| Parameter |
Value |
| Designation |
C/2011 L3 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2011-08-10T12:00:37.532160Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:51Z |
| Obs used |
798 |
| NEO |
- |
| M1 |
14.700 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2011-08-05.0000000 |
| e |
1.00010168 |
| q (au) |
1.923846 |
| a (au) |
-18921.284723 |
| i (deg) |
87.114423 |
| Ω (om, deg) |
307.755201 |
| ω (w, deg) |
27.727029 |
| M (ma, deg) |
-0.000002 |
Magnitude
Scatter + Global Linear
$$
M_a = (15.294 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
15.294 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.528 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
08:40:35.97 |
+18:46:18.3 |
HIP 42487 |
18.17 |
| 2026-07-29 12:00 |
08:40:39.50 |
+18:46:01.6 |
HIP 42487 |
18.56 |
| 2026-07-30 00:00 |
08:40:43.02 |
+18:45:45.0 |
HIP 42487 |
18.99 |
| 2026-07-30 12:00 |
08:40:46.55 |
+18:45:28.3 |
HIP 42487 |
19.44 |
| 2026-07-31 00:00 |
08:40:50.08 |
+18:45:11.6 |
HIP 42487 |
19.93 |
| 2026-07-31 12:00 |
08:40:53.61 |
+18:44:55.0 |
HIP 42487 |
20.44 |
| 2026-08-01 00:00 |
08:40:57.13 |
+18:44:38.3 |
HIP 42705 |
20.85 |
| 2026-08-01 12:00 |
08:41:00.66 |
+18:44:21.7 |
HIP 42705 |
20.31 |
| 2026-08-02 00:00 |
08:41:04.18 |
+18:44:05.0 |
HIP 42705 |
19.80 |
| 2026-08-02 12:00 |
08:41:07.71 |
+18:43:48.4 |
HIP 42705 |
19.32 |
| 2026-08-03 00:00 |
08:41:11.23 |
+18:43:31.7 |
HIP 42705 |
18.87 |
| 2026-08-03 12:00 |
08:41:14.75 |
+18:43:15.1 |
HIP 42705 |
18.45 |
| 2026-08-04 00:00 |
08:41:18.27 |
+18:42:58.5 |
HIP 42705 |
18.06 |
| 2026-08-04 12:00 |
08:41:21.78 |
+18:42:41.8 |
HIP 42705 |
17.70 |
| 2026-08-05 00:00 |
08:41:25.30 |
+18:42:25.2 |
HIP 42705 |
17.39 |
| 2026-08-05 12:00 |
08:41:28.81 |
+18:42:08.6 |
HIP 42705 |
17.11 |
| 2026-08-06 00:00 |
08:41:32.32 |
+18:41:52.0 |
HIP 42705 |
16.87 |
| 2026-08-06 12:00 |
08:41:35.82 |
+18:41:35.4 |
HIP 42705 |
16.68 |
| 2026-08-07 00:00 |
08:41:39.33 |
+18:41:18.8 |
HIP 42705 |
16.53 |
| 2026-08-07 12:00 |
08:41:42.82 |
+18:41:02.3 |
HIP 42705 |
16.42 |
| 2026-08-08 00:00 |
08:41:46.32 |
+18:40:45.7 |
HIP 42705 |
16.37 |
| 2026-08-08 12:00 |
08:41:49.81 |
+18:40:29.2 |
HIP 42705 |
16.35 |
| 2026-08-09 00:00 |
08:41:53.30 |
+18:40:12.6 |
HIP 42705 |
16.39 |
| 2026-08-09 12:00 |
08:41:56.78 |
+18:39:56.1 |
HIP 42705 |
16.47 |
| 2026-08-10 00:00 |
08:42:00.26 |
+18:39:39.6 |
HIP 42705 |
16.59 |
| 2026-08-10 12:00 |
08:42:03.73 |
+18:39:23.1 |
HIP 42705 |
16.76 |
| 2026-08-11 00:00 |
08:42:07.20 |
+18:39:06.7 |
HIP 42705 |
16.97 |
| 2026-08-11 12:00 |
08:42:10.66 |
+18:38:50.2 |
HIP 42705 |
17.23 |
| 2026-08-12 00:00 |
08:42:14.12 |
+18:38:33.8 |
HIP 42705 |
17.52 |
| 2026-08-12 12:00 |
08:42:17.57 |
+18:38:17.4 |
HIP 42705 |
17.85 |
| 2026-08-13 00:00 |
08:42:21.01 |
+18:38:01.0 |
HIP 42705 |
18.21 |
| 2026-08-13 12:00 |
08:42:24.45 |
+18:37:44.7 |
HIP 42705 |
18.60 |
| 2026-08-14 00:00 |
08:42:27.88 |
+18:37:28.4 |
HIP 42705 |
19.02 |
| 2026-08-14 12:00 |
08:42:31.30 |
+18:37:12.0 |
HIP 42705 |
19.48 |
| 2026-08-15 00:00 |
08:42:34.72 |
+18:36:55.8 |
HIP 42705 |
19.95 |
| 2026-08-15 12:00 |
08:42:38.13 |
+18:36:39.5 |
HIP 42705 |
20.45 |
| 2026-08-16 00:00 |
08:42:41.53 |
+18:36:23.3 |
HIP 42705 |
20.98 |
| 2026-08-16 12:00 |
08:42:44.93 |
+18:36:07.1 |
HIP 42705 |
21.52 |
| 2026-08-17 00:00 |
08:42:48.31 |
+18:35:50.9 |
HIP 42705 |
22.08 |
| 2026-08-17 12:00 |
08:42:51.69 |
+18:35:34.8 |
HIP 42705 |
22.65 |
| 2026-08-18 00:00 |
08:42:55.06 |
+18:35:18.7 |
HIP 42705 |
23.24 |
| 2026-08-18 12:00 |
08:42:58.42 |
+18:35:02.6 |
HIP 42705 |
23.85 |
| 2026-08-19 00:00 |
08:43:01.77 |
+18:34:46.6 |
HIP 42705 |
24.47 |