メタデータ
| 項目 |
値 |
| Designation |
171P/Spahr |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2019-01-13T17:32:17.119680Z |
| Orbit solution date (soln_date, UTC) |
2026-03-07T15:25:06Z |
| Obs used |
681 |
| NEO |
- |
| M1 |
11.600 |
| K1 |
22.750 |
| PC |
0.030 |
オスキュレーティング軌道要素
| 項目 |
値 |
| Epoch (epoch_cal, TDB) |
2018-04-24.0000000 |
| e |
0.50194793 |
| q (au) |
1.772172 |
| a (au) |
3.558207 |
| i (deg) |
21.933094 |
| Ω (om, deg) |
101.699366 |
| ω (w, deg) |
347.157914 |
| M (ma, deg) |
321.125775 |
等級
散乱 + 全体線形
$$
M_a = (13.725 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
モデル定数
| 項目 |
値 |
| H0 |
13.725 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| 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
天体暦
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
11:13:01.60 |
+29:58:43.2 |
HIP 54729 |
17.29 |
| 2026-06-01 12:00 |
11:13:29.97 |
+29:52:45.9 |
HIP 54826 |
19.66 |
| 2026-06-02 00:00 |
11:13:58.48 |
+29:46:48.3 |
HIP 54826 |
15.45 |
| 2026-06-02 12:00 |
11:14:27.12 |
+29:40:50.6 |
HIP 54826 |
15.47 |
| 2026-06-03 00:00 |
11:14:55.90 |
+29:34:52.6 |
HIP 54826 |
19.75 |
| 2026-06-03 12:00 |
11:15:24.82 |
+29:28:54.4 |
HIP 55115 |
23.49 |
| 2026-06-04 00:00 |
11:15:53.87 |
+29:22:56.0 |
HIP 55115 |
15.58 |
| 2026-06-04 12:00 |
11:16:23.05 |
+29:16:57.5 |
HIP 55115 |
9.17 |
| 2026-06-05 00:00 |
11:16:52.36 |
+29:10:58.7 |
HIP 55115 |
8.80 |
| 2026-06-05 12:00 |
11:17:21.80 |
+29:04:59.8 |
HIP 55115 |
14.98 |
| 2026-06-06 00:00 |
11:17:51.37 |
+28:59:00.8 |
HIP 55115 |
22.94 |
| 2026-06-06 12:00 |
11:18:21.06 |
+28:53:01.5 |
HIP 55341 |
22.17 |
| 2026-06-07 00:00 |
11:18:50.87 |
+28:47:02.2 |
HIP 55341 |
15.24 |
| 2026-06-07 12:00 |
11:19:20.80 |
+28:41:02.6 |
HIP 55341 |
11.37 |
| 2026-06-08 00:00 |
11:19:50.86 |
+28:35:03.0 |
HIP 55341 |
13.56 |
| 2026-06-08 12:00 |
11:20:21.04 |
+28:29:03.2 |
HIP 55361 |
10.71 |
| 2026-06-09 00:00 |
11:20:51.33 |
+28:23:03.3 |
HIP 55361 |
10.12 |
| 2026-06-09 12:00 |
11:21:21.74 |
+28:17:03.3 |
HIP 55361 |
15.87 |
| 2026-06-10 00:00 |
11:21:52.27 |
+28:11:03.2 |
HIP 55370 |
21.29 |
| 2026-06-10 12:00 |
11:22:22.91 |
+28:05:02.9 |
HIP 55370 |
28.41 |
| 2026-06-11 00:00 |
11:22:53.66 |
+27:59:02.6 |
HIP 55370 |
36.43 |
| 2026-06-11 12:00 |
11:23:24.52 |
+27:53:02.2 |
HIP 55440 |
37.77 |
| 2026-06-12 00:00 |
11:23:55.50 |
+27:47:01.7 |
HIP 55680 |
34.41 |
| 2026-06-12 12:00 |
11:24:26.58 |
+27:41:01.2 |
HIP 55680 |
27.47 |
| 2026-06-13 00:00 |
11:24:57.77 |
+27:35:00.6 |
HIP 55680 |
22.20 |
| 2026-06-13 12:00 |
11:25:29.07 |
+27:29:00.0 |
HIP 55680 |
19.99 |
| 2026-06-14 00:00 |
11:26:00.47 |
+27:22:59.2 |
HIP 55786 |
13.81 |
| 2026-06-14 12:00 |
11:26:31.98 |
+27:16:58.5 |
HIP 55786 |
12.27 |
| 2026-06-15 00:00 |
11:27:03.59 |
+27:10:57.7 |
HIP 55786 |
16.79 |
| 2026-06-15 12:00 |
11:27:35.30 |
+27:04:56.9 |
HIP 55786 |
24.20 |
| 2026-06-16 00:00 |
11:28:07.10 |
+26:58:56.1 |
HIP 56142 |
31.35 |
| 2026-06-16 12:00 |
11:28:39.01 |
+26:52:55.2 |
HIP 56142 |
24.18 |
| 2026-06-17 00:00 |
11:29:11.02 |
+26:46:54.4 |
HIP 56142 |
18.92 |
| 2026-06-17 12:00 |
11:29:43.12 |
+26:40:53.7 |
HIP 56142 |
17.47 |
| 2026-06-18 00:00 |
11:30:15.31 |
+26:34:52.9 |
HIP 56142 |
20.66 |
| 2026-06-18 12:00 |
11:30:47.60 |
+26:28:52.2 |
HIP 56142 |
26.91 |
| 2026-06-19 00:00 |
11:31:19.98 |
+26:22:51.5 |
HIP 56373 |
29.49 |
| 2026-06-19 12:00 |
11:31:52.45 |
+26:16:50.9 |
HIP 56385 |
23.41 |
| 2026-06-20 00:00 |
11:32:25.01 |
+26:10:50.3 |
HIP 56385 |
14.83 |
| 2026-06-20 12:00 |
11:32:57.65 |
+26:04:49.8 |
HIP 56385 |
8.37 |
| 2026-06-21 00:00 |
11:33:30.38 |
+25:58:49.4 |
HIP 56385 |
9.98 |
| 2026-06-21 12:00 |
11:34:03.19 |
+25:52:49.0 |
HIP 56385 |
17.59 |
| 2026-06-22 00:00 |
11:34:36.09 |
+25:46:48.8 |
HIP 56554 |
20.34 |