| 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) |
| 2026-03-26 00:00 |
04:33:39.38 |
+48:55:52.9 |
HIP 21166 |
41.23 |
| 2026-03-26 12:00 |
04:33:40.96 |
+48:55:36.6 |
HIP 21166 |
41.07 |
| 2026-03-27 00:00 |
04:33:42.58 |
+48:55:20.4 |
HIP 21166 |
40.90 |
| 2026-03-27 12:00 |
04:33:44.23 |
+48:55:04.3 |
HIP 21166 |
40.75 |
| 2026-03-28 00:00 |
04:33:45.91 |
+48:54:48.4 |
HIP 21166 |
40.60 |
| 2026-03-28 12:00 |
04:33:47.62 |
+48:54:32.6 |
HIP 21166 |
40.46 |
| 2026-03-29 00:00 |
04:33:49.37 |
+48:54:16.9 |
HIP 21166 |
40.33 |
| 2026-03-29 12:00 |
04:33:51.15 |
+48:54:01.4 |
HIP 21166 |
40.20 |
| 2026-03-30 00:00 |
04:33:52.97 |
+48:53:46.0 |
HIP 21166 |
40.08 |
| 2026-03-30 12:00 |
04:33:54.81 |
+48:53:30.7 |
HIP 21166 |
39.97 |
| 2026-03-31 00:00 |
04:33:56.69 |
+48:53:15.6 |
HIP 21166 |
39.87 |
| 2026-03-31 12:00 |
04:33:58.60 |
+48:53:00.6 |
HIP 21166 |
39.77 |
| 2026-04-01 00:00 |
04:34:00.54 |
+48:52:45.7 |
HIP 21166 |
39.69 |
| 2026-04-01 12:00 |
04:34:02.52 |
+48:52:31.0 |
HIP 21166 |
39.61 |
| 2026-04-02 00:00 |
04:34:04.52 |
+48:52:16.4 |
HIP 21166 |
39.54 |
| 2026-04-02 12:00 |
04:34:06.56 |
+48:52:01.9 |
HIP 21166 |
39.48 |
| 2026-04-03 00:00 |
04:34:08.63 |
+48:51:47.6 |
HIP 21166 |
39.42 |
| 2026-04-03 12:00 |
04:34:10.73 |
+48:51:33.4 |
HIP 21166 |
39.38 |
| 2026-04-04 00:00 |
04:34:12.86 |
+48:51:19.4 |
HIP 21166 |
39.34 |
| 2026-04-04 12:00 |
04:34:15.02 |
+48:51:05.5 |
HIP 21166 |
39.32 |
| 2026-04-05 00:00 |
04:34:17.21 |
+48:50:51.7 |
HIP 21507 |
39.00 |
| 2026-04-05 12:00 |
04:34:19.43 |
+48:50:38.1 |
HIP 21507 |
38.58 |
| 2026-04-06 00:00 |
04:34:21.68 |
+48:50:24.6 |
HIP 21507 |
38.16 |
| 2026-04-06 12:00 |
04:34:23.96 |
+48:50:11.3 |
HIP 21507 |
37.73 |
| 2026-04-07 00:00 |
04:34:26.27 |
+48:49:58.1 |
HIP 21507 |
37.31 |
| 2026-04-07 12:00 |
04:34:28.61 |
+48:49:45.1 |
HIP 21507 |
36.88 |
| 2026-04-08 00:00 |
04:34:30.97 |
+48:49:32.2 |
HIP 21507 |
36.45 |
| 2026-04-08 12:00 |
04:34:33.37 |
+48:49:19.4 |
HIP 21507 |
36.02 |
| 2026-04-09 00:00 |
04:34:35.80 |
+48:49:06.8 |
HIP 21507 |
35.59 |
| 2026-04-09 12:00 |
04:34:38.25 |
+48:48:54.3 |
HIP 21507 |
35.15 |
| 2026-04-10 00:00 |
04:34:40.74 |
+48:48:42.0 |
HIP 21507 |
34.72 |
| 2026-04-10 12:00 |
04:34:43.25 |
+48:48:29.8 |
HIP 21507 |
34.29 |
| 2026-04-11 00:00 |
04:34:45.79 |
+48:48:17.8 |
HIP 21507 |
33.85 |
| 2026-04-11 12:00 |
04:34:48.35 |
+48:48:06.0 |
HIP 21507 |
33.41 |
| 2026-04-12 00:00 |
04:34:50.95 |
+48:47:54.2 |
HIP 21507 |
32.98 |
| 2026-04-12 12:00 |
04:34:53.57 |
+48:47:42.7 |
HIP 21507 |
32.54 |
| 2026-04-13 00:00 |
04:34:56.22 |
+48:47:31.2 |
HIP 21507 |
32.10 |
| 2026-04-13 12:00 |
04:34:58.89 |
+48:47:20.0 |
HIP 21507 |
31.66 |
| 2026-04-14 00:00 |
04:35:01.60 |
+48:47:08.9 |
HIP 21507 |
31.23 |
| 2026-04-14 12:00 |
04:35:04.33 |
+48:46:57.9 |
HIP 21507 |
30.79 |
| 2026-04-15 00:00 |
04:35:07.08 |
+48:46:47.1 |
HIP 21507 |
30.35 |
| 2026-04-15 12:00 |
04:35:09.86 |
+48:46:36.5 |
HIP 21507 |
29.92 |
| 2026-04-16 00:00 |
04:35:12.67 |
+48:46:26.0 |
HIP 21507 |
29.49 |