| Parameter |
Value |
| Designation |
446P/McNaught |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2012-08-14T16:28:43.587840Z |
| Orbit solution date (soln_date, UTC) |
2024-07-13T19:12:22Z |
| Obs used |
396 |
| NEO |
- |
| M1 |
17.500 |
| K1 |
6.750 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2015-01-08.0000000 |
| e |
0.64668523 |
| q (au) |
1.618504 |
| a (au) |
4.580911 |
| i (deg) |
16.571891 |
| Ω (om, deg) |
336.425077 |
| ω (w, deg) |
344.682612 |
| M (ma, deg) |
88.091854 |
Magnitude
Scatter + Global Linear
$$
M_a = (17.429 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
17.429 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.849 |
| k |
0.999 |
| 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) |
| 2026-03-26 00:00 |
08:33:01.85 |
+26:57:38.6 |
HIP 41999 |
24.42 |
| 2026-03-26 12:00 |
08:32:55.85 |
+26:57:11.6 |
HIP 41999 |
25.31 |
| 2026-03-27 00:00 |
08:32:50.01 |
+26:56:44.0 |
HIP 41999 |
26.24 |
| 2026-03-27 12:00 |
08:32:44.32 |
+26:56:15.8 |
HIP 41999 |
27.21 |
| 2026-03-28 00:00 |
08:32:38.79 |
+26:55:47.0 |
HIP 41999 |
28.19 |
| 2026-03-28 12:00 |
08:32:33.42 |
+26:55:17.6 |
HIP 41999 |
29.20 |
| 2026-03-29 00:00 |
08:32:28.21 |
+26:54:47.7 |
HIP 41999 |
30.21 |
| 2026-03-29 12:00 |
08:32:23.15 |
+26:54:17.2 |
HIP 41999 |
31.23 |
| 2026-03-30 00:00 |
08:32:18.25 |
+26:53:46.1 |
HIP 41999 |
32.26 |
| 2026-03-30 12:00 |
08:32:13.51 |
+26:53:14.5 |
HIP 41999 |
33.29 |
| 2026-03-31 00:00 |
08:32:08.92 |
+26:52:42.3 |
HIP 41999 |
34.31 |
| 2026-03-31 12:00 |
08:32:04.49 |
+26:52:09.5 |
HIP 41999 |
35.33 |
| 2026-04-01 00:00 |
08:32:00.22 |
+26:51:36.2 |
HIP 41999 |
36.34 |
| 2026-04-01 12:00 |
08:31:56.10 |
+26:51:02.4 |
HIP 41950 |
37.26 |
| 2026-04-02 00:00 |
08:31:52.15 |
+26:50:28.0 |
HIP 41950 |
37.11 |
| 2026-04-02 12:00 |
08:31:48.35 |
+26:49:53.1 |
HIP 41950 |
36.98 |
| 2026-04-03 00:00 |
08:31:44.70 |
+26:49:17.6 |
HIP 41950 |
36.84 |
| 2026-04-03 12:00 |
08:31:41.22 |
+26:48:41.6 |
HIP 41950 |
36.71 |
| 2026-04-04 00:00 |
08:31:37.89 |
+26:48:05.1 |
HIP 41950 |
36.58 |
| 2026-04-04 12:00 |
08:31:34.71 |
+26:47:28.1 |
HIP 41950 |
36.45 |
| 2026-04-05 00:00 |
08:31:31.70 |
+26:46:50.5 |
HIP 41950 |
36.31 |
| 2026-04-05 12:00 |
08:31:28.83 |
+26:46:12.4 |
HIP 41950 |
36.17 |
| 2026-04-06 00:00 |
08:31:26.13 |
+26:45:33.9 |
HIP 41950 |
36.02 |
| 2026-04-06 12:00 |
08:31:23.58 |
+26:44:54.8 |
HIP 41950 |
35.87 |
| 2026-04-07 00:00 |
08:31:21.19 |
+26:44:15.2 |
HIP 41950 |
35.70 |
| 2026-04-07 12:00 |
08:31:18.96 |
+26:43:35.1 |
HIP 41950 |
35.53 |
| 2026-04-08 00:00 |
08:31:16.88 |
+26:42:54.5 |
HIP 41950 |
35.35 |
| 2026-04-08 12:00 |
08:31:14.95 |
+26:42:13.4 |
HIP 41950 |
35.15 |
| 2026-04-09 00:00 |
08:31:13.18 |
+26:41:31.9 |
HIP 41950 |
34.94 |
| 2026-04-09 12:00 |
08:31:11.57 |
+26:40:49.8 |
HIP 41679 |
34.54 |
| 2026-04-10 00:00 |
08:31:10.11 |
+26:40:07.3 |
HIP 41679 |
33.77 |
| 2026-04-10 12:00 |
08:31:08.81 |
+26:39:24.2 |
HIP 41679 |
33.01 |
| 2026-04-11 00:00 |
08:31:07.66 |
+26:38:40.7 |
HIP 41679 |
32.26 |
| 2026-04-11 12:00 |
08:31:06.66 |
+26:37:56.8 |
HIP 41679 |
31.52 |
| 2026-04-12 00:00 |
08:31:05.82 |
+26:37:12.3 |
HIP 41679 |
30.80 |
| 2026-04-12 12:00 |
08:31:05.14 |
+26:36:27.4 |
HIP 41679 |
30.10 |
| 2026-04-13 00:00 |
08:31:04.61 |
+26:35:42.0 |
HIP 41679 |
29.41 |
| 2026-04-13 12:00 |
08:31:04.23 |
+26:34:56.2 |
HIP 41679 |
28.73 |
| 2026-04-14 00:00 |
08:31:04.00 |
+26:34:09.9 |
HIP 41679 |
28.08 |
| 2026-04-14 12:00 |
08:31:03.93 |
+26:33:23.2 |
HIP 41679 |
27.45 |
| 2026-04-15 00:00 |
08:31:04.01 |
+26:32:36.0 |
HIP 41679 |
26.84 |
| 2026-04-15 12:00 |
08:31:04.24 |
+26:31:48.3 |
HIP 41679 |
26.25 |
| 2026-04-16 00:00 |
08:31:04.62 |
+26:31:00.3 |
HIP 41679 |
25.70 |