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)
2026-07-29 00:00	00:48:59.83	+38:08:57.8	HIP 3859	7.44
2026-07-29 12:00	00:48:58.64	+38:09:12.4	HIP 3859	7.54
2026-07-30 00:00	00:48:57.41	+38:09:26.9	HIP 3859	7.67
2026-07-30 12:00	00:48:56.17	+38:09:41.2	HIP 3859	7.82
2026-07-31 00:00	00:48:54.90	+38:09:55.4	HIP 3859	7.98
2026-07-31 12:00	00:48:53.60	+38:10:09.3	HIP 3859	8.16
2026-08-01 00:00	00:48:52.28	+38:10:23.1	HIP 3859	8.35
2026-08-01 12:00	00:48:50.94	+38:10:36.8	HIP 3859	8.56
2026-08-02 00:00	00:48:49.57	+38:10:50.2	HIP 3859	8.79
2026-08-02 12:00	00:48:48.17	+38:11:03.5	HIP 3859	9.02
2026-08-03 00:00	00:48:46.75	+38:11:16.6	HIP 3859	9.27
2026-08-03 12:00	00:48:45.31	+38:11:29.5	HIP 3859	9.53
2026-08-04 00:00	00:48:43.84	+38:11:42.2	HIP 3859	9.80
2026-08-04 12:00	00:48:42.35	+38:11:54.7	HIP 3859	10.09
2026-08-05 00:00	00:48:40.84	+38:12:07.1	HIP 3859	10.38
2026-08-05 12:00	00:48:39.30	+38:12:19.3	HIP 3859	10.68
2026-08-06 00:00	00:48:37.74	+38:12:31.2	HIP 3859	10.99
2026-08-06 12:00	00:48:36.15	+38:12:43.0	HIP 3859	11.30
2026-08-07 00:00	00:48:34.54	+38:12:54.7	HIP 3859	11.63
2026-08-07 12:00	00:48:32.91	+38:13:06.1	HIP 3859	11.96
2026-08-08 00:00	00:48:31.25	+38:13:17.3	HIP 3859	12.30
2026-08-08 12:00	00:48:29.57	+38:13:28.3	HIP 3859	12.64
2026-08-09 00:00	00:48:27.86	+38:13:39.2	HIP 3859	12.99
2026-08-09 12:00	00:48:26.14	+38:13:49.8	HIP 3859	13.35
2026-08-10 00:00	00:48:24.39	+38:14:00.3	HIP 3859	13.71
2026-08-10 12:00	00:48:22.61	+38:14:10.5	HIP 3859	14.08
2026-08-11 00:00	00:48:20.82	+38:14:20.6	HIP 3859	14.45
2026-08-11 12:00	00:48:19.00	+38:14:30.4	HIP 3859	14.83
2026-08-12 00:00	00:48:17.16	+38:14:40.1	HIP 3859	15.21
2026-08-12 12:00	00:48:15.29	+38:14:49.5	HIP 3859	15.60
2026-08-13 00:00	00:48:13.40	+38:14:58.8	HIP 3859	15.99
2026-08-13 12:00	00:48:11.50	+38:15:07.8	HIP 3859	16.38
2026-08-14 00:00	00:48:09.57	+38:15:16.7	HIP 3859	16.78
2026-08-14 12:00	00:48:07.61	+38:15:25.3	HIP 3859	17.18
2026-08-15 00:00	00:48:05.64	+38:15:33.7	HIP 3859	17.59
2026-08-15 12:00	00:48:03.64	+38:15:42.0	HIP 3859	18.00
2026-08-16 00:00	00:48:01.62	+38:15:50.0	HIP 3859	18.41
2026-08-16 12:00	00:47:59.58	+38:15:57.8	HIP 3859	18.83
2026-08-17 00:00	00:47:57.52	+38:16:05.4	HIP 3859	19.25
2026-08-17 12:00	00:47:55.44	+38:16:12.8	HIP 3859	19.68
2026-08-18 00:00	00:47:53.34	+38:16:20.0	HIP 3859	20.11
2026-08-18 12:00	00:47:51.22	+38:16:26.9	HIP 3859	20.54
2026-08-19 00:00	00:47:49.07	+38:16:33.7	HIP 3859	20.97