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) |
| 2026-03-26 00:00 |
13:56:06.75 |
-75:23:36.5 |
HIP 67698 |
15.81 |
| 2026-03-26 12:00 |
13:55:48.45 |
-75:24:06.0 |
HIP 67698 |
14.58 |
| 2026-03-27 00:00 |
13:55:30.04 |
-75:24:34.9 |
HIP 67698 |
13.34 |
| 2026-03-27 12:00 |
13:55:11.53 |
-75:25:02.9 |
HIP 67698 |
12.11 |
| 2026-03-28 00:00 |
13:54:52.92 |
-75:25:30.2 |
HIP 67698 |
10.88 |
| 2026-03-28 12:00 |
13:54:34.20 |
-75:25:56.8 |
HIP 67698 |
9.65 |
| 2026-03-29 00:00 |
13:54:15.39 |
-75:26:22.5 |
HIP 67698 |
8.42 |
| 2026-03-29 12:00 |
13:53:56.49 |
-75:26:47.6 |
HIP 67698 |
7.21 |
| 2026-03-30 00:00 |
13:53:37.49 |
-75:27:11.8 |
HIP 67698 |
6.00 |
| 2026-03-30 12:00 |
13:53:18.40 |
-75:27:35.3 |
HIP 67698 |
4.82 |
| 2026-03-31 00:00 |
13:52:59.23 |
-75:27:58.0 |
HIP 67698 |
3.68 |
| 2026-03-31 12:00 |
13:52:39.97 |
-75:28:19.9 |
HIP 67698 |
2.65 |
| 2026-04-01 00:00 |
13:52:20.62 |
-75:28:41.1 |
HIP 67698 |
1.90 |
| 2026-04-01 12:00 |
13:52:01.19 |
-75:29:01.5 |
HIP 67698 |
1.84 |
| 2026-04-02 00:00 |
13:51:41.69 |
-75:29:21.1 |
HIP 67698 |
2.51 |
| 2026-04-02 12:00 |
13:51:22.10 |
-75:29:39.9 |
HIP 67698 |
3.52 |
| 2026-04-03 00:00 |
13:51:02.44 |
-75:29:58.0 |
HIP 67698 |
4.65 |
| 2026-04-03 12:00 |
13:50:42.71 |
-75:30:15.2 |
HIP 67698 |
5.84 |
| 2026-04-04 00:00 |
13:50:22.91 |
-75:30:31.7 |
HIP 67698 |
7.05 |
| 2026-04-04 12:00 |
13:50:03.04 |
-75:30:47.4 |
HIP 67698 |
8.28 |
| 2026-04-05 00:00 |
13:49:43.10 |
-75:31:02.3 |
HIP 67698 |
9.51 |
| 2026-04-05 12:00 |
13:49:23.10 |
-75:31:16.4 |
HIP 67698 |
10.76 |
| 2026-04-06 00:00 |
13:49:03.04 |
-75:31:29.7 |
HIP 67698 |
12.01 |
| 2026-04-06 12:00 |
13:48:42.92 |
-75:31:42.2 |
HIP 67698 |
13.26 |
| 2026-04-07 00:00 |
13:48:22.75 |
-75:31:53.9 |
HIP 67698 |
14.51 |
| 2026-04-07 12:00 |
13:48:02.52 |
-75:32:04.8 |
HIP 67361 |
15.68 |
| 2026-04-08 00:00 |
13:47:42.24 |
-75:32:14.9 |
HIP 67361 |
15.66 |
| 2026-04-08 12:00 |
13:47:21.91 |
-75:32:24.2 |
HIP 67361 |
15.77 |
| 2026-04-09 00:00 |
13:47:01.53 |
-75:32:32.7 |
HIP 67361 |
15.98 |
| 2026-04-09 12:00 |
13:46:41.11 |
-75:32:40.4 |
HIP 67361 |
16.31 |
| 2026-04-10 00:00 |
13:46:20.65 |
-75:32:47.3 |
HIP 67361 |
16.74 |
| 2026-04-10 12:00 |
13:46:00.15 |
-75:32:53.4 |
HIP 67361 |
17.26 |
| 2026-04-11 00:00 |
13:45:39.61 |
-75:32:58.7 |
HIP 67361 |
17.88 |
| 2026-04-11 12:00 |
13:45:19.04 |
-75:33:03.2 |
HIP 67361 |
18.57 |
| 2026-04-12 00:00 |
13:44:58.44 |
-75:33:06.8 |
HIP 67361 |
19.33 |
| 2026-04-12 12:00 |
13:44:37.81 |
-75:33:09.7 |
HIP 67361 |
20.16 |
| 2026-04-13 00:00 |
13:44:17.16 |
-75:33:11.7 |
HIP 66607 |
20.50 |
| 2026-04-13 12:00 |
13:43:56.48 |
-75:33:13.0 |
HIP 66607 |
19.31 |
| 2026-04-14 00:00 |
13:43:35.78 |
-75:33:13.4 |
HIP 66607 |
18.14 |
| 2026-04-14 12:00 |
13:43:15.06 |
-75:33:13.0 |
HIP 66607 |
16.99 |
| 2026-04-15 00:00 |
13:42:54.33 |
-75:33:11.8 |
HIP 66607 |
15.87 |
| 2026-04-15 12:00 |
13:42:33.58 |
-75:33:09.8 |
HIP 66607 |
14.78 |
| 2026-04-16 00:00 |
13:42:12.83 |
-75:33:07.0 |
HIP 66607 |
13.73 |