| Parameter |
Value |
| Designation |
C/2013 G2 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2012-12-06T08:24:02.825280Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:32Z |
| Obs used |
111 |
| NEO |
- |
| M1 |
13.700 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-05-24.0000000 |
| e |
1.00017667 |
| q (au) |
2.154122 |
| a (au) |
-12193.190355 |
| i (deg) |
96.001965 |
| Ω (om, deg) |
274.112530 |
| ω (w, deg) |
293.912193 |
| M (ma, deg) |
0.000123 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.810 + 2.787\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.810 |
| n |
2.787 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
17:26:31.20 |
+60:03:52.2 |
HIP 85290 |
6.29 |
| 2026-05-12 12:00 |
17:26:24.32 |
+60:04:27.4 |
HIP 85290 |
5.58 |
| 2026-05-13 00:00 |
17:26:17.41 |
+60:05:02.0 |
HIP 85290 |
4.98 |
| 2026-05-13 12:00 |
17:26:10.46 |
+60:05:36.3 |
HIP 85290 |
4.53 |
| 2026-05-14 00:00 |
17:26:03.47 |
+60:06:10.0 |
HIP 85290 |
4.27 |
| 2026-05-14 12:00 |
17:25:56.45 |
+60:06:43.3 |
HIP 85290 |
4.26 |
| 2026-05-15 00:00 |
17:25:49.39 |
+60:07:16.1 |
HIP 85290 |
4.48 |
| 2026-05-15 12:00 |
17:25:42.30 |
+60:07:48.5 |
HIP 85290 |
4.91 |
| 2026-05-16 00:00 |
17:25:35.17 |
+60:08:20.4 |
HIP 85290 |
5.49 |
| 2026-05-16 12:00 |
17:25:28.00 |
+60:08:51.8 |
HIP 85290 |
6.19 |
| 2026-05-17 00:00 |
17:25:20.81 |
+60:09:22.7 |
HIP 85290 |
6.97 |
| 2026-05-17 12:00 |
17:25:13.58 |
+60:09:53.2 |
HIP 85290 |
7.80 |
| 2026-05-18 00:00 |
17:25:06.32 |
+60:10:23.2 |
HIP 85290 |
8.67 |
| 2026-05-18 12:00 |
17:24:59.03 |
+60:10:52.7 |
HIP 85290 |
9.56 |
| 2026-05-19 00:00 |
17:24:51.70 |
+60:11:21.7 |
HIP 85290 |
10.48 |
| 2026-05-19 12:00 |
17:24:44.35 |
+60:11:50.2 |
HIP 85290 |
11.41 |
| 2026-05-20 00:00 |
17:24:36.97 |
+60:12:18.2 |
HIP 85290 |
12.36 |
| 2026-05-20 12:00 |
17:24:29.55 |
+60:12:45.8 |
HIP 85290 |
13.31 |
| 2026-05-21 00:00 |
17:24:22.11 |
+60:13:12.8 |
HIP 85290 |
14.27 |
| 2026-05-21 12:00 |
17:24:14.65 |
+60:13:39.4 |
HIP 85290 |
15.24 |
| 2026-05-22 00:00 |
17:24:07.15 |
+60:14:05.4 |
HIP 85290 |
16.21 |
| 2026-05-22 12:00 |
17:23:59.63 |
+60:14:31.0 |
HIP 85290 |
17.18 |
| 2026-05-23 00:00 |
17:23:52.09 |
+60:14:56.1 |
HIP 85290 |
18.16 |
| 2026-05-23 12:00 |
17:23:44.52 |
+60:15:20.6 |
HIP 85290 |
19.14 |
| 2026-05-24 00:00 |
17:23:36.92 |
+60:15:44.7 |
HIP 85290 |
20.12 |
| 2026-05-24 12:00 |
17:23:29.30 |
+60:16:08.3 |
HIP 85290 |
21.10 |
| 2026-05-25 00:00 |
17:23:21.66 |
+60:16:31.3 |
HIP 85290 |
22.08 |
| 2026-05-25 12:00 |
17:23:14.00 |
+60:16:53.9 |
HIP 85290 |
23.06 |
| 2026-05-26 00:00 |
17:23:06.31 |
+60:17:16.0 |
HIP 85290 |
24.05 |
| 2026-05-26 12:00 |
17:22:58.61 |
+60:17:37.5 |
HIP 85290 |
25.03 |
| 2026-05-27 00:00 |
17:22:50.88 |
+60:17:58.5 |
HIP 85290 |
26.01 |
| 2026-05-27 12:00 |
17:22:43.14 |
+60:18:19.1 |
HIP 85144 |
26.97 |
| 2026-05-28 00:00 |
17:22:35.37 |
+60:18:39.1 |
HIP 85144 |
27.01 |
| 2026-05-28 12:00 |
17:22:27.59 |
+60:18:58.6 |
HIP 85144 |
27.10 |
| 2026-05-29 00:00 |
17:22:19.78 |
+60:19:17.6 |
HIP 85144 |
27.23 |
| 2026-05-29 12:00 |
17:22:11.96 |
+60:19:36.1 |
HIP 85144 |
27.41 |
| 2026-05-30 00:00 |
17:22:04.13 |
+60:19:54.1 |
HIP 85144 |
27.63 |
| 2026-05-30 12:00 |
17:21:56.28 |
+60:20:11.6 |
HIP 85144 |
27.89 |
| 2026-05-31 00:00 |
17:21:48.41 |
+60:20:28.5 |
HIP 85144 |
28.20 |
| 2026-05-31 12:00 |
17:21:40.53 |
+60:20:45.0 |
HIP 85144 |
28.54 |
| 2026-06-01 00:00 |
17:21:32.63 |
+60:21:00.9 |
HIP 85144 |
28.93 |
| 2026-06-01 12:00 |
17:21:24.72 |
+60:21:16.3 |
HIP 85144 |
29.35 |
| 2026-06-02 00:00 |
17:21:16.80 |
+60:21:31.2 |
HIP 85144 |
29.81 |