446P/McNaught
| 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) |
| 2026-02-03 00:00 |
08:54:26.95 |
+26:44:04.1 |
HIP 43729 |
11.43 |
| 2026-02-03 12:00 |
08:54:10.35 |
+26:44:46.7 |
HIP 43729 |
10.93 |
| 2026-02-04 00:00 |
08:53:53.76 |
+26:45:28.7 |
HIP 43670 |
9.36 |
| 2026-02-04 12:00 |
08:53:37.19 |
+26:46:10.0 |
HIP 43670 |
9.08 |
| 2026-02-05 00:00 |
08:53:20.64 |
+26:46:50.8 |
HIP 43670 |
10.29 |
| 2026-02-05 12:00 |
08:53:04.11 |
+26:47:31.0 |
HIP 43670 |
12.55 |
| 2026-02-06 00:00 |
08:52:47.61 |
+26:48:10.6 |
HIP 43670 |
15.40 |
| 2026-02-06 12:00 |
08:52:31.12 |
+26:48:49.6 |
HIP 43670 |
18.56 |
| 2026-02-07 00:00 |
08:52:14.67 |
+26:49:27.9 |
HIP 43430 |
19.75 |
| 2026-02-07 12:00 |
08:51:58.25 |
+26:50:05.7 |
HIP 43430 |
16.09 |
| 2026-02-08 00:00 |
08:51:41.86 |
+26:50:42.8 |
HIP 43430 |
12.47 |
| 2026-02-08 12:00 |
08:51:25.50 |
+26:51:19.2 |
HIP 43430 |
8.94 |
| 2026-02-09 00:00 |
08:51:09.18 |
+26:51:55.1 |
HIP 43430 |
5.63 |
| 2026-02-09 12:00 |
08:50:52.89 |
+26:52:30.2 |
HIP 43430 |
3.26 |
| 2026-02-10 00:00 |
08:50:36.65 |
+26:53:04.8 |
HIP 43430 |
4.06 |
| 2026-02-10 12:00 |
08:50:20.45 |
+26:53:38.6 |
HIP 43430 |
7.01 |
| 2026-02-11 00:00 |
08:50:04.30 |
+26:54:11.8 |
HIP 43430 |
10.40 |
| 2026-02-11 12:00 |
08:49:48.19 |
+26:54:44.4 |
HIP 43430 |
13.91 |
| 2026-02-12 00:00 |
08:49:32.14 |
+26:55:16.2 |
HIP 43430 |
17.45 |
| 2026-02-12 12:00 |
08:49:16.13 |
+26:55:47.4 |
HIP 43430 |
21.00 |
| 2026-02-13 00:00 |
08:49:00.18 |
+26:56:17.9 |
HIP 43430 |
24.56 |
| 2026-02-13 12:00 |
08:48:44.28 |
+26:56:47.8 |
HIP 43127 |
25.31 |
| 2026-02-14 00:00 |
08:48:28.45 |
+26:57:16.9 |
HIP 43127 |
22.54 |
| 2026-02-14 12:00 |
08:48:12.67 |
+26:57:45.4 |
HIP 43127 |
20.04 |
| 2026-02-15 00:00 |
08:47:56.96 |
+26:58:13.1 |
HIP 43127 |
17.89 |
| 2026-02-15 12:00 |
08:47:41.31 |
+26:58:40.2 |
HIP 43127 |
16.24 |
| 2026-02-16 00:00 |
08:47:25.73 |
+26:59:06.5 |
HIP 43127 |
15.22 |
| 2026-02-16 12:00 |
08:47:10.22 |
+26:59:32.2 |
HIP 43127 |
14.96 |
| 2026-02-17 00:00 |
08:46:54.78 |
+26:59:57.1 |
HIP 43127 |
15.49 |
| 2026-02-17 12:00 |
08:46:39.41 |
+27:00:21.3 |
HIP 43127 |
16.72 |
| 2026-02-18 00:00 |
08:46:24.12 |
+27:00:44.8 |
HIP 43127 |
18.50 |
| 2026-02-18 12:00 |
08:46:08.90 |
+27:01:07.6 |
HIP 43052 |
20.12 |
| 2026-02-19 00:00 |
08:45:53.77 |
+27:01:29.7 |
HIP 43052 |
21.02 |
| 2026-02-19 12:00 |
08:45:38.71 |
+27:01:51.0 |
HIP 43052 |
22.39 |
| 2026-02-20 00:00 |
08:45:23.74 |
+27:02:11.6 |
HIP 42852 |
22.68 |
| 2026-02-20 12:00 |
08:45:08.86 |
+27:02:31.5 |
HIP 42852 |
19.69 |
| 2026-02-21 00:00 |
08:44:54.06 |
+27:02:50.6 |
HIP 42852 |
16.85 |
| 2026-02-21 12:00 |
08:44:39.35 |
+27:03:09.1 |
HIP 42852 |
14.23 |
| 2026-02-22 00:00 |
08:44:24.74 |
+27:03:26.8 |
HIP 42852 |
11.96 |
| 2026-02-22 12:00 |
08:44:10.21 |
+27:03:43.7 |
HIP 42852 |
10.27 |
| 2026-02-23 00:00 |
08:43:55.78 |
+27:04:00.0 |
HIP 42852 |
9.45 |
| 2026-02-23 12:00 |
08:43:41.45 |
+27:04:15.4 |
HIP 42852 |
9.69 |
| 2026-02-24 00:00 |
08:43:27.22 |
+27:04:30.2 |
HIP 42852 |
10.90 |