| Parameter |
Value |
| Designation |
C/2005 L2 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2005-07-14T12:31:58.244160Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:30:50Z |
| Obs used |
54 |
| NEO |
- |
| M1 |
14.400 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2005-09-03.0000000 |
| e |
0.99997944 |
| q (au) |
3.193792 |
| a (au) |
155353.269479 |
| i (deg) |
152.764081 |
| Ω (om, deg) |
155.872566 |
| ω (w, deg) |
294.238895 |
| M (ma, deg) |
0.000001 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.145 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.145 |
| n |
2.000 |
| gf |
0.984 |
| gb |
-0.846 |
| k |
0.982 |
| 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) |
| 2026-05-12 00:00 |
04:38:07.46 |
+48:41:01.0 |
HIP 21659 |
11.30 |
| 2026-05-12 12:00 |
04:38:11.25 |
+48:40:59.1 |
HIP 21659 |
10.79 |
| 2026-05-13 00:00 |
04:38:15.06 |
+48:40:57.3 |
HIP 21659 |
10.29 |
| 2026-05-13 12:00 |
04:38:18.87 |
+48:40:55.7 |
HIP 21659 |
9.81 |
| 2026-05-14 00:00 |
04:38:22.70 |
+48:40:54.3 |
HIP 21659 |
9.35 |
| 2026-05-14 12:00 |
04:38:26.54 |
+48:40:53.0 |
HIP 21659 |
8.92 |
| 2026-05-15 00:00 |
04:38:30.39 |
+48:40:51.9 |
HIP 21659 |
8.50 |
| 2026-05-15 12:00 |
04:38:34.24 |
+48:40:51.0 |
HIP 21659 |
8.12 |
| 2026-05-16 00:00 |
04:38:38.11 |
+48:40:50.2 |
HIP 21659 |
7.78 |
| 2026-05-16 12:00 |
04:38:41.99 |
+48:40:49.6 |
HIP 21659 |
7.47 |
| 2026-05-17 00:00 |
04:38:45.88 |
+48:40:49.1 |
HIP 21659 |
7.21 |
| 2026-05-17 12:00 |
04:38:49.78 |
+48:40:48.8 |
HIP 21659 |
7.00 |
| 2026-05-18 00:00 |
04:38:53.68 |
+48:40:48.7 |
HIP 21659 |
6.85 |
| 2026-05-18 12:00 |
04:38:57.60 |
+48:40:48.7 |
HIP 21659 |
6.76 |
| 2026-05-19 00:00 |
04:39:01.52 |
+48:40:48.9 |
HIP 21659 |
6.74 |
| 2026-05-19 12:00 |
04:39:05.45 |
+48:40:49.3 |
HIP 21659 |
6.78 |
| 2026-05-20 00:00 |
04:39:09.38 |
+48:40:49.8 |
HIP 21659 |
6.88 |
| 2026-05-20 12:00 |
04:39:13.33 |
+48:40:50.5 |
HIP 21659 |
7.05 |
| 2026-05-21 00:00 |
04:39:17.28 |
+48:40:51.4 |
HIP 21659 |
7.27 |
| 2026-05-21 12:00 |
04:39:21.24 |
+48:40:52.4 |
HIP 21659 |
7.54 |
| 2026-05-22 00:00 |
04:39:25.20 |
+48:40:53.6 |
HIP 21659 |
7.87 |
| 2026-05-22 12:00 |
04:39:29.17 |
+48:40:54.9 |
HIP 21659 |
8.23 |
| 2026-05-23 00:00 |
04:39:33.15 |
+48:40:56.4 |
HIP 21659 |
8.64 |
| 2026-05-23 12:00 |
04:39:37.13 |
+48:40:58.1 |
HIP 21659 |
9.07 |
| 2026-05-24 00:00 |
04:39:41.12 |
+48:40:59.9 |
HIP 21659 |
9.54 |
| 2026-05-24 12:00 |
04:39:45.11 |
+48:41:01.9 |
HIP 21659 |
10.03 |
| 2026-05-25 00:00 |
04:39:49.10 |
+48:41:04.0 |
HIP 21659 |
10.53 |
| 2026-05-25 12:00 |
04:39:53.10 |
+48:41:06.3 |
HIP 21659 |
11.06 |
| 2026-05-26 00:00 |
04:39:57.11 |
+48:41:08.8 |
HIP 21800 |
10.52 |
| 2026-05-26 12:00 |
04:40:01.12 |
+48:41:11.4 |
HIP 21800 |
9.87 |
| 2026-05-27 00:00 |
04:40:05.13 |
+48:41:14.1 |
HIP 21800 |
9.22 |
| 2026-05-27 12:00 |
04:40:09.14 |
+48:41:17.1 |
HIP 21800 |
8.57 |
| 2026-05-28 00:00 |
04:40:13.16 |
+48:41:20.2 |
HIP 21800 |
7.92 |
| 2026-05-28 12:00 |
04:40:17.18 |
+48:41:23.4 |
HIP 21800 |
7.27 |
| 2026-05-29 00:00 |
04:40:21.21 |
+48:41:26.8 |
HIP 21800 |
6.63 |
| 2026-05-29 12:00 |
04:40:25.23 |
+48:41:30.4 |
HIP 21800 |
6.00 |
| 2026-05-30 00:00 |
04:40:29.26 |
+48:41:34.1 |
HIP 21800 |
5.37 |
| 2026-05-30 12:00 |
04:40:33.29 |
+48:41:38.0 |
HIP 21800 |
4.75 |
| 2026-05-31 00:00 |
04:40:37.32 |
+48:41:42.0 |
HIP 21800 |
4.15 |
| 2026-05-31 12:00 |
04:40:41.35 |
+48:41:46.2 |
HIP 21800 |
3.58 |
| 2026-06-01 00:00 |
04:40:45.38 |
+48:41:50.5 |
HIP 21800 |
3.05 |
| 2026-06-01 12:00 |
04:40:49.42 |
+48:41:55.0 |
HIP 21800 |
2.59 |
| 2026-06-02 00:00 |
04:40:53.45 |
+48:41:59.6 |
HIP 21800 |
2.23 |