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)
2026-03-26 00:00	20:54:20.46	-27:02:01.7	HIP 103182	24.47
2026-03-26 12:00	20:54:21.26	-27:02:01.2	HIP 103182	24.47
2026-03-27 00:00	20:54:22.04	-27:02:00.7	HIP 103182	24.47
2026-03-27 12:00	20:54:22.82	-27:02:00.3	HIP 103182	24.46
2026-03-28 00:00	20:54:23.59	-27:02:00.0	HIP 103182	24.47
2026-03-28 12:00	20:54:24.35	-27:01:59.7	HIP 103182	24.47
2026-03-29 00:00	20:54:25.10	-27:01:59.4	HIP 103182	24.47
2026-03-29 12:00	20:54:25.84	-27:01:59.2	HIP 103182	24.48
2026-03-30 00:00	20:54:26.57	-27:01:59.1	HIP 103182	24.49
2026-03-30 12:00	20:54:27.29	-27:01:59.0	HIP 103182	24.50
2026-03-31 00:00	20:54:28.01	-27:01:58.9	HIP 103182	24.51
2026-03-31 12:00	20:54:28.71	-27:01:58.9	HIP 103182	24.53
2026-04-01 00:00	20:54:29.40	-27:01:58.9	HIP 103182	24.54
2026-04-01 12:00	20:54:30.09	-27:01:59.0	HIP 103182	24.56
2026-04-02 00:00	20:54:30.76	-27:01:59.2	HIP 103182	24.58
2026-04-02 12:00	20:54:31.43	-27:01:59.3	HIP 103182	24.60
2026-04-03 00:00	20:54:32.08	-27:01:59.6	HIP 103182	24.62
2026-04-03 12:00	20:54:32.73	-27:01:59.9	HIP 103182	24.64
2026-04-04 00:00	20:54:33.37	-27:02:00.2	HIP 103182	24.67
2026-04-04 12:00	20:54:33.99	-27:02:00.6	HIP 103182	24.69
2026-04-05 00:00	20:54:34.61	-27:02:01.0	HIP 103182	24.72
2026-04-05 12:00	20:54:35.22	-27:02:01.5	HIP 103182	24.75
2026-04-06 00:00	20:54:35.81	-27:02:02.0	HIP 103182	24.78
2026-04-06 12:00	20:54:36.40	-27:02:02.6	HIP 103182	24.81
2026-04-07 00:00	20:54:36.98	-27:02:03.2	HIP 103182	24.84
2026-04-07 12:00	20:54:37.55	-27:02:03.9	HIP 103182	24.87
2026-04-08 00:00	20:54:38.10	-27:02:04.6	HIP 103182	24.90
2026-04-08 12:00	20:54:38.65	-27:02:05.3	HIP 103182	24.94
2026-04-09 00:00	20:54:39.19	-27:02:06.2	HIP 103182	24.97
2026-04-09 12:00	20:54:39.72	-27:02:07.0	HIP 103182	25.01
2026-04-10 00:00	20:54:40.23	-27:02:07.9	HIP 103182	25.05
2026-04-10 12:00	20:54:40.74	-27:02:08.9	HIP 103182	25.08
2026-04-11 00:00	20:54:41.24	-27:02:09.9	HIP 103182	25.12
2026-04-11 12:00	20:54:41.72	-27:02:11.0	HIP 103182	25.16
2026-04-12 00:00	20:54:42.20	-27:02:12.1	HIP 103182	25.20
2026-04-12 12:00	20:54:42.66	-27:02:13.2	HIP 103182	25.24
2026-04-13 00:00	20:54:43.12	-27:02:14.4	HIP 103182	25.28
2026-04-13 12:00	20:54:43.57	-27:02:15.7	HIP 103182	25.33
2026-04-14 00:00	20:54:44.00	-27:02:17.0	HIP 103182	25.37
2026-04-14 12:00	20:54:44.42	-27:02:18.3	HIP 103182	25.41
2026-04-15 00:00	20:54:44.84	-27:02:19.7	HIP 103182	25.45
2026-04-15 12:00	20:54:45.24	-27:02:21.1	HIP 103182	25.50
2026-04-16 00:00	20:54:45.63	-27:02:22.6	HIP 103182	25.54