| 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 |
-0.998 |
| 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) |
| 2026-07-29 00:00 |
10:49:49.28 |
+78:15:24.6 |
HIP 53572 |
36.47 |
| 2026-07-29 12:00 |
10:50:02.42 |
+78:14:50.8 |
HIP 53572 |
35.61 |
| 2026-07-30 00:00 |
10:50:15.62 |
+78:14:17.3 |
HIP 53572 |
34.74 |
| 2026-07-30 12:00 |
10:50:28.88 |
+78:13:44.1 |
HIP 53572 |
33.88 |
| 2026-07-31 00:00 |
10:50:42.20 |
+78:13:11.1 |
HIP 53572 |
33.02 |
| 2026-07-31 12:00 |
10:50:55.58 |
+78:12:38.5 |
HIP 53572 |
32.16 |
| 2026-08-01 00:00 |
10:51:09.01 |
+78:12:06.2 |
HIP 53572 |
31.30 |
| 2026-08-01 12:00 |
10:51:22.51 |
+78:11:34.3 |
HIP 53572 |
30.45 |
| 2026-08-02 00:00 |
10:51:36.06 |
+78:11:02.6 |
HIP 53572 |
29.60 |
| 2026-08-02 12:00 |
10:51:49.67 |
+78:10:31.2 |
HIP 53572 |
28.75 |
| 2026-08-03 00:00 |
10:52:03.34 |
+78:10:00.2 |
HIP 53572 |
27.90 |
| 2026-08-03 12:00 |
10:52:17.06 |
+78:09:29.4 |
HIP 53572 |
27.06 |
| 2026-08-04 00:00 |
10:52:30.83 |
+78:08:59.0 |
HIP 53572 |
26.23 |
| 2026-08-04 12:00 |
10:52:44.66 |
+78:08:28.9 |
HIP 53572 |
25.40 |
| 2026-08-05 00:00 |
10:52:58.53 |
+78:07:59.1 |
HIP 53572 |
24.57 |
| 2026-08-05 12:00 |
10:53:12.47 |
+78:07:29.7 |
HIP 53572 |
23.75 |
| 2026-08-06 00:00 |
10:53:26.45 |
+78:07:00.5 |
HIP 53572 |
22.94 |
| 2026-08-06 12:00 |
10:53:40.48 |
+78:06:31.7 |
HIP 53572 |
22.13 |
| 2026-08-07 00:00 |
10:53:54.57 |
+78:06:03.2 |
HIP 53572 |
21.33 |
| 2026-08-07 12:00 |
10:54:08.70 |
+78:05:35.1 |
HIP 53572 |
20.55 |
| 2026-08-08 00:00 |
10:54:22.88 |
+78:05:07.3 |
HIP 53572 |
19.77 |
| 2026-08-08 12:00 |
10:54:37.11 |
+78:04:39.8 |
HIP 53572 |
19.00 |
| 2026-08-09 00:00 |
10:54:51.38 |
+78:04:12.6 |
HIP 53572 |
18.24 |
| 2026-08-09 12:00 |
10:55:05.70 |
+78:03:45.8 |
HIP 53572 |
17.50 |
| 2026-08-10 00:00 |
10:55:20.07 |
+78:03:19.4 |
HIP 53572 |
16.78 |
| 2026-08-10 12:00 |
10:55:34.48 |
+78:02:53.2 |
HIP 53572 |
16.07 |
| 2026-08-11 00:00 |
10:55:48.93 |
+78:02:27.5 |
HIP 53572 |
15.39 |
| 2026-08-11 12:00 |
10:56:03.43 |
+78:02:02.0 |
HIP 53572 |
14.73 |
| 2026-08-12 00:00 |
10:56:17.97 |
+78:01:36.9 |
HIP 53572 |
14.10 |
| 2026-08-12 12:00 |
10:56:32.55 |
+78:01:12.2 |
HIP 53572 |
13.49 |
| 2026-08-13 00:00 |
10:56:47.17 |
+78:00:47.8 |
HIP 53572 |
12.93 |
| 2026-08-13 12:00 |
10:57:01.83 |
+78:00:23.8 |
HIP 53572 |
12.40 |
| 2026-08-14 00:00 |
10:57:16.53 |
+78:00:00.1 |
HIP 53572 |
11.92 |
| 2026-08-14 12:00 |
10:57:31.27 |
+77:59:36.8 |
HIP 53572 |
11.49 |
| 2026-08-15 00:00 |
10:57:46.05 |
+77:59:13.8 |
HIP 53572 |
11.11 |
| 2026-08-15 12:00 |
10:58:00.86 |
+77:58:51.2 |
HIP 53572 |
10.80 |
| 2026-08-16 00:00 |
10:58:15.70 |
+77:58:28.9 |
HIP 53572 |
10.56 |
| 2026-08-16 12:00 |
10:58:30.58 |
+77:58:07.1 |
HIP 53572 |
10.39 |
| 2026-08-17 00:00 |
10:58:45.49 |
+77:57:45.5 |
HIP 53572 |
10.29 |
| 2026-08-17 12:00 |
10:59:00.44 |
+77:57:24.4 |
HIP 53572 |
10.28 |
| 2026-08-18 00:00 |
10:59:15.42 |
+77:57:03.6 |
HIP 53572 |
10.34 |
| 2026-08-18 12:00 |
10:59:30.43 |
+77:56:43.1 |
HIP 53572 |
10.48 |
| 2026-08-19 00:00 |
10:59:45.47 |
+77:56:23.1 |
HIP 53761 |
10.19 |