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)
2026-09-20 00:00	00:44:57.31	+38:16:06.4	HIP 3228	45.52
2026-09-20 12:00	00:44:54.23	+38:15:58.6	HIP 3228	44.92
2026-09-21 00:00	00:44:51.15	+38:15:50.7	HIP 3228	44.32
2026-09-21 12:00	00:44:48.05	+38:15:42.5	HIP 3228	43.72
2026-09-22 00:00	00:44:44.95	+38:15:34.0	HIP 3228	43.11
2026-09-22 12:00	00:44:41.85	+38:15:25.4	HIP 3228	42.51
2026-09-23 00:00	00:44:38.73	+38:15:16.5	HIP 3228	41.90
2026-09-23 12:00	00:44:35.62	+38:15:07.4	HIP 3228	41.30
2026-09-24 00:00	00:44:32.49	+38:14:58.1	HIP 3228	40.69
2026-09-24 12:00	00:44:29.36	+38:14:48.6	HIP 3228	40.09
2026-09-25 00:00	00:44:26.23	+38:14:38.9	HIP 3228	39.48
2026-09-25 12:00	00:44:23.09	+38:14:28.9	HIP 3228	38.88
2026-09-26 00:00	00:44:19.94	+38:14:18.7	HIP 3228	38.27
2026-09-26 12:00	00:44:16.80	+38:14:08.4	HIP 3228	37.67
2026-09-27 00:00	00:44:13.64	+38:13:57.7	HIP 3228	37.06
2026-09-27 12:00	00:44:10.49	+38:13:46.9	HIP 3228	36.46
2026-09-28 00:00	00:44:07.33	+38:13:35.9	HIP 3228	35.86
2026-09-28 12:00	00:44:04.16	+38:13:24.7	HIP 3228	35.26
2026-09-29 00:00	00:44:00.99	+38:13:13.2	HIP 3228	34.66
2026-09-29 12:00	00:43:57.82	+38:13:01.5	HIP 3228	34.06
2026-09-30 00:00	00:43:54.65	+38:12:49.6	HIP 3228	33.46
2026-09-30 12:00	00:43:51.48	+38:12:37.5	HIP 3228	32.87
2026-10-01 00:00	00:43:48.30	+38:12:25.2	HIP 3228	32.28
2026-10-01 12:00	00:43:45.12	+38:12:12.7	HIP 3228	31.69
2026-10-02 00:00	00:43:41.94	+38:12:00.0	HIP 3228	31.10
2026-10-02 12:00	00:43:38.75	+38:11:47.1	HIP 3228	30.52
2026-10-03 00:00	00:43:35.57	+38:11:33.9	HIP 3228	29.94
2026-10-03 12:00	00:43:32.38	+38:11:20.6	HIP 3228	29.37
2026-10-04 00:00	00:43:29.20	+38:11:07.0	HIP 3228	28.80
2026-10-04 12:00	00:43:26.01	+38:10:53.3	HIP 3228	28.23
2026-10-05 00:00	00:43:22.82	+38:10:39.3	HIP 3228	27.67
2026-10-05 12:00	00:43:19.64	+38:10:25.1	HIP 3228	27.11
2026-10-06 00:00	00:43:16.45	+38:10:10.8	HIP 3228	26.57
2026-10-06 12:00	00:43:13.26	+38:09:56.2	HIP 3228	26.02
2026-10-07 00:00	00:43:10.08	+38:09:41.4	HIP 3228	25.49
2026-10-07 12:00	00:43:06.89	+38:09:26.5	HIP 3228	24.96
2026-10-08 00:00	00:43:03.71	+38:09:11.3	HIP 3228	24.44
2026-10-08 12:00	00:43:00.53	+38:08:55.9	HIP 3228	23.93
2026-10-09 00:00	00:42:57.35	+38:08:40.4	HIP 3228	23.43
2026-10-09 12:00	00:42:54.17	+38:08:24.6	HIP 3228	22.94
2026-10-10 00:00	00:42:50.99	+38:08:08.7	HIP 3228	22.46
2026-10-10 12:00	00:42:47.82	+38:07:52.5	HIP 3228	21.99
2026-10-11 00:00	00:42:44.65	+38:07:36.2	HIP 3228	21.54