| Parameter |
Value |
| Designation |
C/2011 L1 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2010-12-18T07:14:56.696640Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:51Z |
| Obs used |
140 |
| NEO |
- |
| M1 |
10.400 |
| K1 |
12.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2011-06-22.0000000 |
| e |
0.79679852 |
| q (au) |
2.242374 |
| a (au) |
11.035223 |
| i (deg) |
65.512678 |
| Ω (om, deg) |
252.363846 |
| ω (w, deg) |
294.470660 |
| M (ma, deg) |
4.992746 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.123 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.123 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.781 |
| k |
0.999 |
| 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 |
| 2011-06-02 |
2012-07-23 |
-10.7811 |
+4.882 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
23:02:38.93 |
+59:22:28.2 |
HIP 113790 |
13.83 |
| 2026-05-12 12:00 |
23:02:44.44 |
+59:23:48.4 |
HIP 113790 |
12.53 |
| 2026-05-13 00:00 |
23:02:49.86 |
+59:25:08.7 |
HIP 113790 |
11.27 |
| 2026-05-13 12:00 |
23:02:55.22 |
+59:26:29.2 |
HIP 113790 |
10.07 |
| 2026-05-14 00:00 |
23:03:00.49 |
+59:27:49.9 |
HIP 113790 |
8.97 |
| 2026-05-14 12:00 |
23:03:05.69 |
+59:29:10.7 |
HIP 113790 |
7.98 |
| 2026-05-15 00:00 |
23:03:10.82 |
+59:30:31.6 |
HIP 113790 |
7.16 |
| 2026-05-15 12:00 |
23:03:15.86 |
+59:31:52.6 |
HIP 113790 |
6.58 |
| 2026-05-16 00:00 |
23:03:20.83 |
+59:33:13.8 |
HIP 113790 |
6.30 |
| 2026-05-16 12:00 |
23:03:25.72 |
+59:34:35.1 |
HIP 113790 |
6.35 |
| 2026-05-17 00:00 |
23:03:30.53 |
+59:35:56.6 |
HIP 113790 |
6.73 |
| 2026-05-17 12:00 |
23:03:35.26 |
+59:37:18.1 |
HIP 113790 |
7.39 |
| 2026-05-18 00:00 |
23:03:39.91 |
+59:38:39.8 |
HIP 113918 |
6.27 |
| 2026-05-18 12:00 |
23:03:44.48 |
+59:40:01.5 |
HIP 113918 |
4.86 |
| 2026-05-19 00:00 |
23:03:48.97 |
+59:41:23.4 |
HIP 113918 |
3.51 |
| 2026-05-19 12:00 |
23:03:53.38 |
+59:42:45.3 |
HIP 113918 |
2.32 |
| 2026-05-20 00:00 |
23:03:57.70 |
+59:44:07.3 |
HIP 113918 |
1.69 |
| 2026-05-20 12:00 |
23:04:01.95 |
+59:45:29.5 |
HIP 113918 |
2.17 |
| 2026-05-21 00:00 |
23:04:06.12 |
+59:46:51.7 |
HIP 113918 |
3.30 |
| 2026-05-21 12:00 |
23:04:10.20 |
+59:48:13.9 |
HIP 113918 |
4.62 |
| 2026-05-22 00:00 |
23:04:14.20 |
+59:49:36.2 |
HIP 113918 |
6.01 |
| 2026-05-22 12:00 |
23:04:18.12 |
+59:50:58.6 |
HIP 113918 |
7.43 |
| 2026-05-23 00:00 |
23:04:21.95 |
+59:52:21.1 |
HIP 113918 |
8.86 |
| 2026-05-23 12:00 |
23:04:25.70 |
+59:53:43.6 |
HIP 113918 |
10.30 |
| 2026-05-24 00:00 |
23:04:29.37 |
+59:55:06.1 |
HIP 113918 |
11.74 |
| 2026-05-24 12:00 |
23:04:32.96 |
+59:56:28.7 |
HIP 113918 |
13.18 |
| 2026-05-25 00:00 |
23:04:36.46 |
+59:57:51.3 |
HIP 113918 |
14.62 |
| 2026-05-25 12:00 |
23:04:39.87 |
+59:59:14.0 |
HIP 113918 |
16.05 |
| 2026-05-26 00:00 |
23:04:43.21 |
+60:00:36.6 |
HIP 113918 |
17.49 |
| 2026-05-26 12:00 |
23:04:46.45 |
+60:01:59.3 |
HIP 113918 |
18.93 |
| 2026-05-27 00:00 |
23:04:49.61 |
+60:03:22.0 |
HIP 113918 |
20.36 |
| 2026-05-27 12:00 |
23:04:52.69 |
+60:04:44.8 |
HIP 113918 |
21.79 |
| 2026-05-28 00:00 |
23:04:55.68 |
+60:06:07.5 |
HIP 113918 |
23.22 |
| 2026-05-28 12:00 |
23:04:58.58 |
+60:07:30.2 |
HIP 113853 |
22.53 |
| 2026-05-29 00:00 |
23:05:01.40 |
+60:08:53.0 |
HIP 113853 |
21.56 |
| 2026-05-29 12:00 |
23:05:04.13 |
+60:10:15.7 |
HIP 113853 |
20.63 |
| 2026-05-30 00:00 |
23:05:06.78 |
+60:11:38.4 |
HIP 113853 |
19.76 |
| 2026-05-30 12:00 |
23:05:09.34 |
+60:13:01.1 |
HIP 113853 |
18.94 |
| 2026-05-31 00:00 |
23:05:11.81 |
+60:14:23.8 |
HIP 113853 |
18.19 |
| 2026-05-31 12:00 |
23:05:14.19 |
+60:15:46.4 |
HIP 113853 |
17.51 |
| 2026-06-01 00:00 |
23:05:16.48 |
+60:17:09.0 |
HIP 113853 |
16.91 |
| 2026-06-01 12:00 |
23:05:18.69 |
+60:18:31.6 |
HIP 113853 |
16.40 |
| 2026-06-02 00:00 |
23:05:20.81 |
+60:19:54.2 |
HIP 113853 |
15.99 |