メタデータ

項目	値
Designation	291P/NEAT
Type	P
Perihelion (tp_cal, UTC)	2013-12-15T08:00:33.684480Z
Orbit solution date (soln_date, UTC)	2024-05-30T01:12:35Z
Obs used	950
NEO	-
M1	8.300
K1	19.000
PC	0.030

オスキュレーティング軌道要素

項目	値
Epoch (epoch_cal, TDB)	2012-10-22.0000000
e	0.43049276
q (au)	2.591490
a (au)	4.550407
i (deg)	5.956694
Ω (om, deg)	241.044470
ω (w, deg)	176.028242
M (ma, deg)	317.421677

等級

散乱 + 全体線形

$$ M_a = (11.419 + 5.655\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目	値
H0	11.419
n	5.655
gf	0.807
gb	-0.768
k	0.973
δ90	1.000

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)
2026-07-29 00:00	12:49:05.22	-08:54:34.2	HIP 62551	18.68
2026-07-29 12:00	12:49:17.96	-08:55:29.6	HIP 62551	18.23
2026-07-30 00:00	12:49:30.80	-08:56:25.6	HIP 62551	18.37
2026-07-30 12:00	12:49:43.74	-08:57:22.4	HIP 62551	19.09
2026-07-31 00:00	12:49:56.79	-08:58:19.9	HIP 62551	20.34
2026-07-31 12:00	12:50:09.93	-08:59:18.1	HIP 62551	22.05
2026-08-01 00:00	12:50:23.17	-09:00:17.0	HIP 62551	24.13
2026-08-01 12:00	12:50:36.51	-09:01:16.5	HIP 62551	26.51
2026-08-02 00:00	12:50:49.95	-09:02:16.8	HIP 62551	29.12
2026-08-02 12:00	12:51:03.48	-09:03:17.8	HIP 62551	31.91
2026-08-03 00:00	12:51:17.11	-09:04:19.4	HIP 62844	30.85
2026-08-03 12:00	12:51:30.84	-09:05:21.7	HIP 62844	29.35
2026-08-04 00:00	12:51:44.66	-09:06:24.7	HIP 62844	28.21
2026-08-04 12:00	12:51:58.57	-09:07:28.4	HIP 62844	27.50
2026-08-05 00:00	12:52:12.58	-09:08:32.7	HIP 62844	27.25
2026-08-05 12:00	12:52:26.69	-09:09:37.7	HIP 62844	27.49
2026-08-06 00:00	12:52:40.88	-09:10:43.4	HIP 62844	28.21
2026-08-06 12:00	12:52:55.17	-09:11:49.7	HIP 62920	27.75
2026-08-07 00:00	12:53:09.55	-09:12:56.6	HIP 62920	25.42
2026-08-07 12:00	12:53:24.02	-09:14:04.2	HIP 62985	23.07
2026-08-08 00:00	12:53:38.58	-09:15:12.5	HIP 62985	20.09
2026-08-08 12:00	12:53:53.23	-09:16:21.3	HIP 62985	17.40
2026-08-09 00:00	12:54:07.97	-09:17:30.8	HIP 62985	15.18
2026-08-09 12:00	12:54:22.80	-09:18:41.0	HIP 62985	13.66
2026-08-10 00:00	12:54:37.72	-09:19:51.7	HIP 62985	13.12
2026-08-10 12:00	12:54:52.72	-09:21:03.1	HIP 62985	13.71
2026-08-11 00:00	12:55:07.81	-09:22:15.1	HIP 62985	15.30
2026-08-11 12:00	12:55:22.99	-09:23:27.7	HIP 62985	17.64
2026-08-12 00:00	12:55:38.25	-09:24:40.9	HIP 62985	20.49
2026-08-12 12:00	12:55:53.60	-09:25:54.7	HIP 62985	23.68
2026-08-13 00:00	12:56:09.03	-09:27:09.1	HIP 63240	26.96
2026-08-13 12:00	12:56:24.55	-09:28:24.1	HIP 63240	23.38
2026-08-14 00:00	12:56:40.15	-09:29:39.7	HIP 63240	19.96
2026-08-14 12:00	12:56:55.83	-09:30:55.8	HIP 63240	16.79
2026-08-15 00:00	12:57:11.59	-09:32:12.5	HIP 63240	14.09
2026-08-15 12:00	12:57:27.43	-09:33:29.8	HIP 63240	12.17
2026-08-16 00:00	12:57:43.35	-09:34:47.6	HIP 63240	11.46
2026-08-16 12:00	12:57:59.35	-09:36:06.0	HIP 63240	12.21
2026-08-17 00:00	12:58:15.43	-09:37:25.0	HIP 63240	14.20
2026-08-17 12:00	12:58:31.59	-09:38:44.5	HIP 63366	13.59
2026-08-18 00:00	12:58:47.82	-09:40:04.5	HIP 63366	10.60
2026-08-18 12:00	12:59:04.13	-09:41:25.1	HIP 63366	8.67
2026-08-19 00:00	12:59:20.51	-09:42:46.2	HIP 63366	8.60