| 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) |
| 2026-07-29 00:00 |
09:10:14.62 |
+22:09:15.1 |
HIP 45033 |
9.58 |
| 2026-07-29 12:00 |
09:10:31.60 |
+22:07:46.9 |
HIP 45033 |
8.37 |
| 2026-07-30 00:00 |
09:10:48.58 |
+22:06:18.6 |
HIP 45033 |
9.16 |
| 2026-07-30 12:00 |
09:11:05.57 |
+22:04:50.4 |
HIP 45033 |
11.53 |
| 2026-07-31 00:00 |
09:11:22.57 |
+22:03:22.2 |
HIP 45033 |
14.74 |
| 2026-07-31 12:00 |
09:11:39.57 |
+22:01:54.1 |
HIP 45033 |
18.37 |
| 2026-08-01 00:00 |
09:11:56.58 |
+22:00:25.9 |
HIP 45033 |
22.20 |
| 2026-08-01 12:00 |
09:12:13.59 |
+21:58:57.8 |
HIP 45033 |
26.15 |
| 2026-08-02 00:00 |
09:12:30.60 |
+21:57:29.7 |
HIP 45033 |
30.17 |
| 2026-08-02 12:00 |
09:12:47.62 |
+21:56:01.6 |
HIP 45033 |
34.24 |
| 2026-08-03 00:00 |
09:13:04.65 |
+21:54:33.6 |
HIP 45272 |
38.32 |
| 2026-08-03 12:00 |
09:13:21.67 |
+21:53:05.6 |
HIP 45272 |
36.28 |
| 2026-08-04 00:00 |
09:13:38.70 |
+21:51:37.6 |
HIP 45272 |
34.63 |
| 2026-08-04 12:00 |
09:13:55.73 |
+21:50:09.7 |
HIP 45272 |
33.44 |
| 2026-08-05 00:00 |
09:14:12.76 |
+21:48:41.8 |
HIP 45272 |
32.76 |
| 2026-08-05 12:00 |
09:14:29.79 |
+21:47:14.0 |
HIP 45272 |
32.61 |
| 2026-08-06 00:00 |
09:14:46.81 |
+21:45:46.2 |
HIP 45272 |
33.01 |
| 2026-08-06 12:00 |
09:15:03.84 |
+21:44:18.4 |
HIP 45473 |
30.37 |
| 2026-08-07 00:00 |
09:15:20.87 |
+21:42:50.7 |
HIP 45473 |
27.52 |
| 2026-08-07 12:00 |
09:15:37.89 |
+21:41:23.1 |
HIP 45473 |
25.07 |
| 2026-08-08 00:00 |
09:15:54.92 |
+21:39:55.5 |
HIP 45473 |
23.13 |
| 2026-08-08 12:00 |
09:16:11.94 |
+21:38:28.0 |
HIP 45473 |
21.85 |
| 2026-08-09 00:00 |
09:16:28.95 |
+21:37:00.5 |
HIP 45611 |
21.22 |
| 2026-08-09 12:00 |
09:16:45.96 |
+21:35:33.1 |
HIP 45611 |
18.67 |
| 2026-08-10 00:00 |
09:17:02.97 |
+21:34:05.7 |
HIP 45611 |
16.80 |
| 2026-08-10 12:00 |
09:17:19.96 |
+21:32:38.5 |
HIP 45611 |
15.85 |
| 2026-08-11 00:00 |
09:17:36.96 |
+21:31:11.3 |
HIP 45611 |
15.99 |
| 2026-08-11 12:00 |
09:17:53.94 |
+21:29:44.2 |
HIP 45611 |
17.19 |
| 2026-08-12 00:00 |
09:18:10.92 |
+21:28:17.1 |
HIP 45611 |
19.25 |
| 2026-08-12 12:00 |
09:18:27.89 |
+21:26:50.2 |
HIP 45611 |
21.93 |
| 2026-08-13 00:00 |
09:18:44.85 |
+21:25:23.3 |
HIP 45611 |
25.03 |
| 2026-08-13 12:00 |
09:19:01.80 |
+21:23:56.5 |
HIP 45611 |
28.41 |
| 2026-08-14 00:00 |
09:19:18.73 |
+21:22:29.8 |
HIP 45844 |
27.41 |
| 2026-08-14 12:00 |
09:19:35.66 |
+21:21:03.3 |
HIP 45844 |
25.62 |
| 2026-08-15 00:00 |
09:19:52.57 |
+21:19:36.8 |
HIP 45844 |
24.42 |
| 2026-08-15 12:00 |
09:20:09.48 |
+21:18:10.4 |
HIP 45844 |
23.91 |
| 2026-08-16 00:00 |
09:20:26.36 |
+21:16:44.1 |
HIP 45844 |
24.12 |
| 2026-08-16 12:00 |
09:20:43.24 |
+21:15:17.9 |
HIP 45936 |
22.96 |
| 2026-08-17 00:00 |
09:21:00.10 |
+21:13:51.9 |
HIP 45936 |
21.16 |
| 2026-08-17 12:00 |
09:21:16.94 |
+21:12:25.9 |
HIP 45936 |
20.07 |
| 2026-08-18 00:00 |
09:21:33.77 |
+21:11:00.1 |
HIP 45936 |
19.83 |
| 2026-08-18 12:00 |
09:21:50.58 |
+21:09:34.4 |
HIP 45936 |
20.44 |
| 2026-08-19 00:00 |
09:22:07.38 |
+21:08:08.8 |
HIP 46038 |
20.39 |