| 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) |
| 2026-07-29 00:00 |
20:49:19.09 |
+42:49:33.1 |
HIP 102746 |
8.03 |
| 2026-07-29 12:00 |
20:49:14.72 |
+42:49:28.8 |
HIP 102746 |
7.93 |
| 2026-07-30 00:00 |
20:49:10.35 |
+42:49:24.1 |
HIP 102746 |
7.91 |
| 2026-07-30 12:00 |
20:49:05.97 |
+42:49:19.0 |
HIP 102746 |
7.98 |
| 2026-07-31 00:00 |
20:49:01.60 |
+42:49:13.5 |
HIP 102746 |
8.14 |
| 2026-07-31 12:00 |
20:48:57.22 |
+42:49:07.5 |
HIP 102746 |
8.38 |
| 2026-08-01 00:00 |
20:48:52.84 |
+42:49:01.1 |
HIP 102746 |
8.70 |
| 2026-08-01 12:00 |
20:48:48.46 |
+42:48:54.3 |
HIP 102746 |
9.08 |
| 2026-08-02 00:00 |
20:48:44.08 |
+42:48:47.1 |
HIP 102746 |
9.52 |
| 2026-08-02 12:00 |
20:48:39.70 |
+42:48:39.4 |
HIP 102746 |
10.02 |
| 2026-08-03 00:00 |
20:48:35.32 |
+42:48:31.3 |
HIP 102746 |
10.56 |
| 2026-08-03 12:00 |
20:48:30.94 |
+42:48:22.8 |
HIP 102746 |
11.14 |
| 2026-08-04 00:00 |
20:48:26.57 |
+42:48:13.8 |
HIP 102746 |
11.75 |
| 2026-08-04 12:00 |
20:48:22.19 |
+42:48:04.5 |
HIP 102746 |
12.40 |
| 2026-08-05 00:00 |
20:48:17.81 |
+42:47:54.7 |
HIP 102746 |
13.06 |
| 2026-08-05 12:00 |
20:48:13.44 |
+42:47:44.5 |
HIP 102746 |
13.75 |
| 2026-08-06 00:00 |
20:48:09.07 |
+42:47:33.8 |
HIP 102746 |
14.46 |
| 2026-08-06 12:00 |
20:48:04.70 |
+42:47:22.8 |
HIP 102746 |
15.18 |
| 2026-08-07 00:00 |
20:48:00.34 |
+42:47:11.3 |
HIP 102746 |
15.91 |
| 2026-08-07 12:00 |
20:47:55.98 |
+42:46:59.4 |
HIP 102746 |
16.66 |
| 2026-08-08 00:00 |
20:47:51.62 |
+42:46:47.0 |
HIP 102746 |
17.42 |
| 2026-08-08 12:00 |
20:47:47.27 |
+42:46:34.3 |
HIP 102746 |
18.18 |
| 2026-08-09 00:00 |
20:47:42.92 |
+42:46:21.1 |
HIP 102746 |
18.96 |
| 2026-08-09 12:00 |
20:47:38.58 |
+42:46:07.5 |
HIP 102746 |
19.74 |
| 2026-08-10 00:00 |
20:47:34.24 |
+42:45:53.5 |
HIP 102746 |
20.53 |
| 2026-08-10 12:00 |
20:47:29.91 |
+42:45:39.0 |
HIP 102746 |
21.33 |
| 2026-08-11 00:00 |
20:47:25.59 |
+42:45:24.2 |
HIP 102570 |
21.01 |
| 2026-08-11 12:00 |
20:47:21.27 |
+42:45:08.9 |
HIP 102570 |
20.66 |
| 2026-08-12 00:00 |
20:47:16.97 |
+42:44:53.2 |
HIP 102570 |
20.34 |
| 2026-08-12 12:00 |
20:47:12.66 |
+42:44:37.2 |
HIP 102570 |
20.04 |
| 2026-08-13 00:00 |
20:47:08.37 |
+42:44:20.6 |
HIP 102570 |
19.76 |
| 2026-08-13 12:00 |
20:47:04.09 |
+42:44:03.7 |
HIP 102570 |
19.50 |
| 2026-08-14 00:00 |
20:46:59.81 |
+42:43:46.4 |
HIP 102570 |
19.27 |
| 2026-08-14 12:00 |
20:46:55.54 |
+42:43:28.7 |
HIP 102570 |
19.07 |
| 2026-08-15 00:00 |
20:46:51.29 |
+42:43:10.5 |
HIP 102570 |
18.90 |
| 2026-08-15 12:00 |
20:46:47.04 |
+42:42:52.0 |
HIP 102570 |
18.75 |
| 2026-08-16 00:00 |
20:46:42.81 |
+42:42:33.0 |
HIP 102570 |
18.64 |
| 2026-08-16 12:00 |
20:46:38.58 |
+42:42:13.7 |
HIP 102570 |
18.56 |
| 2026-08-17 00:00 |
20:46:34.37 |
+42:41:53.9 |
HIP 102570 |
18.50 |
| 2026-08-17 12:00 |
20:46:30.17 |
+42:41:33.7 |
HIP 102570 |
18.48 |
| 2026-08-18 00:00 |
20:46:25.98 |
+42:41:13.2 |
HIP 102570 |
18.49 |
| 2026-08-18 12:00 |
20:46:21.80 |
+42:40:52.2 |
HIP 102570 |
18.54 |
| 2026-08-19 00:00 |
20:46:17.64 |
+42:40:30.9 |
HIP 102570 |
18.61 |