C/1991 Q1 (McNaught-Russell)
| 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
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) |
| 2026-02-03 00:00 |
09:50:46.34 |
+68:23:58.4 |
HIP 47838 |
36.30 |
| 2026-02-03 12:00 |
09:50:40.97 |
+68:24:11.3 |
HIP 47838 |
35.76 |
| 2026-02-04 00:00 |
09:50:35.58 |
+68:24:24.0 |
HIP 47838 |
35.23 |
| 2026-02-04 12:00 |
09:50:30.19 |
+68:24:36.5 |
HIP 47838 |
34.70 |
| 2026-02-05 00:00 |
09:50:24.78 |
+68:24:48.7 |
HIP 47838 |
34.17 |
| 2026-02-05 12:00 |
09:50:19.37 |
+68:25:00.7 |
HIP 47838 |
33.64 |
| 2026-02-06 00:00 |
09:50:13.95 |
+68:25:12.5 |
HIP 47838 |
33.11 |
| 2026-02-06 12:00 |
09:50:08.52 |
+68:25:24.0 |
HIP 47838 |
32.58 |
| 2026-02-07 00:00 |
09:50:03.08 |
+68:25:35.3 |
HIP 47838 |
32.06 |
| 2026-02-07 12:00 |
09:49:57.63 |
+68:25:46.4 |
HIP 47838 |
31.54 |
| 2026-02-08 00:00 |
09:49:52.18 |
+68:25:57.2 |
HIP 47838 |
31.02 |
| 2026-02-08 12:00 |
09:49:46.72 |
+68:26:07.8 |
HIP 47838 |
30.50 |
| 2026-02-09 00:00 |
09:49:41.25 |
+68:26:18.1 |
HIP 47838 |
29.98 |
| 2026-02-09 12:00 |
09:49:35.78 |
+68:26:28.2 |
HIP 47838 |
29.47 |
| 2026-02-10 00:00 |
09:49:30.30 |
+68:26:38.1 |
HIP 47838 |
28.96 |
| 2026-02-10 12:00 |
09:49:24.82 |
+68:26:47.7 |
HIP 47838 |
28.45 |
| 2026-02-11 00:00 |
09:49:19.34 |
+68:26:57.0 |
HIP 47838 |
27.94 |
| 2026-02-11 12:00 |
09:49:13.85 |
+68:27:06.1 |
HIP 47838 |
27.44 |
| 2026-02-12 00:00 |
09:49:08.36 |
+68:27:15.0 |
HIP 47838 |
26.94 |
| 2026-02-12 12:00 |
09:49:02.87 |
+68:27:23.6 |
HIP 47838 |
26.44 |
| 2026-02-13 00:00 |
09:48:57.37 |
+68:27:32.0 |
HIP 47838 |
25.95 |
| 2026-02-13 12:00 |
09:48:51.87 |
+68:27:40.1 |
HIP 47838 |
25.46 |
| 2026-02-14 00:00 |
09:48:46.38 |
+68:27:48.0 |
HIP 47838 |
24.97 |
| 2026-02-14 12:00 |
09:48:40.88 |
+68:27:55.6 |
HIP 47838 |
24.49 |
| 2026-02-15 00:00 |
09:48:35.38 |
+68:28:03.0 |
HIP 47838 |
24.01 |
| 2026-02-15 12:00 |
09:48:29.88 |
+68:28:10.2 |
HIP 47838 |
23.53 |
| 2026-02-16 00:00 |
09:48:24.39 |
+68:28:17.0 |
HIP 47838 |
23.06 |
| 2026-02-16 12:00 |
09:48:18.89 |
+68:28:23.7 |
HIP 47838 |
22.60 |
| 2026-02-17 00:00 |
09:48:13.40 |
+68:28:30.1 |
HIP 47838 |
22.14 |
| 2026-02-17 12:00 |
09:48:07.91 |
+68:28:36.2 |
HIP 47838 |
21.68 |
| 2026-02-18 00:00 |
09:48:02.42 |
+68:28:42.1 |
HIP 47838 |
21.23 |
| 2026-02-18 12:00 |
09:47:56.94 |
+68:28:47.7 |
HIP 47838 |
20.79 |
| 2026-02-19 00:00 |
09:47:51.46 |
+68:28:53.1 |
HIP 47838 |
20.35 |
| 2026-02-19 12:00 |
09:47:45.99 |
+68:28:58.2 |
HIP 47838 |
19.92 |
| 2026-02-20 00:00 |
09:47:40.52 |
+68:29:03.1 |
HIP 47838 |
19.49 |
| 2026-02-20 12:00 |
09:47:35.06 |
+68:29:07.7 |
HIP 47838 |
19.08 |
| 2026-02-21 00:00 |
09:47:29.60 |
+68:29:12.0 |
HIP 47838 |
18.67 |
| 2026-02-21 12:00 |
09:47:24.15 |
+68:29:16.2 |
HIP 47838 |
18.27 |
| 2026-02-22 00:00 |
09:47:18.71 |
+68:29:20.0 |
HIP 47838 |
17.87 |
| 2026-02-22 12:00 |
09:47:13.28 |
+68:29:23.6 |
HIP 47838 |
17.49 |
| 2026-02-23 00:00 |
09:47:07.85 |
+68:29:27.0 |
HIP 47838 |
17.12 |
| 2026-02-23 12:00 |
09:47:02.44 |
+68:29:30.1 |
HIP 47838 |
16.75 |
| 2026-02-24 00:00 |
09:46:57.03 |
+68:29:32.9 |
HIP 47838 |
16.40 |