320P/McNaught
| Parameter |
Value |
| Designation |
320P/McNaught |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2010-02-21T01:58:51.620160Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:28:23Z |
| Obs used |
121 |
| NEO |
Yes |
| M1 |
19.600 |
| K1 |
14.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2011-04-07.0000000 |
| e |
0.68244389 |
| q (au) |
0.985360 |
| a (au) |
3.102949 |
| i (deg) |
4.893564 |
| Ω (om, deg) |
295.955979 |
| ω (w, deg) |
0.665974 |
| M (ma, deg) |
73.916022 |
Magnitude
Scatter + Global Linear
$$
M_a = (20.000 + 5.332\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
20.000 |
| n |
5.332 |
| gf |
1.000 |
| gb |
-0.745 |
| k |
0.981 |
| 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 |
14:17:55.18 |
-19:45:53.9 |
HIP 69828 |
13.56 |
| 2026-02-03 12:00 |
14:18:42.82 |
-19:51:23.9 |
HIP 69908 |
18.08 |
| 2026-02-04 00:00 |
14:19:30.54 |
-19:56:54.2 |
HIP 69908 |
27.66 |
| 2026-02-04 12:00 |
14:20:18.32 |
-20:02:24.8 |
HIP 70177 |
27.39 |
| 2026-02-05 00:00 |
14:21:06.18 |
-20:07:55.8 |
HIP 70177 |
27.69 |
| 2026-02-05 12:00 |
14:21:54.11 |
-20:13:27.1 |
HIP 70177 |
33.14 |
| 2026-02-06 00:00 |
14:22:42.11 |
-20:18:58.8 |
HIP 70261 |
26.54 |
| 2026-02-06 12:00 |
14:23:30.18 |
-20:24:30.8 |
HIP 70482 |
22.86 |
| 2026-02-07 00:00 |
14:24:18.33 |
-20:30:03.1 |
HIP 70482 |
10.34 |
| 2026-02-07 12:00 |
14:25:06.55 |
-20:35:35.8 |
HIP 70482 |
2.63 |
| 2026-02-08 00:00 |
14:25:54.85 |
-20:41:08.9 |
HIP 70482 |
14.96 |
| 2026-02-08 12:00 |
14:26:43.22 |
-20:46:42.3 |
HIP 70765 |
25.61 |
| 2026-02-09 00:00 |
14:27:31.68 |
-20:52:16.1 |
HIP 70765 |
21.34 |
| 2026-02-09 12:00 |
14:28:20.21 |
-20:57:50.3 |
HIP 70765 |
23.97 |
| 2026-02-10 00:00 |
14:29:08.82 |
-21:03:24.9 |
HIP 70961 |
31.51 |
| 2026-02-10 12:00 |
14:29:57.51 |
-21:08:59.8 |
HIP 70932 |
21.80 |
| 2026-02-11 00:00 |
14:30:46.29 |
-21:14:35.1 |
HIP 70932 |
16.10 |
| 2026-02-11 12:00 |
14:31:35.14 |
-21:20:10.9 |
HIP 70932 |
19.09 |
| 2026-02-12 00:00 |
14:32:24.08 |
-21:25:47.0 |
HIP 70932 |
28.12 |
| 2026-02-12 12:00 |
14:33:13.11 |
-21:31:23.6 |
HIP 71071 |
38.28 |
| 2026-02-13 00:00 |
14:34:02.22 |
-21:37:00.6 |
HIP 71407 |
44.49 |
| 2026-02-13 12:00 |
14:34:51.41 |
-21:42:37.9 |
HIP 71407 |
33.13 |
| 2026-02-14 00:00 |
14:35:40.70 |
-21:48:15.8 |
HIP 71407 |
23.24 |
| 2026-02-14 12:00 |
14:36:30.07 |
-21:53:54.0 |
HIP 71473 |
16.33 |
| 2026-02-15 00:00 |
14:37:19.54 |
-21:59:32.7 |
HIP 71473 |
9.67 |
| 2026-02-15 12:00 |
14:38:09.10 |
-22:05:11.9 |
HIP 71473 |
15.72 |
| 2026-02-16 00:00 |
14:38:58.75 |
-22:10:51.5 |
HIP 71621 |
8.89 |
| 2026-02-16 12:00 |
14:39:48.50 |
-22:16:31.6 |
HIP 71621 |
12.86 |
| 2026-02-17 00:00 |
14:40:38.34 |
-22:22:12.2 |
HIP 71792 |
16.29 |
| 2026-02-17 12:00 |
14:41:28.29 |
-22:27:53.2 |
HIP 71792 |
10.48 |
| 2026-02-18 00:00 |
14:42:18.33 |
-22:33:34.8 |
HIP 71792 |
16.90 |
| 2026-02-18 12:00 |
14:43:08.48 |
-22:39:16.8 |
HIP 71992 |
22.01 |
| 2026-02-19 00:00 |
14:43:58.73 |
-22:44:59.4 |
HIP 71992 |
17.86 |
| 2026-02-19 12:00 |
14:44:49.09 |
-22:50:42.5 |
HIP 71992 |
22.08 |
| 2026-02-20 00:00 |
14:45:39.55 |
-22:56:26.1 |
HIP 72210 |
14.19 |
| 2026-02-20 12:00 |
14:46:30.13 |
-23:02:10.3 |
HIP 72210 |
8.83 |
| 2026-02-21 00:00 |
14:47:20.82 |
-23:07:55.1 |
HIP 72210 |
17.07 |
| 2026-02-21 12:00 |
14:48:11.63 |
-23:13:40.4 |
HIP 72210 |
29.05 |
| 2026-02-22 00:00 |
14:49:02.56 |
-23:19:26.3 |
HIP 72210 |
41.67 |
| 2026-02-22 12:00 |
14:49:53.61 |
-23:25:12.8 |
HIP 72652 |
32.32 |
| 2026-02-23 00:00 |
14:50:44.79 |
-23:30:59.9 |
HIP 72652 |
21.72 |
| 2026-02-23 12:00 |
14:51:36.09 |
-23:36:47.6 |
HIP 72652 |
15.51 |
| 2026-02-24 00:00 |
14:52:27.52 |
-23:42:36.0 |
HIP 72839 |
18.54 |