| Parameter |
Value |
| Designation |
C/2013 G7 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2014-03-18T16:01:39.025920Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:34Z |
| Obs used |
305 |
| NEO |
- |
| M1 |
6.000 |
| K1 |
12.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-07-23.0000000 |
| e |
0.99786135 |
| q (au) |
4.677407 |
| a (au) |
2187.083310 |
| i (deg) |
105.110084 |
| Ω (om, deg) |
48.402717 |
| ω (w, deg) |
218.263829 |
| M (ma, deg) |
359.997700 |
Magnitude
Scatter + Global Linear
$$
M_a = (8.939 + 3.225\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
8.939 |
| n |
3.225 |
| gf |
0.999 |
| gb |
-0.866 |
| k |
0.999 |
| δ90 |
9.999 |
| 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) |
| 2026-09-20 00:00 |
03:34:48.02 |
+07:43:50.1 |
HIP 16560 |
28.78 |
| 2026-09-20 12:00 |
03:34:45.36 |
+07:43:37.0 |
HIP 16560 |
28.11 |
| 2026-09-21 00:00 |
03:34:42.66 |
+07:43:23.9 |
HIP 16560 |
27.45 |
| 2026-09-21 12:00 |
03:34:39.93 |
+07:43:10.7 |
HIP 16560 |
26.77 |
| 2026-09-22 00:00 |
03:34:37.17 |
+07:42:57.4 |
HIP 16560 |
26.09 |
| 2026-09-22 12:00 |
03:34:34.37 |
+07:42:44.1 |
HIP 16560 |
25.41 |
| 2026-09-23 00:00 |
03:34:31.54 |
+07:42:30.8 |
HIP 16560 |
24.72 |
| 2026-09-23 12:00 |
03:34:28.68 |
+07:42:17.3 |
HIP 16560 |
24.02 |
| 2026-09-24 00:00 |
03:34:25.79 |
+07:42:03.9 |
HIP 16560 |
23.33 |
| 2026-09-24 12:00 |
03:34:22.86 |
+07:41:50.4 |
HIP 16560 |
22.63 |
| 2026-09-25 00:00 |
03:34:19.90 |
+07:41:36.8 |
HIP 16560 |
21.92 |
| 2026-09-25 12:00 |
03:34:16.91 |
+07:41:23.2 |
HIP 16560 |
21.22 |
| 2026-09-26 00:00 |
03:34:13.89 |
+07:41:09.5 |
HIP 16560 |
20.51 |
| 2026-09-26 12:00 |
03:34:10.83 |
+07:40:55.8 |
HIP 16560 |
19.80 |
| 2026-09-27 00:00 |
03:34:07.75 |
+07:40:42.1 |
HIP 16560 |
19.10 |
| 2026-09-27 12:00 |
03:34:04.63 |
+07:40:28.3 |
HIP 16560 |
18.39 |
| 2026-09-28 00:00 |
03:34:01.48 |
+07:40:14.4 |
HIP 16560 |
17.69 |
| 2026-09-28 12:00 |
03:33:58.30 |
+07:40:00.6 |
HIP 16560 |
17.00 |
| 2026-09-29 00:00 |
03:33:55.09 |
+07:39:46.7 |
HIP 16560 |
16.31 |
| 2026-09-29 12:00 |
03:33:51.85 |
+07:39:32.7 |
HIP 16560 |
15.62 |
| 2026-09-30 00:00 |
03:33:48.58 |
+07:39:18.7 |
HIP 16560 |
14.95 |
| 2026-09-30 12:00 |
03:33:45.28 |
+07:39:04.7 |
HIP 16560 |
14.29 |
| 2026-10-01 00:00 |
03:33:41.94 |
+07:38:50.7 |
HIP 16560 |
13.65 |
| 2026-10-01 12:00 |
03:33:38.58 |
+07:38:36.6 |
HIP 16560 |
13.03 |
| 2026-10-02 00:00 |
03:33:35.19 |
+07:38:22.5 |
HIP 16560 |
12.44 |
| 2026-10-02 12:00 |
03:33:31.77 |
+07:38:08.4 |
HIP 16560 |
11.87 |
| 2026-10-03 00:00 |
03:33:28.32 |
+07:37:54.2 |
HIP 16560 |
11.35 |
| 2026-10-03 12:00 |
03:33:24.84 |
+07:37:40.0 |
HIP 16560 |
10.87 |
| 2026-10-04 00:00 |
03:33:21.34 |
+07:37:25.8 |
HIP 16560 |
10.44 |
| 2026-10-04 12:00 |
03:33:17.80 |
+07:37:11.6 |
HIP 16560 |
10.07 |
| 2026-10-05 00:00 |
03:33:14.24 |
+07:36:57.4 |
HIP 16560 |
9.78 |
| 2026-10-05 12:00 |
03:33:10.64 |
+07:36:43.1 |
HIP 16560 |
9.56 |
| 2026-10-06 00:00 |
03:33:07.02 |
+07:36:28.8 |
HIP 16560 |
9.43 |
| 2026-10-06 12:00 |
03:33:03.37 |
+07:36:14.5 |
HIP 16560 |
9.39 |
| 2026-10-07 00:00 |
03:32:59.70 |
+07:36:00.2 |
HIP 16560 |
9.44 |
| 2026-10-07 12:00 |
03:32:56.00 |
+07:35:45.9 |
HIP 16560 |
9.60 |
| 2026-10-08 00:00 |
03:32:52.27 |
+07:35:31.6 |
HIP 16560 |
9.84 |
| 2026-10-08 12:00 |
03:32:48.51 |
+07:35:17.2 |
HIP 16560 |
10.17 |
| 2026-10-09 00:00 |
03:32:44.73 |
+07:35:02.9 |
HIP 16464 |
10.14 |
| 2026-10-09 12:00 |
03:32:40.92 |
+07:34:48.6 |
HIP 16464 |
9.17 |
| 2026-10-10 00:00 |
03:32:37.09 |
+07:34:34.2 |
HIP 16464 |
8.21 |
| 2026-10-10 12:00 |
03:32:33.23 |
+07:34:19.9 |
HIP 16464 |
7.24 |
| 2026-10-11 00:00 |
03:32:29.34 |
+07:34:05.5 |
HIP 16464 |
6.27 |