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) |
| 2026-07-29 00:00 |
00:42:04.45 |
+03:09:52.5 |
HIP 3276 |
29.05 |
| 2026-07-29 12:00 |
00:42:02.08 |
+03:09:33.2 |
HIP 3276 |
29.28 |
| 2026-07-30 00:00 |
00:41:59.68 |
+03:09:13.6 |
HIP 3276 |
29.53 |
| 2026-07-30 12:00 |
00:41:57.24 |
+03:08:53.8 |
HIP 3276 |
29.80 |
| 2026-07-31 00:00 |
00:41:54.76 |
+03:08:33.7 |
HIP 3276 |
30.08 |
| 2026-07-31 12:00 |
00:41:52.24 |
+03:08:13.4 |
HIP 3276 |
30.38 |
| 2026-08-01 00:00 |
00:41:49.68 |
+03:07:52.9 |
HIP 3276 |
30.69 |
| 2026-08-01 12:00 |
00:41:47.09 |
+03:07:32.1 |
HIP 3276 |
31.03 |
| 2026-08-02 00:00 |
00:41:44.45 |
+03:07:11.1 |
HIP 3276 |
31.38 |
| 2026-08-02 12:00 |
00:41:41.78 |
+03:06:49.8 |
HIP 3276 |
31.75 |
| 2026-08-03 00:00 |
00:41:39.06 |
+03:06:28.3 |
HIP 3276 |
32.14 |
| 2026-08-03 12:00 |
00:41:36.31 |
+03:06:06.6 |
HIP 3276 |
32.54 |
| 2026-08-04 00:00 |
00:41:33.52 |
+03:05:44.6 |
HIP 3276 |
32.97 |
| 2026-08-04 12:00 |
00:41:30.70 |
+03:05:22.4 |
HIP 3276 |
33.41 |
| 2026-08-05 00:00 |
00:41:27.83 |
+03:05:00.0 |
HIP 3086 |
33.84 |
| 2026-08-05 12:00 |
00:41:24.93 |
+03:04:37.3 |
HIP 3086 |
33.15 |
| 2026-08-06 00:00 |
00:41:21.99 |
+03:04:14.4 |
HIP 3086 |
32.47 |
| 2026-08-06 12:00 |
00:41:19.02 |
+03:03:51.2 |
HIP 3086 |
31.78 |
| 2026-08-07 00:00 |
00:41:16.00 |
+03:03:27.8 |
HIP 3086 |
31.09 |
| 2026-08-07 12:00 |
00:41:12.95 |
+03:03:04.2 |
HIP 3086 |
30.39 |
| 2026-08-08 00:00 |
00:41:09.86 |
+03:02:40.4 |
HIP 3086 |
29.70 |
| 2026-08-08 12:00 |
00:41:06.74 |
+03:02:16.3 |
HIP 3086 |
29.01 |
| 2026-08-09 00:00 |
00:41:03.57 |
+03:01:52.0 |
HIP 3086 |
28.32 |
| 2026-08-09 12:00 |
00:41:00.38 |
+03:01:27.5 |
HIP 3086 |
27.64 |
| 2026-08-10 00:00 |
00:40:57.14 |
+03:01:02.7 |
HIP 3086 |
26.96 |
| 2026-08-10 12:00 |
00:40:53.87 |
+03:00:37.7 |
HIP 3086 |
26.28 |
| 2026-08-11 00:00 |
00:40:50.56 |
+03:00:12.5 |
HIP 3086 |
25.62 |
| 2026-08-11 12:00 |
00:40:47.22 |
+02:59:47.1 |
HIP 3086 |
24.96 |
| 2026-08-12 00:00 |
00:40:43.84 |
+02:59:21.5 |
HIP 3086 |
24.31 |
| 2026-08-12 12:00 |
00:40:40.43 |
+02:58:55.6 |
HIP 3086 |
23.68 |
| 2026-08-13 00:00 |
00:40:36.98 |
+02:58:29.6 |
HIP 3086 |
23.06 |
| 2026-08-13 12:00 |
00:40:33.50 |
+02:58:03.3 |
HIP 3086 |
22.46 |
| 2026-08-14 00:00 |
00:40:29.98 |
+02:57:36.8 |
HIP 3086 |
21.88 |
| 2026-08-14 12:00 |
00:40:26.43 |
+02:57:10.1 |
HIP 3086 |
21.33 |
| 2026-08-15 00:00 |
00:40:22.85 |
+02:56:43.2 |
HIP 3086 |
20.80 |
| 2026-08-15 12:00 |
00:40:19.23 |
+02:56:16.1 |
HIP 3086 |
20.31 |
| 2026-08-16 00:00 |
00:40:15.57 |
+02:55:48.7 |
HIP 3086 |
19.85 |
| 2026-08-16 12:00 |
00:40:11.89 |
+02:55:21.2 |
HIP 3086 |
19.42 |
| 2026-08-17 00:00 |
00:40:08.17 |
+02:54:53.5 |
HIP 3086 |
19.04 |
| 2026-08-17 12:00 |
00:40:04.42 |
+02:54:25.6 |
HIP 3086 |
18.71 |
| 2026-08-18 00:00 |
00:40:00.63 |
+02:53:57.4 |
HIP 3086 |
18.43 |
| 2026-08-18 12:00 |
00:39:56.81 |
+02:53:29.1 |
HIP 3086 |
18.20 |
| 2026-08-19 00:00 |
00:39:52.97 |
+02:53:00.6 |
HIP 3086 |
18.03 |