C/2011 L1 (McNaught)
| 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) |
| 2026-02-03 00:00 |
22:30:29.09 |
+57:11:33.5 |
HIP 111088 |
2.42 |
| 2026-02-03 12:00 |
22:30:39.92 |
+57:11:16.5 |
HIP 111088 |
3.65 |
| 2026-02-04 00:00 |
22:30:50.77 |
+57:11:00.2 |
HIP 111088 |
5.02 |
| 2026-02-04 12:00 |
22:31:01.64 |
+57:10:44.5 |
HIP 111088 |
6.45 |
| 2026-02-05 00:00 |
22:31:12.54 |
+57:10:29.5 |
HIP 111088 |
7.90 |
| 2026-02-05 12:00 |
22:31:23.47 |
+57:10:15.2 |
HIP 111088 |
9.36 |
| 2026-02-06 00:00 |
22:31:34.42 |
+57:10:01.6 |
HIP 111088 |
10.83 |
| 2026-02-06 12:00 |
22:31:45.39 |
+57:09:48.6 |
HIP 111088 |
12.31 |
| 2026-02-07 00:00 |
22:31:56.38 |
+57:09:36.4 |
HIP 111088 |
13.80 |
| 2026-02-07 12:00 |
22:32:07.40 |
+57:09:24.7 |
HIP 111088 |
15.29 |
| 2026-02-08 00:00 |
22:32:18.44 |
+57:09:13.8 |
HIP 111088 |
16.78 |
| 2026-02-08 12:00 |
22:32:29.50 |
+57:09:03.5 |
HIP 111088 |
18.27 |
| 2026-02-09 00:00 |
22:32:40.58 |
+57:08:53.9 |
HIP 111457 |
18.31 |
| 2026-02-09 12:00 |
22:32:51.68 |
+57:08:45.0 |
HIP 111457 |
16.95 |
| 2026-02-10 00:00 |
22:33:02.80 |
+57:08:36.8 |
HIP 111457 |
15.62 |
| 2026-02-10 12:00 |
22:33:13.94 |
+57:08:29.2 |
HIP 111457 |
14.31 |
| 2026-02-11 00:00 |
22:33:25.10 |
+57:08:22.3 |
HIP 111457 |
13.04 |
| 2026-02-11 12:00 |
22:33:36.28 |
+57:08:16.1 |
HIP 111457 |
11.82 |
| 2026-02-12 00:00 |
22:33:47.47 |
+57:08:10.6 |
HIP 111457 |
10.67 |
| 2026-02-12 12:00 |
22:33:58.68 |
+57:08:05.7 |
HIP 111457 |
9.61 |
| 2026-02-13 00:00 |
22:34:09.91 |
+57:08:01.5 |
HIP 111457 |
8.67 |
| 2026-02-13 12:00 |
22:34:21.15 |
+57:07:58.0 |
HIP 111457 |
7.91 |
| 2026-02-14 00:00 |
22:34:32.40 |
+57:07:55.2 |
HIP 111457 |
7.38 |
| 2026-02-14 12:00 |
22:34:43.67 |
+57:07:53.0 |
HIP 111457 |
7.13 |
| 2026-02-15 00:00 |
22:34:54.95 |
+57:07:51.5 |
HIP 111457 |
7.19 |
| 2026-02-15 12:00 |
22:35:06.25 |
+57:07:50.7 |
HIP 111457 |
7.56 |
| 2026-02-16 00:00 |
22:35:17.56 |
+57:07:50.6 |
HIP 111457 |
8.19 |
| 2026-02-16 12:00 |
22:35:28.88 |
+57:07:51.1 |
HIP 111457 |
9.03 |
| 2026-02-17 00:00 |
22:35:40.21 |
+57:07:52.3 |
HIP 111457 |
10.03 |
| 2026-02-17 12:00 |
22:35:51.55 |
+57:07:54.2 |
HIP 111457 |
11.14 |
| 2026-02-18 00:00 |
22:36:02.90 |
+57:07:56.7 |
HIP 111457 |
12.34 |
| 2026-02-18 12:00 |
22:36:14.27 |
+57:08:00.0 |
HIP 111457 |
13.61 |
| 2026-02-19 00:00 |
22:36:25.64 |
+57:08:03.8 |
HIP 111633 |
14.25 |
| 2026-02-19 12:00 |
22:36:37.01 |
+57:08:08.4 |
HIP 111633 |
13.98 |
| 2026-02-20 00:00 |
22:36:48.40 |
+57:08:13.6 |
HIP 111633 |
13.90 |
| 2026-02-20 12:00 |
22:36:59.79 |
+57:08:19.5 |
HIP 111633 |
14.00 |
| 2026-02-21 00:00 |
22:37:11.19 |
+57:08:26.1 |
HIP 111633 |
14.28 |
| 2026-02-21 12:00 |
22:37:22.59 |
+57:08:33.3 |
HIP 111633 |
14.73 |
| 2026-02-22 00:00 |
22:37:34.00 |
+57:08:41.2 |
HIP 111633 |
15.34 |
| 2026-02-22 12:00 |
22:37:45.41 |
+57:08:49.8 |
HIP 111633 |
16.08 |
| 2026-02-23 00:00 |
22:37:56.83 |
+57:08:59.0 |
HIP 111854 |
15.97 |
| 2026-02-23 12:00 |
22:38:08.24 |
+57:09:08.8 |
HIP 111854 |
14.72 |
| 2026-02-24 00:00 |
22:38:19.67 |
+57:09:19.4 |
HIP 111854 |
13.53 |