| Parameter |
Value |
| Designation |
C/2011 R1 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2012-10-19T14:54:08.481600Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:56Z |
| Obs used |
1454 |
| NEO |
- |
| M1 |
9.900 |
| K1 |
6.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2012-10-24.0000000 |
| e |
1.00074117 |
| q (au) |
2.079571 |
| a (au) |
-2805.810838 |
| i (deg) |
116.196842 |
| Ω (om, deg) |
221.408458 |
| ω (w, deg) |
308.861192 |
| M (ma, deg) |
0.000029 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.666 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.666 |
| n |
2.000 |
| gf |
1.000 |
| gb |
-0.500 |
| k |
1.000 |
| 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 |
| 2010-10-11 |
2012-04-01 |
+7.1902 |
-6.300 |
| 2012-04-01 |
2012-10-15 |
-6.1910 |
-0.092 |
| 2012-12-23 |
2013-02-17 |
+39.6659 |
-16.680 |
| 2013-02-17 |
2014-04-11 |
+3.1359 |
-1.430 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
11:03:47.54 |
+81:10:56.5 |
HIP 53819 |
8.49 |
| 2026-03-26 12:00 |
11:03:23.60 |
+81:10:44.7 |
HIP 53819 |
7.86 |
| 2026-03-27 00:00 |
11:02:59.76 |
+81:10:32.4 |
HIP 53819 |
7.31 |
| 2026-03-27 12:00 |
11:02:36.02 |
+81:10:19.4 |
HIP 53819 |
6.85 |
| 2026-03-28 00:00 |
11:02:12.40 |
+81:10:05.9 |
HIP 53819 |
6.51 |
| 2026-03-28 12:00 |
11:01:48.88 |
+81:09:51.8 |
HIP 53819 |
6.29 |
| 2026-03-29 00:00 |
11:01:25.47 |
+81:09:37.2 |
HIP 53819 |
6.21 |
| 2026-03-29 12:00 |
11:01:02.18 |
+81:09:22.0 |
HIP 53819 |
6.28 |
| 2026-03-30 00:00 |
11:00:39.01 |
+81:09:06.2 |
HIP 53819 |
6.50 |
| 2026-03-30 12:00 |
11:00:15.96 |
+81:08:49.9 |
HIP 53819 |
6.84 |
| 2026-03-31 00:00 |
10:59:53.03 |
+81:08:33.1 |
HIP 53819 |
7.29 |
| 2026-03-31 12:00 |
10:59:30.22 |
+81:08:15.7 |
HIP 53819 |
7.83 |
| 2026-04-01 00:00 |
10:59:07.54 |
+81:07:57.8 |
HIP 53819 |
8.44 |
| 2026-04-01 12:00 |
10:58:44.99 |
+81:07:39.3 |
HIP 53819 |
9.11 |
| 2026-04-02 00:00 |
10:58:22.57 |
+81:07:20.3 |
HIP 53819 |
9.82 |
| 2026-04-02 12:00 |
10:58:00.29 |
+81:07:00.7 |
HIP 53819 |
10.58 |
| 2026-04-03 00:00 |
10:57:38.14 |
+81:06:40.7 |
HIP 53819 |
11.35 |
| 2026-04-03 12:00 |
10:57:16.13 |
+81:06:20.1 |
HIP 53819 |
12.16 |
| 2026-04-04 00:00 |
10:56:54.25 |
+81:05:59.0 |
HIP 53819 |
12.97 |
| 2026-04-04 12:00 |
10:56:32.52 |
+81:05:37.3 |
HIP 53819 |
13.81 |
| 2026-04-05 00:00 |
10:56:10.93 |
+81:05:15.2 |
HIP 53819 |
14.65 |
| 2026-04-05 12:00 |
10:55:49.49 |
+81:04:52.5 |
HIP 53819 |
15.51 |
| 2026-04-06 00:00 |
10:55:28.20 |
+81:04:29.3 |
HIP 53819 |
16.37 |
| 2026-04-06 12:00 |
10:55:07.06 |
+81:04:05.7 |
HIP 53819 |
17.24 |
| 2026-04-07 00:00 |
10:54:46.07 |
+81:03:41.5 |
HIP 53819 |
18.12 |
| 2026-04-07 12:00 |
10:54:25.23 |
+81:03:16.8 |
HIP 53819 |
18.99 |
| 2026-04-08 00:00 |
10:54:04.55 |
+81:02:51.6 |
HIP 53819 |
19.88 |
| 2026-04-08 12:00 |
10:53:44.02 |
+81:02:26.0 |
HIP 53819 |
20.76 |
| 2026-04-09 00:00 |
10:53:23.66 |
+81:01:59.8 |
HIP 53819 |
21.65 |
| 2026-04-09 12:00 |
10:53:03.45 |
+81:01:33.2 |
HIP 53819 |
22.54 |
| 2026-04-10 00:00 |
10:52:43.41 |
+81:01:06.1 |
HIP 53819 |
23.43 |
| 2026-04-10 12:00 |
10:52:23.53 |
+81:00:38.5 |
HIP 53819 |
24.32 |
| 2026-04-11 00:00 |
10:52:03.82 |
+81:00:10.5 |
HIP 53819 |
25.22 |
| 2026-04-11 12:00 |
10:51:44.28 |
+80:59:41.9 |
HIP 53819 |
26.11 |
| 2026-04-12 00:00 |
10:51:24.91 |
+80:59:12.9 |
HIP 53819 |
27.00 |
| 2026-04-12 12:00 |
10:51:05.71 |
+80:58:43.5 |
HIP 53819 |
27.90 |
| 2026-04-13 00:00 |
10:50:46.68 |
+80:58:13.6 |
HIP 53819 |
28.79 |
| 2026-04-13 12:00 |
10:50:27.82 |
+80:57:43.2 |
HIP 53819 |
29.69 |
| 2026-04-14 00:00 |
10:50:09.14 |
+80:57:12.4 |
HIP 53819 |
30.58 |
| 2026-04-14 12:00 |
10:49:50.64 |
+80:56:41.2 |
HIP 53819 |
31.48 |
| 2026-04-15 00:00 |
10:49:32.32 |
+80:56:09.5 |
HIP 53819 |
32.37 |
| 2026-04-15 12:00 |
10:49:14.18 |
+80:55:37.4 |
HIP 52464 |
33.08 |
| 2026-04-16 00:00 |
10:48:56.22 |
+80:55:04.8 |
HIP 52464 |
32.29 |