メタデータ

項目	値
Designation	374P/Larson
Type	P
Perihelion (tp_cal, UTC)	2007-12-09T18:00:31.363200Z
Orbit solution date (soln_date, UTC)	2021-04-15T23:28:38Z
Obs used	286
NEO	-
M1	7.400
K1	23.750
PC	0.030

オスキュレーティング軌道要素

項目	値
Epoch (epoch_cal, TDB)	2011-05-22.0000000
e	0.46250522
q (au)	2.670592
a (au)	4.968591
i (deg)	10.790852
Ω (om, deg)	8.161322
ω (w, deg)	51.420244
M (ma, deg)	112.063968

等級

散乱 + 全体線形

$$ M_a = (12.335 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目	値
H0	12.335
n	6.000
gf	1.000
gb	-0.533
k	0.800
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)
2026-09-20 00:00	17:18:58.14	-33:46:24.7	HIP 84685	20.14
2026-09-20 12:00	17:19:07.05	-33:45:47.1	HIP 84685	19.88
2026-09-21 00:00	17:19:16.12	-33:45:09.6	HIP 84685	19.83
2026-09-21 12:00	17:19:25.35	-33:44:32.5	HIP 84685	20.00
2026-09-22 00:00	17:19:34.75	-33:43:55.5	HIP 84685	20.39
2026-09-22 12:00	17:19:44.30	-33:43:18.8	HIP 84685	21.00
2026-09-23 00:00	17:19:54.02	-33:42:42.4	HIP 84685	21.82
2026-09-23 12:00	17:20:03.89	-33:42:06.2	HIP 84685	22.83
2026-09-24 00:00	17:20:13.93	-33:41:30.3	HIP 84685	24.02
2026-09-24 12:00	17:20:24.12	-33:40:54.6	HIP 84966	25.32
2026-09-25 00:00	17:20:34.46	-33:40:19.2	HIP 84966	23.30
2026-09-25 12:00	17:20:44.96	-33:39:44.0	HIP 84966	21.30
2026-09-26 00:00	17:20:55.62	-33:39:09.1	HIP 84966	19.33
2026-09-26 12:00	17:21:06.43	-33:38:34.4	HIP 84966	17.43
2026-09-27 00:00	17:21:17.40	-33:38:00.0	HIP 84966	15.64
2026-09-27 12:00	17:21:28.51	-33:37:25.8	HIP 84966	13.99
2026-09-28 00:00	17:21:39.78	-33:36:51.8	HIP 84966	12.59
2026-09-28 12:00	17:21:51.21	-33:36:18.1	HIP 84966	11.52
2026-09-29 00:00	17:22:02.78	-33:35:44.6	HIP 84966	10.91
2026-09-29 12:00	17:22:14.50	-33:35:11.4	HIP 84966	10.86
2026-09-30 00:00	17:22:26.37	-33:34:38.5	HIP 84966	11.40
2026-09-30 12:00	17:22:38.40	-33:34:05.7	HIP 84966	12.47
2026-10-01 00:00	17:22:50.57	-33:33:33.2	HIP 84966	13.95
2026-10-01 12:00	17:23:02.88	-33:33:01.0	HIP 84966	15.76
2026-10-02 00:00	17:23:15.35	-33:32:29.0	HIP 85082	16.71
2026-10-02 12:00	17:23:27.96	-33:31:57.2	HIP 85082	17.36
2026-10-03 00:00	17:23:40.72	-33:31:25.7	HIP 85082	18.39
2026-10-03 12:00	17:23:53.62	-33:30:54.4	HIP 85082	19.74
2026-10-04 00:00	17:24:06.67	-33:30:23.3	HIP 85082	21.37
2026-10-04 12:00	17:24:19.86	-33:29:52.5	HIP 85082	23.23
2026-10-05 00:00	17:24:33.19	-33:29:21.9	HIP 85082	25.28
2026-10-05 12:00	17:24:46.67	-33:28:51.5	HIP 85082	27.48
2026-10-06 00:00	17:25:00.29	-33:28:21.4	HIP 85375	29.49
2026-10-06 12:00	17:25:14.05	-33:27:51.5	HIP 85375	27.87
2026-10-07 00:00	17:25:27.95	-33:27:21.9	HIP 85375	26.46
2026-10-07 12:00	17:25:41.99	-33:26:52.4	HIP 85375	25.29
2026-10-08 00:00	17:25:56.17	-33:26:23.2	HIP 85375	24.41
2026-10-08 12:00	17:26:10.49	-33:25:54.2	HIP 85375	23.86
2026-10-09 00:00	17:26:24.95	-33:25:25.5	HIP 85375	23.68
2026-10-09 12:00	17:26:39.54	-33:24:56.9	HIP 85375	23.89
2026-10-10 00:00	17:26:54.27	-33:24:28.6	HIP 85375	24.49
2026-10-10 12:00	17:27:09.13	-33:24:00.6	HIP 85375	25.45
2026-10-11 00:00	17:27:24.13	-33:23:32.7	HIP 85375	26.75