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) |
| 2026-03-26 00:00 |
15:41:32.98 |
-26:37:38.2 |
HIP 76872 |
28.91 |
| 2026-03-26 12:00 |
15:41:27.30 |
-26:37:47.9 |
HIP 76872 |
29.25 |
| 2026-03-27 00:00 |
15:41:21.51 |
-26:37:57.0 |
HIP 76872 |
29.65 |
| 2026-03-27 12:00 |
15:41:15.61 |
-26:38:05.7 |
HIP 76872 |
30.09 |
| 2026-03-28 00:00 |
15:41:09.59 |
-26:38:14.0 |
HIP 76872 |
30.59 |
| 2026-03-28 12:00 |
15:41:03.45 |
-26:38:21.7 |
HIP 76872 |
31.13 |
| 2026-03-29 00:00 |
15:40:57.21 |
-26:38:29.0 |
HIP 76872 |
31.73 |
| 2026-03-29 12:00 |
15:40:50.85 |
-26:38:35.9 |
HIP 76611 |
30.86 |
| 2026-03-30 00:00 |
15:40:44.38 |
-26:38:42.3 |
HIP 76611 |
29.49 |
| 2026-03-30 12:00 |
15:40:37.80 |
-26:38:48.2 |
HIP 76611 |
28.10 |
| 2026-03-31 00:00 |
15:40:31.11 |
-26:38:53.6 |
HIP 76611 |
26.71 |
| 2026-03-31 12:00 |
15:40:24.31 |
-26:38:58.6 |
HIP 76611 |
25.32 |
| 2026-04-01 00:00 |
15:40:17.40 |
-26:39:03.1 |
HIP 76611 |
23.91 |
| 2026-04-01 12:00 |
15:40:10.39 |
-26:39:07.1 |
HIP 76611 |
22.52 |
| 2026-04-02 00:00 |
15:40:03.26 |
-26:39:10.6 |
HIP 76611 |
21.13 |
| 2026-04-02 12:00 |
15:39:56.03 |
-26:39:13.7 |
HIP 76611 |
19.75 |
| 2026-04-03 00:00 |
15:39:48.69 |
-26:39:16.3 |
HIP 76611 |
18.40 |
| 2026-04-03 12:00 |
15:39:41.25 |
-26:39:18.4 |
HIP 76611 |
17.09 |
| 2026-04-04 00:00 |
15:39:33.70 |
-26:39:20.1 |
HIP 76611 |
15.83 |
| 2026-04-04 12:00 |
15:39:26.04 |
-26:39:21.2 |
HIP 76611 |
14.65 |
| 2026-04-05 00:00 |
15:39:18.29 |
-26:39:21.9 |
HIP 76611 |
13.57 |
| 2026-04-05 12:00 |
15:39:10.43 |
-26:39:22.1 |
HIP 76611 |
12.64 |
| 2026-04-06 00:00 |
15:39:02.47 |
-26:39:21.9 |
HIP 76611 |
11.89 |
| 2026-04-06 12:00 |
15:38:54.41 |
-26:39:21.1 |
HIP 76611 |
11.38 |
| 2026-04-07 00:00 |
15:38:46.24 |
-26:39:19.9 |
HIP 76611 |
11.14 |
| 2026-04-07 12:00 |
15:38:37.98 |
-26:39:18.1 |
HIP 76611 |
11.22 |
| 2026-04-08 00:00 |
15:38:29.62 |
-26:39:15.9 |
HIP 76611 |
11.60 |
| 2026-04-08 12:00 |
15:38:21.16 |
-26:39:13.2 |
HIP 76611 |
12.27 |
| 2026-04-09 00:00 |
15:38:12.61 |
-26:39:10.0 |
HIP 76611 |
13.20 |
| 2026-04-09 12:00 |
15:38:03.95 |
-26:39:06.4 |
HIP 76611 |
14.34 |
| 2026-04-10 00:00 |
15:37:55.21 |
-26:39:02.2 |
HIP 76473 |
14.38 |
| 2026-04-10 12:00 |
15:37:46.36 |
-26:38:57.6 |
HIP 76473 |
12.91 |
| 2026-04-11 00:00 |
15:37:37.43 |
-26:38:52.4 |
HIP 76473 |
11.56 |
| 2026-04-11 12:00 |
15:37:28.40 |
-26:38:46.8 |
HIP 76473 |
10.42 |
| 2026-04-12 00:00 |
15:37:19.28 |
-26:38:40.7 |
HIP 76473 |
9.55 |
| 2026-04-12 12:00 |
15:37:10.07 |
-26:38:34.1 |
HIP 76473 |
9.05 |
| 2026-04-13 00:00 |
15:37:00.77 |
-26:38:27.1 |
HIP 76473 |
9.01 |
| 2026-04-13 12:00 |
15:36:51.39 |
-26:38:19.5 |
HIP 76473 |
9.44 |
| 2026-04-14 00:00 |
15:36:41.91 |
-26:38:11.4 |
HIP 76473 |
10.30 |
| 2026-04-14 12:00 |
15:36:32.35 |
-26:38:02.9 |
HIP 76473 |
11.49 |
| 2026-04-15 00:00 |
15:36:22.70 |
-26:37:53.9 |
HIP 76473 |
12.94 |
| 2026-04-15 12:00 |
15:36:12.97 |
-26:37:44.4 |
HIP 76473 |
14.58 |
| 2026-04-16 00:00 |
15:36:03.16 |
-26:37:34.4 |
HIP 76473 |
16.36 |