メタデータ

項目	値
Designation	C/2004 F4 (Bradfield)
Type	C
Perihelion (tp_cal, UTC)	2004-04-17T02:09:33.935040Z
Orbit solution date (soln_date, UTC)	2021-04-15T23:30:39Z
Obs used	301
NEO	-
M1	11.300
K1	17.500
PC	0.030

オスキュレーティング軌道要素

項目	値
Epoch (epoch_cal, TDB)	2004-06-01.0000000
e	0.99929199
q (au)	0.168266
a (au)	237.660852
i (deg)	63.164572
Ω (om, deg)	222.778071
ω (w, deg)	332.785994
M (ma, deg)	0.012081

等級

散乱 + 全体線形

$$ M_a = (9.967 + 5.380\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

モデル定数

項目	値
H0	9.967
n	5.380
gf	0.800
gb	-0.500
k	1.000
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

残差 (区間線形)

$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$

開始日 (UTC)	終了日 (UTC)	a	b
2004-04-23	2004-05-15	-5.2994	-1.665
2004-05-15	2004-05-23	+0.5100	-0.724
2004-05-23	2004-07-10	+6.7542	-0.675
2004-07-10	2004-09-01	-1.5504	+1.328

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)
2026-05-12 00:00	00:46:59.34	+37:11:26.2	HIP 3687	6.06
2026-05-12 12:00	00:47:01.80	+37:11:49.4	HIP 3687	5.47
2026-05-13 00:00	00:47:04.25	+37:12:12.6	HIP 3687	4.90
2026-05-13 12:00	00:47:06.68	+37:12:35.8	HIP 3687	4.33
2026-05-14 00:00	00:47:09.10	+37:12:59.2	HIP 3687	3.79
2026-05-14 12:00	00:47:11.50	+37:13:22.6	HIP 3687	3.27
2026-05-15 00:00	00:47:13.88	+37:13:46.1	HIP 3687	2.79
2026-05-15 12:00	00:47:16.25	+37:14:09.6	HIP 3687	2.37
2026-05-16 00:00	00:47:18.60	+37:14:33.2	HIP 3687	2.05
2026-05-16 12:00	00:47:20.94	+37:14:56.8	HIP 3687	1.87
2026-05-17 00:00	00:47:23.25	+37:15:20.5	HIP 3687	1.88
2026-05-17 12:00	00:47:25.55	+37:15:44.3	HIP 3687	2.08
2026-05-18 00:00	00:47:27.83	+37:16:08.1	HIP 3687	2.41
2026-05-18 12:00	00:47:30.10	+37:16:32.0	HIP 3687	2.83
2026-05-19 00:00	00:47:32.34	+37:16:55.9	HIP 3687	3.30
2026-05-19 12:00	00:47:34.57	+37:17:19.9	HIP 3687	3.80
2026-05-20 00:00	00:47:36.78	+37:17:43.9	HIP 3687	4.33
2026-05-20 12:00	00:47:38.97	+37:18:08.0	HIP 3687	4.87
2026-05-21 00:00	00:47:41.15	+37:18:32.1	HIP 3687	5.41
2026-05-21 12:00	00:47:43.30	+37:18:56.2	HIP 3687	5.96
2026-05-22 00:00	00:47:45.44	+37:19:20.4	HIP 3687	6.52
2026-05-22 12:00	00:47:47.55	+37:19:44.6	HIP 3687	7.07
2026-05-23 00:00	00:47:49.65	+37:20:08.9	HIP 3687	7.63
2026-05-23 12:00	00:47:51.73	+37:20:33.2	HIP 3687	8.19
2026-05-24 00:00	00:47:53.79	+37:20:57.5	HIP 3687	8.74
2026-05-24 12:00	00:47:55.83	+37:21:21.9	HIP 3687	9.30
2026-05-25 00:00	00:47:57.85	+37:21:46.3	HIP 3687	9.86
2026-05-25 12:00	00:47:59.85	+37:22:10.7	HIP 3687	10.41
2026-05-26 00:00	00:48:01.84	+37:22:35.1	HIP 3687	10.96
2026-05-26 12:00	00:48:03.80	+37:22:59.6	HIP 3687	11.51
2026-05-27 00:00	00:48:05.74	+37:23:24.1	HIP 3687	12.06
2026-05-27 12:00	00:48:07.66	+37:23:48.6	HIP 3687	12.61
2026-05-28 00:00	00:48:09.56	+37:24:13.2	HIP 3687	13.15
2026-05-28 12:00	00:48:11.44	+37:24:37.7	HIP 3687	13.70
2026-05-29 00:00	00:48:13.30	+37:25:02.3	HIP 3687	14.24
2026-05-29 12:00	00:48:15.15	+37:25:26.9	HIP 3714	14.14
2026-05-30 00:00	00:48:16.97	+37:25:51.5	HIP 3714	13.96
2026-05-30 12:00	00:48:18.76	+37:26:16.1	HIP 3714	13.80
2026-05-31 00:00	00:48:20.54	+37:26:40.8	HIP 3714	13.66
2026-05-31 12:00	00:48:22.30	+37:27:05.4	HIP 3714	13.53
2026-06-01 00:00	00:48:24.04	+37:27:30.1	HIP 3714	13.42
2026-06-01 12:00	00:48:25.75	+37:27:54.7	HIP 3714	13.33
2026-06-02 00:00	00:48:27.44	+37:28:19.4	HIP 3714	13.26