| Parameter |
Value |
| Designation |
C/2009 F2 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2009-11-14T02:40:43.518720Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:29Z |
| Obs used |
363 |
| NEO |
- |
| M1 |
6.400 |
| K1 |
10.000 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2010-07-09.0000000 |
| e |
0.98302695 |
| q (au) |
5.875026 |
| a (au) |
346.138419 |
| i (deg) |
59.366975 |
| Ω (om, deg) |
214.055338 |
| ω (w, deg) |
336.344497 |
| M (ma, deg) |
0.036255 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.300 + 2.109\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.300 |
| n |
2.109 |
| gf |
1.000 |
| gb |
-0.969 |
| k |
1.000 |
| 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 |
20:42:33.63 |
+42:05:45.6 |
HIP 102321 |
16.58 |
| 2026-09-20 12:00 |
20:42:31.02 |
+42:05:03.6 |
HIP 102321 |
17.34 |
| 2026-09-21 00:00 |
20:42:28.45 |
+42:04:21.4 |
HIP 102321 |
18.09 |
| 2026-09-21 12:00 |
20:42:25.91 |
+42:03:39.0 |
HIP 102321 |
18.86 |
| 2026-09-22 00:00 |
20:42:23.40 |
+42:02:56.3 |
HIP 102321 |
19.62 |
| 2026-09-22 12:00 |
20:42:20.92 |
+42:02:13.5 |
HIP 102155 |
19.74 |
| 2026-09-23 00:00 |
20:42:18.48 |
+42:01:30.4 |
HIP 102155 |
18.94 |
| 2026-09-23 12:00 |
20:42:16.07 |
+42:00:47.1 |
HIP 102155 |
18.14 |
| 2026-09-24 00:00 |
20:42:13.70 |
+42:00:03.7 |
HIP 102155 |
17.35 |
| 2026-09-24 12:00 |
20:42:11.37 |
+41:59:20.0 |
HIP 102155 |
16.55 |
| 2026-09-25 00:00 |
20:42:09.06 |
+41:58:36.2 |
HIP 102155 |
15.77 |
| 2026-09-25 12:00 |
20:42:06.80 |
+41:57:52.1 |
HIP 102155 |
14.98 |
| 2026-09-26 00:00 |
20:42:04.57 |
+41:57:07.9 |
HIP 102155 |
14.20 |
| 2026-09-26 12:00 |
20:42:02.37 |
+41:56:23.5 |
HIP 102155 |
13.42 |
| 2026-09-27 00:00 |
20:42:00.21 |
+41:55:38.9 |
HIP 102155 |
12.65 |
| 2026-09-27 12:00 |
20:41:58.09 |
+41:54:54.1 |
HIP 102155 |
11.89 |
| 2026-09-28 00:00 |
20:41:56.00 |
+41:54:09.1 |
HIP 102155 |
11.14 |
| 2026-09-28 12:00 |
20:41:53.95 |
+41:53:24.0 |
HIP 102155 |
10.40 |
| 2026-09-29 00:00 |
20:41:51.93 |
+41:52:38.7 |
HIP 102155 |
9.67 |
| 2026-09-29 12:00 |
20:41:49.95 |
+41:51:53.3 |
HIP 102155 |
8.96 |
| 2026-09-30 00:00 |
20:41:48.01 |
+41:51:07.7 |
HIP 102155 |
8.27 |
| 2026-09-30 12:00 |
20:41:46.11 |
+41:50:21.9 |
HIP 102155 |
7.60 |
| 2026-10-01 00:00 |
20:41:44.24 |
+41:49:36.0 |
HIP 102155 |
6.97 |
| 2026-10-01 12:00 |
20:41:42.41 |
+41:48:49.9 |
HIP 102155 |
6.38 |
| 2026-10-02 00:00 |
20:41:40.62 |
+41:48:03.7 |
HIP 102155 |
5.85 |
| 2026-10-02 12:00 |
20:41:38.86 |
+41:47:17.3 |
HIP 102155 |
5.40 |
| 2026-10-03 00:00 |
20:41:37.14 |
+41:46:30.8 |
HIP 102155 |
5.03 |
| 2026-10-03 12:00 |
20:41:35.47 |
+41:45:44.2 |
HIP 102155 |
4.78 |
| 2026-10-04 00:00 |
20:41:33.82 |
+41:44:57.4 |
HIP 102155 |
4.66 |
| 2026-10-04 12:00 |
20:41:32.22 |
+41:44:10.5 |
HIP 102155 |
4.68 |
| 2026-10-05 00:00 |
20:41:30.66 |
+41:43:23.5 |
HIP 102155 |
4.84 |
| 2026-10-05 12:00 |
20:41:29.13 |
+41:42:36.3 |
HIP 102155 |
5.12 |
| 2026-10-06 00:00 |
20:41:27.65 |
+41:41:49.1 |
HIP 102155 |
5.52 |
| 2026-10-06 12:00 |
20:41:26.20 |
+41:41:01.7 |
HIP 102155 |
5.99 |
| 2026-10-07 00:00 |
20:41:24.79 |
+41:40:14.2 |
HIP 102155 |
6.54 |
| 2026-10-07 12:00 |
20:41:23.42 |
+41:39:26.6 |
HIP 102155 |
7.13 |
| 2026-10-08 00:00 |
20:41:22.09 |
+41:38:38.9 |
HIP 102155 |
7.77 |
| 2026-10-08 12:00 |
20:41:20.80 |
+41:37:51.1 |
HIP 102155 |
8.43 |
| 2026-10-09 00:00 |
20:41:19.55 |
+41:37:03.2 |
HIP 102155 |
9.12 |
| 2026-10-09 12:00 |
20:41:18.34 |
+41:36:15.2 |
HIP 102155 |
9.82 |
| 2026-10-10 00:00 |
20:41:17.17 |
+41:35:27.2 |
HIP 102155 |
10.54 |
| 2026-10-10 12:00 |
20:41:16.04 |
+41:34:39.0 |
HIP 102155 |
11.27 |
| 2026-10-11 00:00 |
20:41:14.95 |
+41:33:50.8 |
HIP 102155 |
12.01 |