| Parameter |
Value |
| Designation |
C/2009 K5 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2010-04-30T00:35:23.349120Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:31Z |
| Obs used |
2488 |
| NEO |
- |
| M1 |
11.900 |
| K1 |
5.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2010-07-13.0000000 |
| e |
1.00083854 |
| q (au) |
1.422401 |
| a (au) |
-1696.276803 |
| i (deg) |
103.879390 |
| Ω (om, deg) |
257.856328 |
| ω (w, deg) |
66.174175 |
| M (ma, deg) |
0.001044 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.374 + 4.416\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.374 |
| n |
4.416 |
| gf |
0.999 |
| gb |
-0.589 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2009-05-27 |
2010-04-29 |
+0.0122 |
-1.630 |
| 2010-04-30 |
2010-09-19 |
+0.7909 |
-1.983 |
| 2010-09-19 |
2010-10-19 |
+22.6695 |
-9.980 |
| 2010-10-19 |
2011-11-26 |
-2.0385 |
+1.098 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-06-01 00:00 |
04:41:51.14 |
-18:18:07.8 |
HIP 21925 |
31.98 |
| 2026-06-01 12:00 |
04:41:54.57 |
-18:18:04.3 |
HIP 21925 |
31.57 |
| 2026-06-02 00:00 |
04:41:58.00 |
-18:18:01.0 |
HIP 21925 |
31.17 |
| 2026-06-02 12:00 |
04:42:01.44 |
-18:17:58.0 |
HIP 21925 |
30.80 |
| 2026-06-03 00:00 |
04:42:04.87 |
-18:17:55.3 |
HIP 21925 |
30.45 |
| 2026-06-03 12:00 |
04:42:08.31 |
-18:17:52.8 |
HIP 21925 |
30.12 |
| 2026-06-04 00:00 |
04:42:11.74 |
-18:17:50.7 |
HIP 21925 |
29.81 |
| 2026-06-04 12:00 |
04:42:15.17 |
-18:17:48.8 |
HIP 21925 |
29.53 |
| 2026-06-05 00:00 |
04:42:18.60 |
-18:17:47.1 |
HIP 21925 |
29.27 |
| 2026-06-05 12:00 |
04:42:22.03 |
-18:17:45.8 |
HIP 21925 |
29.04 |
| 2026-06-06 00:00 |
04:42:25.46 |
-18:17:44.7 |
HIP 21925 |
28.83 |
| 2026-06-06 12:00 |
04:42:28.89 |
-18:17:43.8 |
HIP 21925 |
28.65 |
| 2026-06-07 00:00 |
04:42:32.32 |
-18:17:43.3 |
HIP 21925 |
28.50 |
| 2026-06-07 12:00 |
04:42:35.74 |
-18:17:43.0 |
HIP 21925 |
28.37 |
| 2026-06-08 00:00 |
04:42:39.16 |
-18:17:43.0 |
HIP 21925 |
28.27 |
| 2026-06-08 12:00 |
04:42:42.58 |
-18:17:43.2 |
HIP 21925 |
28.20 |
| 2026-06-09 00:00 |
04:42:46.00 |
-18:17:43.8 |
HIP 21925 |
28.16 |
| 2026-06-09 12:00 |
04:42:49.41 |
-18:17:44.6 |
HIP 21925 |
28.14 |
| 2026-06-10 00:00 |
04:42:52.82 |
-18:17:45.6 |
HIP 21925 |
28.15 |
| 2026-06-10 12:00 |
04:42:56.23 |
-18:17:47.0 |
HIP 22028 |
27.97 |
| 2026-06-11 00:00 |
04:42:59.63 |
-18:17:48.6 |
HIP 22028 |
27.47 |
| 2026-06-11 12:00 |
04:43:03.03 |
-18:17:50.5 |
HIP 22028 |
26.97 |
| 2026-06-12 00:00 |
04:43:06.43 |
-18:17:52.7 |
HIP 22028 |
26.49 |
| 2026-06-12 12:00 |
04:43:09.82 |
-18:17:55.1 |
HIP 22028 |
26.02 |
| 2026-06-13 00:00 |
04:43:13.21 |
-18:17:57.9 |
HIP 22028 |
25.57 |
| 2026-06-13 12:00 |
04:43:16.59 |
-18:18:00.9 |
HIP 22028 |
25.13 |
| 2026-06-14 00:00 |
04:43:19.97 |
-18:18:04.1 |
HIP 22028 |
24.70 |
| 2026-06-14 12:00 |
04:43:23.34 |
-18:18:07.7 |
HIP 22028 |
24.29 |
| 2026-06-15 00:00 |
04:43:26.71 |
-18:18:11.5 |
HIP 22028 |
23.89 |
| 2026-06-15 12:00 |
04:43:30.07 |
-18:18:15.6 |
HIP 22028 |
23.52 |
| 2026-06-16 00:00 |
04:43:33.43 |
-18:18:20.0 |
HIP 22028 |
23.16 |
| 2026-06-16 12:00 |
04:43:36.78 |
-18:18:24.6 |
HIP 22028 |
22.81 |
| 2026-06-17 00:00 |
04:43:40.12 |
-18:18:29.5 |
HIP 22028 |
22.49 |
| 2026-06-17 12:00 |
04:43:43.46 |
-18:18:34.7 |
HIP 22028 |
22.19 |
| 2026-06-18 00:00 |
04:43:46.78 |
-18:18:40.2 |
HIP 22028 |
21.91 |
| 2026-06-18 12:00 |
04:43:50.11 |
-18:18:45.9 |
HIP 22028 |
21.65 |
| 2026-06-19 00:00 |
04:43:53.42 |
-18:18:51.9 |
HIP 22028 |
21.41 |
| 2026-06-19 12:00 |
04:43:56.73 |
-18:18:58.2 |
HIP 22028 |
21.19 |
| 2026-06-20 00:00 |
04:44:00.03 |
-18:19:04.7 |
HIP 22028 |
21.00 |
| 2026-06-20 12:00 |
04:44:03.32 |
-18:19:11.6 |
HIP 22028 |
20.83 |
| 2026-06-21 00:00 |
04:44:06.60 |
-18:19:18.7 |
HIP 22028 |
20.68 |
| 2026-06-21 12:00 |
04:44:09.88 |
-18:19:26.0 |
HIP 22028 |
20.56 |
| 2026-06-22 00:00 |
04:44:13.14 |
-18:19:33.7 |
HIP 22028 |
20.47 |