| Parameter |
Value |
| Designation |
C/2009 F5 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2008-11-04T19:50:20.624640Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:30Z |
| Obs used |
444 |
| NEO |
- |
| M1 |
12.800 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2009-05-07.0000000 |
| e |
0.97199145 |
| q (au) |
2.245337 |
| a (au) |
80.166145 |
| i (deg) |
84.990355 |
| Ω (om, deg) |
219.064143 |
| ω (w, deg) |
297.366826 |
| M (ma, deg) |
0.251524 |
Magnitude
Scatter + Global Linear
$$
M_a = (14.104 + 2.537\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
14.104 |
| n |
2.537 |
| gf |
1.000 |
| gb |
-0.637 |
| 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) |
| 2026-09-20 00:00 |
18:20:29.35 |
+63:19:34.3 |
HIP 89796 |
9.57 |
| 2026-09-20 12:00 |
18:20:28.88 |
+63:18:45.1 |
HIP 89796 |
8.94 |
| 2026-09-21 00:00 |
18:20:28.46 |
+63:17:55.7 |
HIP 89796 |
8.35 |
| 2026-09-21 12:00 |
18:20:28.12 |
+63:17:06.4 |
HIP 89796 |
7.81 |
| 2026-09-22 00:00 |
18:20:27.84 |
+63:16:17.0 |
HIP 89796 |
7.33 |
| 2026-09-22 12:00 |
18:20:27.62 |
+63:15:27.5 |
HIP 89796 |
6.92 |
| 2026-09-23 00:00 |
18:20:27.47 |
+63:14:38.0 |
HIP 89796 |
6.59 |
| 2026-09-23 12:00 |
18:20:27.38 |
+63:13:48.5 |
HIP 89796 |
6.36 |
| 2026-09-24 00:00 |
18:20:27.36 |
+63:12:59.0 |
HIP 89796 |
6.24 |
| 2026-09-24 12:00 |
18:20:27.40 |
+63:12:09.4 |
HIP 89796 |
6.24 |
| 2026-09-25 00:00 |
18:20:27.51 |
+63:11:19.8 |
HIP 89796 |
6.35 |
| 2026-09-25 12:00 |
18:20:27.68 |
+63:10:30.2 |
HIP 89796 |
6.57 |
| 2026-09-26 00:00 |
18:20:27.92 |
+63:09:40.6 |
HIP 89796 |
6.89 |
| 2026-09-26 12:00 |
18:20:28.22 |
+63:08:51.0 |
HIP 89796 |
7.30 |
| 2026-09-27 00:00 |
18:20:28.59 |
+63:08:01.4 |
HIP 89796 |
7.78 |
| 2026-09-27 12:00 |
18:20:29.02 |
+63:07:11.8 |
HIP 89796 |
8.32 |
| 2026-09-28 00:00 |
18:20:29.51 |
+63:06:22.2 |
HIP 89796 |
8.91 |
| 2026-09-28 12:00 |
18:20:30.07 |
+63:05:32.6 |
HIP 89919 |
8.65 |
| 2026-09-29 00:00 |
18:20:30.69 |
+63:04:43.0 |
HIP 89919 |
7.84 |
| 2026-09-29 12:00 |
18:20:31.38 |
+63:03:53.4 |
HIP 89919 |
7.04 |
| 2026-09-30 00:00 |
18:20:32.13 |
+63:03:03.8 |
HIP 89919 |
6.24 |
| 2026-09-30 12:00 |
18:20:32.95 |
+63:02:14.2 |
HIP 89919 |
5.45 |
| 2026-10-01 00:00 |
18:20:33.82 |
+63:01:24.7 |
HIP 89919 |
4.67 |
| 2026-10-01 12:00 |
18:20:34.77 |
+63:00:35.2 |
HIP 89919 |
3.90 |
| 2026-10-02 00:00 |
18:20:35.77 |
+62:59:45.7 |
HIP 89919 |
3.17 |
| 2026-10-02 12:00 |
18:20:36.84 |
+62:58:56.3 |
HIP 89919 |
2.50 |
| 2026-10-03 00:00 |
18:20:37.98 |
+62:58:06.9 |
HIP 89919 |
1.94 |
| 2026-10-03 12:00 |
18:20:39.17 |
+62:57:17.5 |
HIP 89919 |
1.63 |
| 2026-10-04 00:00 |
18:20:40.43 |
+62:56:28.2 |
HIP 89919 |
1.71 |
| 2026-10-04 12:00 |
18:20:41.76 |
+62:55:38.9 |
HIP 89919 |
2.14 |
| 2026-10-05 00:00 |
18:20:43.14 |
+62:54:49.7 |
HIP 89919 |
2.75 |
| 2026-10-05 12:00 |
18:20:44.59 |
+62:54:00.5 |
HIP 89919 |
3.46 |
| 2026-10-06 00:00 |
18:20:46.10 |
+62:53:11.4 |
HIP 89919 |
4.21 |
| 2026-10-06 12:00 |
18:20:47.68 |
+62:52:22.3 |
HIP 89919 |
4.99 |
| 2026-10-07 00:00 |
18:20:49.32 |
+62:51:33.4 |
HIP 89919 |
5.78 |
| 2026-10-07 12:00 |
18:20:51.02 |
+62:50:44.5 |
HIP 89919 |
6.58 |
| 2026-10-08 00:00 |
18:20:52.78 |
+62:49:55.6 |
HIP 89919 |
7.39 |
| 2026-10-08 12:00 |
18:20:54.61 |
+62:49:06.9 |
HIP 89919 |
8.20 |
| 2026-10-09 00:00 |
18:20:56.50 |
+62:48:18.2 |
HIP 89919 |
9.02 |
| 2026-10-09 12:00 |
18:20:58.45 |
+62:47:29.6 |
HIP 89919 |
9.84 |
| 2026-10-10 00:00 |
18:21:00.46 |
+62:46:41.1 |
HIP 89919 |
10.66 |
| 2026-10-10 12:00 |
18:21:02.53 |
+62:45:52.7 |
HIP 89919 |
11.48 |
| 2026-10-11 00:00 |
18:21:04.67 |
+62:45:04.4 |
HIP 89919 |
12.31 |