703 |
27.62 |
| 2026-04-10 12:00 |
00:35:54.69 |
+02:44:29.9 |
HIP 2703 |
28.77 |
| 2026-04-11 00:00 |
00:35:59.15 |
+02:44:55.7 |
HIP 2759 |
29.90 |
| 2026-04-11 12:00 |
00:36:03.60 |
+02:45:21.4 |
HIP 2988 |
29.21 |
| 2026-04-12 00:00 |
00:36:08.04 |
+02:45:47.1 |
HIP 2988 |
28.09 |
| 2026-04-12 12:00 |
00:36:12.47 |
+02:46:12.6 |
HIP 2988 |
26.99 |
| 2026-04-13 00:00 |
00:36:16.90 |
+02:46:38.1 |
HIP 2988 |
25.89 |
| 2026-04-13 12:00 |
00:36:21.31 |
+02:47:03.6 |
HIP 2988 |
24.81 |
| 2026-04-14 00:00 |
00:36:25.72 |
+02:47:29.0 |
HIP 2988 |
23.74 |
| 2026-04-14 12:00 |
00:36:30.11 |
+02:47:54.2 |
HIP 2988 |
22.68 |
| 2026-04-15 00:00 |
00:36:34.50 |
+02:48:19.5 |
HIP 2988 |
21.63 |
| 2026-04-15 12:00 |
00:36:38.88 |
+02:48:44.6 |
HIP 2988 |
20.60 |
| 2026-04-16 00:00 |
00:36:43.25 |
+02:49:09.7 |
HIP 2988 |
19.59 |