C/1991 Q1 (McNaught-Russell)

Metadata

Parameter Value
Designation C/1991 Q1 (McNaught-Russell)
Type C
Perihelion (tp_cal, UTC) 1992-05-03T10:52:23.122560Z
Orbit solution date (soln_date, UTC) 2021-04-15T23:29:41Z
Obs used 29
NEO -
M1 5.000
K1 15.500
PC 0.030
Osculating Elements
Parameter Value
Epoch (epoch_cal, TDB) 1992-08-12.0000000
e 0.99448867
q (au) 3.193967
a (au) 579.527657
i (deg) 90.506206
Ω (om, deg) 120.462895
ω (w, deg) 257.232969
M (ma, deg) 0.007103

Magnitude

C/1991 Q1 (McNaught-Russell) · Magnitude (Full range)

Scatter + Global Linear

$$ M_a = (13.014 + 2.500\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$

Model Parameters

Parameter Value
H0 13.014
n 2.500
gf 1.000
gb -0.876
k 0.968
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

Ephemeris

Date/Time (UTC) RA (J2000) Dec (J2000) Nearest HIP Dist from HIP (arcmin)
2026-05-12 00:00 09:38:45.19 +67:55:18.5 HIP 47348 5.57
2026-05-12 12:00 09:38:45.16 +67:54:54.5 HIP 47348 5.97
2026-05-13 00:00 09:38:45.17 +67:54:30.4 HIP 47348 6.37
2026-05-13 12:00 09:38:45.22 +67:54:06.3 HIP 47348 6.77
2026-05-14 00:00 09:38:45.32 +67:53:42.1 HIP 47348 7.17
2026-05-14 12:00 09:38:45.46 +67:53:17.9 HIP 47348 7.57
2026-05-15 00:00 09:38:45.65 +67:52:53.6 HIP 47348 7.97
2026-05-15 12:00 09:38:45.88 +67:52:29.3 HIP 47348 8.38
2026-05-16 00:00 09:38:46.16 +67:52:05.0 HIP 47348 8.78
2026-05-16 12:00 09:38:46.48 +67:51:40.6 HIP 47348 9.18
2026-05-17 00:00 09:38:46.85 +67:51:16.2 HIP 47348 9.59
2026-05-17 12:00 09:38:47.27 +67:50:51.8 HIP 47348 10.00
2026-05-18 00:00 09:38:47.72 +67:50:27.3 HIP 47348 10.40
2026-05-18 12:00 09:38:48.22 +67:50:02.8 HIP 47348 10.81
2026-05-19 00:00 09:38:48.77 +67:49:38.3 HIP 47348 11.22
2026-05-19 12:00 09:38:49.36 +67:49:13.7 HIP 47348 11.62
2026-05-20 00:00 09:38:50.00 +67:48:49.1 HIP 47348 12.03
2026-05-20 12:00 09:38:50.67 +67:48:24.5 HIP 47348 12.44
2026-05-21 00:00 09:38:51.40 +67:47:59.9 HIP 47348 12.85
2026-05-21 12:00 09:38:52.16 +67:47:35.3 HIP 47348 13.27
2026-05-22 00:00 09:38:52.97 +67:47:10.6 HIP 47348 13.68
2026-05-22 12:00 09:38:53.83 +67:46:45.9 HIP 47348 14.09
2026-05-23 00:00 09:38:54.72 +67:46:21.3 HIP 47348 14.50
2026-05-23 12:00 09:38:55.66 +67:45:56.6 HIP 47348 14.92
2026-05-24 00:00 09:38:56.65 +67:45:31.9 HIP 47348 15.33
2026-05-24 12:00 09:38:57.67 +67:45:07.2 HIP 47348 15.75
2026-05-25 00:00 09:38:58.74 +67:44:42.5 HIP 47348 16.16
2026-05-25 12:00 09:38:59.85 +67:44:17.8 HIP 47348 16.58
2026-05-26 00:00 09:39:01.01 +67:43:53.1 HIP 47348 16.99
2026-05-26 12:00 09:39:02.20 +67:43:28.3 HIP 47348 17.41
2026-05-27 00:00 09:39:03.44 +67:43:03.6 HIP 47348 17.83
2026-05-27 12:00 09:39:04.72 +67:42:38.9 HIP 47348 18.25
2026-05-28 00:00 09:39:06.04 +67:42:14.2 HIP 47348 18.67
2026-05-28 12:00 09:39:07.41 +67:41:49.5 HIP 47348 19.09
2026-05-29 00:00 09:39:08.81 +67:41:24.9 HIP 47348 19.51
2026-05-29 12:00 09:39:10.26 +67:41:00.2 HIP 47348 19.93
2026-05-30 00:00 09:39:11.74 +67:40:35.5 HIP 47348 20.36
2026-05-30 12:00 09:39:13.27 +67:40:10.9 HIP 47348 20.78
2026-05-31 00:00 09:39:14.84 +67:39:46.2 HIP 47348 21.20
2026-05-31 12:00 09:39:16.45 +67:39:21.6 HIP 47348 21.63
2026-06-01 00:00 09:39:18.10 +67:38:57.0 HIP 47348 22.05
2026-06-01 12:00 09:39:19.79 +67:38:32.5 HIP 47401 22.22
2026-06-02 00:00 09:39:21.53 +67:38:07.9 HIP 47401 21.80