Metadata

Parameter	Value
Designation	C/1942 X1 (Whipple-Fedtke-Tevzadze)
Type	C
Perihelion (tp_cal, UTC)	1943-02-06T17:18:23.040000Z
Orbit solution date (soln_date, UTC)	-
Obs used	166
NEO	-
M1	-
K1	-
PC	-

Osculating Elements

Parameter	Value
Epoch (epoch_cal, TDB)	1943-02-05.0000000
e	0.99219600
q (au)	1.353647
a (au)	173.455536
i (deg)	19.712700
Ω (om, deg)	100.799000
ω (w, deg)	39.843200
M (ma, deg)	-0.000743

Magnitude

Scatter + Global Linear

$$ M_a = (3.857 + 3.863\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

Model Parameters

Parameter	Value
H0	3.857
n	3.863
gf	1.000
gb	-0.500
k	1.000
δ90	10.000

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
1942-12-15	1943-02-06	+38.1961	-4.915
1943-02-06	1943-04-13	+2.8278	-0.764
1943-04-13	1943-06-05	-2.7997	+0.823

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	20:50:37.00	-27:23:53.0	HIP 102848	7.07
2026-09-20 12:00	20:50:36.15	-27:23:54.0	HIP 102848	6.90
2026-09-21 00:00	20:50:35.31	-27:23:55.0	HIP 102848	6.72
2026-09-21 12:00	20:50:34.47	-27:23:55.8	HIP 102848	6.55
2026-09-22 00:00	20:50:33.65	-27:23:56.7	HIP 102848	6.38
2026-09-22 12:00	20:50:32.83	-27:23:57.4	HIP 102848	6.21
2026-09-23 00:00	20:50:32.02	-27:23:58.2	HIP 102848	6.04
2026-09-23 12:00	20:50:31.21	-27:23:58.9	HIP 102848	5.88
2026-09-24 00:00	20:50:30.42	-27:23:59.5	HIP 102848	5.72
2026-09-24 12:00	20:50:29.64	-27:24:00.1	HIP 102848	5.56
2026-09-25 00:00	20:50:28.86	-27:24:00.6	HIP 102848	5.41
2026-09-25 12:00	20:50:28.09	-27:24:01.1	HIP 102848	5.25
2026-09-26 00:00	20:50:27.34	-27:24:01.6	HIP 102848	5.10
2026-09-26 12:00	20:50:26.59	-27:24:02.0	HIP 102848	4.95
2026-09-27 00:00	20:50:25.85	-27:24:02.3	HIP 102848	4.81
2026-09-27 12:00	20:50:25.12	-27:24:02.6	HIP 102848	4.66
2026-09-28 00:00	20:50:24.39	-27:24:02.9	HIP 102848	4.52
2026-09-28 12:00	20:50:23.68	-27:24:03.1	HIP 102848	4.39
2026-09-29 00:00	20:50:22.98	-27:24:03.2	HIP 102848	4.25
2026-09-29 12:00	20:50:22.28	-27:24:03.3	HIP 102848	4.12
2026-09-30 00:00	20:50:21.60	-27:24:03.4	HIP 102848	3.99
2026-09-30 12:00	20:50:20.92	-27:24:03.4	HIP 102848	3.86
2026-10-01 00:00	20:50:20.26	-27:24:03.4	HIP 102848	3.74
2026-10-01 12:00	20:50:19.60	-27:24:03.3	HIP 102848	3.62
2026-10-02 00:00	20:50:18.95	-27:24:03.1	HIP 102848	3.50
2026-10-02 12:00	20:50:18.32	-27:24:03.0	HIP 102848	3.39
2026-10-03 00:00	20:50:17.69	-27:24:02.7	HIP 102848	3.28
2026-10-03 12:00	20:50:17.07	-27:24:02.4	HIP 102848	3.17
2026-10-04 00:00	20:50:16.46	-27:24:02.1	HIP 102848	3.07
2026-10-04 12:00	20:50:15.86	-27:24:01.7	HIP 102848	2.97
2026-10-05 00:00	20:50:15.27	-27:24:01.3	HIP 102848	2.87
2026-10-05 12:00	20:50:14.69	-27:24:00.8	HIP 102848	2.78
2026-10-06 00:00	20:50:14.13	-27:24:00.3	HIP 102848	2.69
2026-10-06 12:00	20:50:13.57	-27:23:59.7	HIP 102848	2.60
2026-10-07 00:00	20:50:13.02	-27:23:59.1	HIP 102848	2.52
2026-10-07 12:00	20:50:12.48	-27:23:58.4	HIP 102848	2.45
2026-10-08 00:00	20:50:11.95	-27:23:57.7	HIP 102848	2.37
2026-10-08 12:00	20:50:11.43	-27:23:57.0	HIP 102848	2.30
2026-10-09 00:00	20:50:10.92	-27:23:56.1	HIP 102848	2.24
2026-10-09 12:00	20:50:10.43	-27:23:55.3	HIP 102848	2.18
2026-10-10 00:00	20:50:09.94	-27:23:54.4	HIP 102848	2.12
2026-10-10 12:00	20:50:09.46	-27:23:53.4	HIP 102848	2.07
2026-10-11 00:00	20:50:08.99	-27:23:52.4	HIP 102845	2.01