| Parameter |
Value |
| Designation |
401P/McNaught |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2006-05-07T16:51:22.184640Z |
| Orbit solution date (soln_date, UTC) |
2024-06-03T15:49:51Z |
| Obs used |
268 |
| NEO |
- |
| M1 |
10.700 |
| K1 |
15.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2008-09-19.0000000 |
| e |
0.58200168 |
| q (au) |
2.379587 |
| a (au) |
5.692815 |
| i (deg) |
12.865037 |
| Ω (om, deg) |
0.095844 |
| ω (w, deg) |
310.243129 |
| M (ma, deg) |
62.788339 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.058 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.058 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.588 |
| k |
0.800 |
| 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 |
08:13:44.23 |
+31:18:24.4 |
HIP 40398 |
14.48 |
| 2026-03-26 12:00 |
08:13:40.43 |
+31:17:53.4 |
HIP 40398 |
15.28 |
| 2026-03-27 00:00 |
08:13:36.77 |
+31:17:22.0 |
HIP 40398 |
16.06 |
| 2026-03-27 12:00 |
08:13:33.24 |
+31:16:50.1 |
HIP 40398 |
16.83 |
| 2026-03-28 00:00 |
08:13:29.83 |
+31:16:17.8 |
HIP 40398 |
17.59 |
| 2026-03-28 12:00 |
08:13:26.56 |
+31:15:45.1 |
HIP 40398 |
18.34 |
| 2026-03-29 00:00 |
08:13:23.41 |
+31:15:11.9 |
HIP 40398 |
19.07 |
| 2026-03-29 12:00 |
08:13:20.40 |
+31:14:38.3 |
HIP 40398 |
19.79 |
| 2026-03-30 00:00 |
08:13:17.51 |
+31:14:04.3 |
HIP 40398 |
20.49 |
| 2026-03-30 12:00 |
08:13:14.75 |
+31:13:29.9 |
HIP 40398 |
21.18 |
| 2026-03-31 00:00 |
08:13:12.13 |
+31:12:55.1 |
HIP 40398 |
21.85 |
| 2026-03-31 12:00 |
08:13:09.63 |
+31:12:19.8 |
HIP 40103 |
21.89 |
| 2026-04-01 00:00 |
08:13:07.26 |
+31:11:44.1 |
HIP 40103 |
21.58 |
| 2026-04-01 12:00 |
08:13:05.02 |
+31:11:08.1 |
HIP 40103 |
21.32 |
| 2026-04-02 00:00 |
08:13:02.91 |
+31:10:31.6 |
HIP 40103 |
21.11 |
| 2026-04-02 12:00 |
08:13:00.92 |
+31:09:54.7 |
HIP 40103 |
20.95 |
| 2026-04-03 00:00 |
08:12:59.07 |
+31:09:17.5 |
HIP 40103 |
20.85 |
| 2026-04-03 12:00 |
08:12:57.35 |
+31:08:39.8 |
HIP 40103 |
20.80 |
| 2026-04-04 00:00 |
08:12:55.75 |
+31:08:01.8 |
HIP 40103 |
20.81 |
| 2026-04-04 12:00 |
08:12:54.29 |
+31:07:23.4 |
HIP 40103 |
20.86 |
| 2026-04-05 00:00 |
08:12:52.95 |
+31:06:44.6 |
HIP 40103 |
20.97 |
| 2026-04-05 12:00 |
08:12:51.74 |
+31:06:05.4 |
HIP 40103 |
21.12 |
| 2026-04-06 00:00 |
08:12:50.66 |
+31:05:25.9 |
HIP 40103 |
21.33 |
| 2026-04-06 12:00 |
08:12:49.71 |
+31:04:46.0 |
HIP 40103 |
21.57 |
| 2026-04-07 00:00 |
08:12:48.88 |
+31:04:05.7 |
HIP 40103 |
21.87 |
| 2026-04-07 12:00 |
08:12:48.19 |
+31:03:25.1 |
HIP 40103 |
22.20 |
| 2026-04-08 00:00 |
08:12:47.62 |
+31:02:44.1 |
HIP 40103 |
22.58 |
| 2026-04-08 12:00 |
08:12:47.18 |
+31:02:02.7 |
HIP 40103 |
22.99 |
| 2026-04-09 00:00 |
08:12:46.87 |
+31:01:21.0 |
HIP 40103 |
23.44 |
| 2026-04-09 12:00 |
08:12:46.69 |
+31:00:39.0 |
HIP 40103 |
23.93 |
| 2026-04-10 00:00 |
08:12:46.63 |
+30:59:56.6 |
HIP 40103 |
24.44 |
| 2026-04-10 12:00 |
08:12:46.70 |
+30:59:13.8 |
HIP 40103 |
24.99 |
| 2026-04-11 00:00 |
08:12:46.90 |
+30:58:30.7 |
HIP 40103 |
25.57 |
| 2026-04-11 12:00 |
08:12:47.23 |
+30:57:47.3 |
HIP 40103 |
26.18 |
| 2026-04-12 00:00 |
08:12:47.68 |
+30:57:03.6 |
HIP 40103 |
26.81 |
| 2026-04-12 12:00 |
08:12:48.26 |
+30:56:19.5 |
HIP 40103 |
27.47 |
| 2026-04-13 00:00 |
08:12:48.96 |
+30:55:35.0 |
HIP 40103 |
28.16 |
| 2026-04-13 12:00 |
08:12:49.79 |
+30:54:50.3 |
HIP 40226 |
28.29 |
| 2026-04-14 00:00 |
08:12:50.75 |
+30:54:05.2 |
HIP 40226 |
27.53 |
| 2026-04-14 12:00 |
08:12:51.84 |
+30:53:19.9 |
HIP 40226 |
26.76 |
| 2026-04-15 00:00 |
08:12:53.05 |
+30:52:34.2 |
HIP 40226 |
25.99 |
| 2026-04-15 12:00 |
08:12:54.38 |
+30:51:48.1 |
HIP 40226 |
25.22 |
| 2026-04-16 00:00 |
08:12:55.84 |
+30:51:01.8 |
HIP 40226 |
24.44 |