Metadata

Parameter	Value
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

Osculating Elements

Parameter	Value
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

Magnitude

Scatter + Global Linear

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

Model Parameters

Parameter	Value
H0	9.967
n	5.380
gf	0.800
gb	-0.500
k	1.000
δ90	1.000

Parameter	Symbol	Range	Description
Absolute magnitude at 1 AU from Sun and Earth	H0	-5 to 20	Intrinsic brightness of the comet
Photometric slope parameter	n	2 to 6	Rate of brightness change with heliocentric distance
Forward scattering asymmetry factor	gf	0.8 to 1	Degree of forward scattering
Backward scattering asymmetry factor	gb	-1 to -0.5	Degree of backward scattering
Partitioning coefficient	k	0.8 to 1	Ratio between forward/backward scattering contributions
Dust-to-gas brightness ratio	δ90	1 to 10	Relative contribution of dust scattering to gas emission

Reference: EPSC-DPS2025-160

Residuals (Piecewise)

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

Start (UTC)	End (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(heliocentric distance / AU), Δ = geocentric distance (AU)

Ephemeris

Date/Time (UTC)	RA (J2000)	Dec (J2000)	Nearest HIP	Dist from HIP (arcmin)
2026-03-26 00:00	00:42:23.20	+36:43:47.0	HIP 3469	23.74
2026-03-26 12:00	00:42:26.32	+36:43:57.4	HIP 3469	23.10
2026-03-27 00:00	00:42:29.44	+36:44:08.0	HIP 3469	22.46
2026-03-27 12:00	00:42:32.56	+36:44:18.8	HIP 3469	21.82
2026-03-28 00:00	00:42:35.69	+36:44:29.8	HIP 3469	21.18
2026-03-28 12:00	00:42:38.81	+36:44:41.0	HIP 3469	20.54
2026-03-29 00:00	00:42:41.94	+36:44:52.4	HIP 3469	19.90
2026-03-29 12:00	00:42:45.07	+36:45:03.9	HIP 3469	19.27
2026-03-30 00:00	00:42:48.20	+36:45:15.6	HIP 3469	18.63
2026-03-30 12:00	00:42:51.33	+36:45:27.5	HIP 3469	18.00
2026-03-31 00:00	00:42:54.46	+36:45:39.6	HIP 3469	17.36
2026-03-31 12:00	00:42:57.59	+36:45:51.9	HIP 3469	16.73
2026-04-01 00:00	00:43:00.72	+36:46:04.3	HIP 3469	16.10
2026-04-01 12:00	00:43:03.86	+36:46:16.9	HIP 3469	15.47
2026-04-02 00:00	00:43:06.99	+36:46:29.7	HIP 3469	14.85
2026-04-02 12:00	00:43:10.12	+36:46:42.7	HIP 3469	14.23
2026-04-03 00:00	00:43:13.25	+36:46:55.9	HIP 3469	13.61
2026-04-03 12:00	00:43:16.38	+36:47:09.2	HIP 3469	13.00
2026-04-04 00:00	00:43:19.51	+36:47:22.7	HIP 3469	12.40
2026-04-04 12:00	00:43:22.64	+36:47:36.4	HIP 3469	11.80
2026-04-05 00:00	00:43:25.77	+36:47:50.2	HIP 3469	11.21
2026-04-05 12:00	00:43:28.89	+36:48:04.2	HIP 3469	10.64
2026-04-06 00:00	00:43:32.02	+36:48:18.4	HIP 3469	10.07
2026-04-06 12:00	00:43:35.14	+36:48:32.8	HIP 3469	9.52
2026-04-07 00:00	00:43:38.26	+36:48:47.3	HIP 3469	8.98
2026-04-07 12:00	00:43:41.37	+36:49:02.0	HIP 3469	8.47
2026-04-08 00:00	00:43:44.49	+36:49:16.8	HIP 3469	7.98
2026-04-08 12:00	00:43:47.60	+36:49:31.9	HIP 3469	7.52
2026-04-09 00:00	00:43:50.71	+36:49:47.0	HIP 3469	7.10
2026-04-09 12:00	00:43:53.82	+36:50:02.4	HIP 3469	6.72
2026-04-10 00:00	00:43:56.92	+36:50:17.9	HIP 3469	6.39
2026-04-10 12:00	00:44:00.02	+36:50:33.6	HIP 3469	6.12
2026-04-11 00:00	00:44:03.12	+36:50:49.4	HIP 3469	5.92
2026-04-11 12:00	00:44:06.21	+36:51:05.4	HIP 3469	5.79
2026-04-12 00:00	00:44:09.30	+36:51:21.5	HIP 3469	5.74
2026-04-12 12:00	00:44:12.38	+36:51:37.8	HIP 3469	5.77
2026-04-13 00:00	00:44:15.46	+36:51:54.3	HIP 3469	5.88
2026-04-13 12:00	00:44:18.53	+36:52:10.9	HIP 3469	6.07
2026-04-14 00:00	00:44:21.60	+36:52:27.6	HIP 3469	6.33
2026-04-14 12:00	00:44:24.67	+36:52:44.5	HIP 3469	6.65
2026-04-15 00:00	00:44:27.72	+36:53:01.6	HIP 3469	7.02
2026-04-15 12:00	00:44:30.78	+36:53:18.8	HIP 3469	7.44
2026-04-16 00:00	00:44:33.82	+36:53:36.2	HIP 3469	7.89