メタデータ
| 項目 |
値 |
| Designation |
90P/Gehrels 1 |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2017-06-19T06:36:36.149760Z |
| Orbit solution date (soln_date, UTC) |
2022-05-24T23:57:55Z |
| Obs used |
577 |
| NEO |
- |
| M1 |
7.000 |
| K1 |
18.000 |
| PC |
0.030 |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2017-02-16.0000000 |
| e |
0.50979286 |
| q (au) |
2.974897 |
| a (au) |
6.068654 |
| i (deg) |
9.635376 |
| Ω (om, deg) |
13.251828 |
| ω (w, deg) |
29.270027 |
| M (ma, deg) |
351.872780 |
等級
散乱 + 全体線形
$$
M_a = (8.608 + 4.725\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
8.608 |
| n |
4.725 |
| gf |
1.000 |
| gb |
-0.828 |
| k |
1.000 |
| 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
残差 (区間線形)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| 開始日 (UTC) |
終了日 (UTC) |
a |
b |
| 2016-08-27 |
2017-01-18 |
+56.4715 |
-28.048 |
| 2017-07-30 |
2018-04-15 |
-5.8039 |
+3.002 |
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) |
| 2026-06-01 00:00 |
15:18:08.59 |
-25:52:55.8 |
HIP 74912 |
20.60 |
| 2026-06-01 12:00 |
15:17:57.16 |
-25:52:13.3 |
HIP 74912 |
20.76 |
| 2026-06-02 00:00 |
15:17:45.79 |
-25:51:30.8 |
HIP 74912 |
21.25 |
| 2026-06-02 12:00 |
15:17:34.46 |
-25:50:48.1 |
HIP 74912 |
22.05 |
| 2026-06-03 00:00 |
15:17:23.19 |
-25:50:05.3 |
HIP 74912 |
23.12 |
| 2026-06-03 12:00 |
15:17:11.97 |
-25:49:22.4 |
HIP 74912 |
24.41 |
| 2026-06-04 00:00 |
15:17:00.80 |
-25:48:39.4 |
HIP 74912 |
25.90 |
| 2026-06-04 12:00 |
15:16:49.70 |
-25:47:56.4 |
HIP 74912 |
27.54 |
| 2026-06-05 00:00 |
15:16:38.65 |
-25:47:13.2 |
HIP 74912 |
29.31 |
| 2026-06-05 12:00 |
15:16:27.65 |
-25:46:30.0 |
HIP 74655 |
28.10 |
| 2026-06-06 00:00 |
15:16:16.72 |
-25:45:46.7 |
HIP 74655 |
26.16 |
| 2026-06-06 12:00 |
15:16:05.85 |
-25:45:03.3 |
HIP 74655 |
24.34 |
| 2026-06-07 00:00 |
15:15:55.05 |
-25:44:19.9 |
HIP 74655 |
22.66 |
| 2026-06-07 12:00 |
15:15:44.30 |
-25:43:36.5 |
HIP 74655 |
21.16 |
| 2026-06-08 00:00 |
15:15:33.62 |
-25:42:53.0 |
HIP 74573 |
18.82 |
| 2026-06-08 12:00 |
15:15:23.01 |
-25:42:09.4 |
HIP 74573 |
16.33 |
| 2026-06-09 00:00 |
15:15:12.47 |
-25:41:25.9 |
HIP 74573 |
13.87 |
| 2026-06-09 12:00 |
15:15:01.99 |
-25:40:42.3 |
HIP 74573 |
11.42 |
| 2026-06-10 00:00 |
15:14:51.58 |
-25:39:58.7 |
HIP 74573 |
9.00 |
| 2026-06-10 12:00 |
15:14:41.25 |
-25:39:15.0 |
HIP 74573 |
6.62 |
| 2026-06-11 00:00 |
15:14:30.98 |
-25:38:31.4 |
HIP 74573 |
4.34 |
| 2026-06-11 12:00 |
15:14:20.79 |
-25:37:47.8 |
HIP 74573 |
2.35 |
| 2026-06-12 00:00 |
15:14:10.67 |
-25:37:04.2 |
HIP 74573 |
1.97 |
| 2026-06-12 12:00 |
15:14:00.63 |
-25:36:20.6 |
HIP 74573 |
3.68 |
| 2026-06-13 00:00 |
15:13:50.67 |
-25:35:37.0 |
HIP 74573 |
5.87 |
| 2026-06-13 12:00 |
15:13:40.78 |
-25:34:53.5 |
HIP 74573 |
8.13 |
| 2026-06-14 00:00 |
15:13:30.98 |
-25:34:10.0 |
HIP 74573 |
10.42 |
| 2026-06-14 12:00 |
15:13:21.25 |
-25:33:26.6 |
HIP 74573 |
12.70 |
| 2026-06-15 00:00 |
15:13:11.61 |
-25:32:43.2 |
HIP 74500 |
14.70 |
| 2026-06-15 12:00 |
15:13:02.04 |
-25:31:59.8 |
HIP 74500 |
14.75 |
| 2026-06-16 00:00 |
15:12:52.57 |
-25:31:16.5 |
HIP 74500 |
15.14 |
| 2026-06-16 12:00 |
15:12:43.17 |
-25:30:33.3 |
HIP 74500 |
15.84 |
| 2026-06-17 00:00 |
15:12:33.86 |
-25:29:50.2 |
HIP 74500 |
16.79 |
| 2026-06-17 12:00 |
15:12:24.64 |
-25:29:07.2 |
HIP 74500 |
17.96 |
| 2026-06-18 00:00 |
15:12:15.51 |
-25:28:24.2 |
HIP 74500 |
19.29 |
| 2026-06-18 12:00 |
15:12:06.46 |
-25:27:41.4 |
HIP 74500 |
20.75 |
| 2026-06-19 00:00 |
15:11:57.51 |
-25:26:58.6 |
HIP 74500 |
22.30 |
| 2026-06-19 12:00 |
15:11:48.65 |
-25:26:16.0 |
HIP 74500 |
23.93 |
| 2026-06-20 00:00 |
15:11:39.87 |
-25:25:33.5 |
HIP 74500 |
25.61 |
| 2026-06-20 12:00 |
15:11:31.19 |
-25:24:51.1 |
HIP 74500 |
27.33 |
| 2026-06-21 00:00 |
15:11:22.60 |
-25:24:08.9 |
HIP 74500 |
29.08 |
| 2026-06-21 12:00 |
15:11:14.11 |
-25:23:26.7 |
HIP 74500 |
30.85 |
| 2026-06-22 00:00 |
15:11:05.71 |
-25:22:44.8 |
HIP 74175 |
29.78 |