メタデータ
| 項目 |
値 |
| Designation |
C/2015 YG1 (NEOWISE) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2015-09-28T23:19:05.626560Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:33:21Z |
| Obs used |
222 |
| NEO |
- |
| M1 |
12.100 |
| K1 |
10.500 |
| PC |
0.030 |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2016-02-05.0000000 |
| e |
0.87923622 |
| q (au) |
2.073411 |
| a (au) |
17.169149 |
| i (deg) |
57.336038 |
| Ω (om, deg) |
350.511863 |
| ω (w, deg) |
102.791763 |
| M (ma, deg) |
1.787583 |
等級
散乱 + 全体線形
$$
M_a = (H_0 + n\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
- |
| n |
- |
| gf |
- |
| gb |
- |
| k |
- |
| δ90 |
- |
| 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 |
13:09:53.05 |
-72:23:44.9 |
HIP 64501 |
17.56 |
| 2026-07-29 12:00 |
13:09:59.16 |
-72:22:42.7 |
HIP 64501 |
17.73 |
| 2026-07-30 00:00 |
13:10:05.40 |
-72:21:40.8 |
HIP 64501 |
17.96 |
| 2026-07-30 12:00 |
13:10:11.77 |
-72:20:39.3 |
HIP 64501 |
18.25 |
| 2026-07-31 00:00 |
13:10:18.25 |
-72:19:38.1 |
HIP 64501 |
18.58 |
| 2026-07-31 12:00 |
13:10:24.86 |
-72:18:37.3 |
HIP 64501 |
18.97 |
| 2026-08-01 00:00 |
13:10:31.59 |
-72:17:36.8 |
HIP 64501 |
19.41 |
| 2026-08-01 12:00 |
13:10:38.45 |
-72:16:36.6 |
HIP 64501 |
19.88 |
| 2026-08-02 00:00 |
13:10:45.42 |
-72:15:36.8 |
HIP 64501 |
20.40 |
| 2026-08-02 12:00 |
13:10:52.51 |
-72:14:37.3 |
HIP 64501 |
20.96 |
| 2026-08-03 00:00 |
13:10:59.73 |
-72:13:38.2 |
HIP 64501 |
21.55 |
| 2026-08-03 12:00 |
13:11:07.06 |
-72:12:39.4 |
HIP 64501 |
22.18 |
| 2026-08-04 00:00 |
13:11:14.51 |
-72:11:41.0 |
HIP 64501 |
22.83 |
| 2026-08-04 12:00 |
13:11:22.07 |
-72:10:43.0 |
HIP 64331 |
21.89 |
| 2026-08-05 00:00 |
13:11:29.76 |
-72:09:45.3 |
HIP 64331 |
20.97 |
| 2026-08-05 12:00 |
13:11:37.56 |
-72:08:48.0 |
HIP 64331 |
20.08 |
| 2026-08-06 00:00 |
13:11:45.47 |
-72:07:51.1 |
HIP 64331 |
19.22 |
| 2026-08-06 12:00 |
13:11:53.50 |
-72:06:54.6 |
HIP 64331 |
18.40 |
| 2026-08-07 00:00 |
13:12:01.65 |
-72:05:58.4 |
HIP 64331 |
17.62 |
| 2026-08-07 12:00 |
13:12:09.91 |
-72:05:02.6 |
HIP 64555 |
16.57 |
| 2026-08-08 00:00 |
13:12:18.28 |
-72:04:07.2 |
HIP 64555 |
15.45 |
| 2026-08-08 12:00 |
13:12:26.76 |
-72:03:12.3 |
HIP 64555 |
14.33 |
| 2026-08-09 00:00 |
13:12:35.35 |
-72:02:17.7 |
HIP 64555 |
13.22 |
| 2026-08-09 12:00 |
13:12:44.06 |
-72:01:23.5 |
HIP 64555 |
12.11 |
| 2026-08-10 00:00 |
13:12:52.87 |
-72:00:29.7 |
HIP 64555 |
11.00 |
| 2026-08-10 12:00 |
13:13:01.80 |
-71:59:36.3 |
HIP 64555 |
9.90 |
| 2026-08-11 00:00 |
13:13:10.83 |
-71:58:43.3 |
HIP 64555 |
8.80 |
| 2026-08-11 12:00 |
13:13:19.97 |
-71:57:50.8 |
HIP 64555 |
7.72 |
| 2026-08-12 00:00 |
13:13:29.22 |
-71:56:58.7 |
HIP 64555 |
6.66 |
| 2026-08-12 12:00 |
13:13:38.57 |
-71:56:07.0 |
HIP 64555 |
5.64 |
| 2026-08-13 00:00 |
13:13:48.03 |
-71:55:15.7 |
HIP 64555 |
4.66 |
| 2026-08-13 12:00 |
13:13:57.60 |
-71:54:24.8 |
HIP 64555 |
3.77 |
| 2026-08-14 00:00 |
13:14:07.27 |
-71:53:34.4 |
HIP 64555 |
3.06 |
| 2026-08-14 12:00 |
13:14:17.04 |
-71:52:44.4 |
HIP 64555 |
2.66 |
| 2026-08-15 00:00 |
13:14:26.91 |
-71:51:54.9 |
HIP 64555 |
2.72 |
| 2026-08-15 12:00 |
13:14:36.89 |
-71:51:05.8 |
HIP 64555 |
3.22 |
| 2026-08-16 00:00 |
13:14:46.97 |
-71:50:17.1 |
HIP 64555 |
3.99 |
| 2026-08-16 12:00 |
13:14:57.14 |
-71:49:28.9 |
HIP 64555 |
4.91 |
| 2026-08-17 00:00 |
13:15:07.42 |
-71:48:41.1 |
HIP 64555 |
5.91 |
| 2026-08-17 12:00 |
13:15:17.79 |
-71:47:53.8 |
HIP 64555 |
6.95 |
| 2026-08-18 00:00 |
13:15:28.26 |
-71:47:07.0 |
HIP 64555 |
8.02 |
| 2026-08-18 12:00 |
13:15:38.83 |
-71:46:20.6 |
HIP 64555 |
9.11 |
| 2026-08-19 00:00 |
13:15:49.49 |
-71:45:34.6 |
HIP 64555 |
10.21 |