| Parameter |
Value |
| Designation |
C/2005 L3 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2008-01-16T08:18:53.772480Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:51Z |
| Obs used |
5219 |
| NEO |
- |
| M1 |
8.400 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2008-09-20.0000000 |
| e |
0.99958663 |
| q (au) |
5.593628 |
| a (au) |
13531.707446 |
| i (deg) |
139.449247 |
| Ω (om, deg) |
288.739815 |
| ω (w, deg) |
47.133870 |
| M (ma, deg) |
0.000155 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.595 + 2.591\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.595 |
| n |
2.591 |
| gf |
1.000 |
| gb |
-0.502 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2004-07-16 |
2008-01-12 |
+3.1774 |
-2.093 |
| 2008-01-25 |
2010-02-06 |
-2.6501 |
+1.894 |
| 2010-02-06 |
2014-01-09 |
-0.3685 |
+0.184 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
07:24:11.10 |
+22:09:52.2 |
HIP 35807 |
19.01 |
| 2026-07-29 12:00 |
07:24:14.15 |
+22:09:43.0 |
HIP 35807 |
19.48 |
| 2026-07-30 00:00 |
07:24:17.20 |
+22:09:33.8 |
HIP 35807 |
19.97 |
| 2026-07-30 12:00 |
07:24:20.23 |
+22:09:24.5 |
HIP 35807 |
20.47 |
| 2026-07-31 00:00 |
07:24:23.25 |
+22:09:15.3 |
HIP 35807 |
20.98 |
| 2026-07-31 12:00 |
07:24:26.27 |
+22:09:06.2 |
HIP 35807 |
21.50 |
| 2026-08-01 00:00 |
07:24:29.27 |
+22:08:57.0 |
HIP 35807 |
22.03 |
| 2026-08-01 12:00 |
07:24:32.27 |
+22:08:47.8 |
HIP 35807 |
22.56 |
| 2026-08-02 00:00 |
07:24:35.26 |
+22:08:38.7 |
HIP 35807 |
23.11 |
| 2026-08-02 12:00 |
07:24:38.23 |
+22:08:29.6 |
HIP 35807 |
23.66 |
| 2026-08-03 00:00 |
07:24:41.20 |
+22:08:20.5 |
HIP 35807 |
24.22 |
| 2026-08-03 12:00 |
07:24:44.16 |
+22:08:11.4 |
HIP 36086 |
24.10 |
| 2026-08-04 00:00 |
07:24:47.10 |
+22:08:02.3 |
HIP 36086 |
23.47 |
| 2026-08-04 12:00 |
07:24:50.04 |
+22:07:53.3 |
HIP 36086 |
22.85 |
| 2026-08-05 00:00 |
07:24:52.96 |
+22:07:44.3 |
HIP 36086 |
22.23 |
| 2026-08-05 12:00 |
07:24:55.88 |
+22:07:35.3 |
HIP 36086 |
21.62 |
| 2026-08-06 00:00 |
07:24:58.78 |
+22:07:26.3 |
HIP 36086 |
21.01 |
| 2026-08-06 12:00 |
07:25:01.67 |
+22:07:17.3 |
HIP 36086 |
20.42 |
| 2026-08-07 00:00 |
07:25:04.55 |
+22:07:08.4 |
HIP 36086 |
19.83 |
| 2026-08-07 12:00 |
07:25:07.42 |
+22:06:59.4 |
HIP 36086 |
19.25 |
| 2026-08-08 00:00 |
07:25:10.27 |
+22:06:50.5 |
HIP 36086 |
18.67 |
| 2026-08-08 12:00 |
07:25:13.11 |
+22:06:41.6 |
HIP 36086 |
18.11 |
| 2026-08-09 00:00 |
07:25:15.94 |
+22:06:32.8 |
HIP 36086 |
17.56 |
| 2026-08-09 12:00 |
07:25:18.76 |
+22:06:23.9 |
HIP 36086 |
17.02 |
| 2026-08-10 00:00 |
07:25:21.56 |
+22:06:15.1 |
HIP 36086 |
16.49 |
| 2026-08-10 12:00 |
07:25:24.35 |
+22:06:06.3 |
HIP 36086 |
15.97 |
| 2026-08-11 00:00 |
07:25:27.13 |
+22:05:57.6 |
HIP 36086 |
15.47 |
| 2026-08-11 12:00 |
07:25:29.89 |
+22:05:48.8 |
HIP 36086 |
14.98 |
| 2026-08-12 00:00 |
07:25:32.64 |
+22:05:40.1 |
HIP 36086 |
14.51 |
| 2026-08-12 12:00 |
07:25:35.37 |
+22:05:31.4 |
HIP 36086 |
14.05 |
| 2026-08-13 00:00 |
07:25:38.09 |
+22:05:22.8 |
HIP 36086 |
13.61 |
| 2026-08-13 12:00 |
07:25:40.80 |
+22:05:14.2 |
HIP 36086 |
13.19 |
| 2026-08-14 00:00 |
07:25:43.49 |
+22:05:05.6 |
HIP 36086 |
12.79 |
| 2026-08-14 12:00 |
07:25:46.16 |
+22:04:57.0 |
HIP 36086 |
12.41 |
| 2026-08-15 00:00 |
07:25:48.82 |
+22:04:48.4 |
HIP 36086 |
12.06 |
| 2026-08-15 12:00 |
07:25:51.46 |
+22:04:39.9 |
HIP 36086 |
11.72 |
| 2026-08-16 00:00 |
07:25:54.09 |
+22:04:31.4 |
HIP 36086 |
11.42 |
| 2026-08-16 12:00 |
07:25:56.70 |
+22:04:23.0 |
HIP 36086 |
11.15 |
| 2026-08-17 00:00 |
07:25:59.30 |
+22:04:14.5 |
HIP 36086 |
10.90 |
| 2026-08-17 12:00 |
07:26:01.88 |
+22:04:06.1 |
HIP 36086 |
10.69 |
| 2026-08-18 00:00 |
07:26:04.44 |
+22:03:57.8 |
HIP 36086 |
10.50 |
| 2026-08-18 12:00 |
07:26:06.99 |
+22:03:49.5 |
HIP 36086 |
10.35 |
| 2026-08-19 00:00 |
07:26:09.51 |
+22:03:41.2 |
HIP 36086 |
10.24 |