C/2013 G7 (McNaught)
| 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 |
1.000 |
| gb |
-0.866 |
| 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
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
03:20:55.93 |
+06:00:17.5 |
HIP 15542 |
16.45 |
| 2026-02-03 12:00 |
03:20:54.97 |
+06:00:37.3 |
HIP 15542 |
16.04 |
| 2026-02-04 00:00 |
03:20:54.04 |
+06:00:57.3 |
HIP 15542 |
15.64 |
| 2026-02-04 12:00 |
03:20:53.15 |
+06:01:17.5 |
HIP 15542 |
15.24 |
| 2026-02-05 00:00 |
03:20:52.31 |
+06:01:37.8 |
HIP 15542 |
14.84 |
| 2026-02-05 12:00 |
03:20:51.50 |
+06:01:58.2 |
HIP 15542 |
14.45 |
| 2026-02-06 00:00 |
03:20:50.74 |
+06:02:18.9 |
HIP 15542 |
14.06 |
| 2026-02-06 12:00 |
03:20:50.02 |
+06:02:39.6 |
HIP 15542 |
13.68 |
| 2026-02-07 00:00 |
03:20:49.33 |
+06:03:00.5 |
HIP 15542 |
13.31 |
| 2026-02-07 12:00 |
03:20:48.69 |
+06:03:21.6 |
HIP 15542 |
12.93 |
| 2026-02-08 00:00 |
03:20:48.09 |
+06:03:42.8 |
HIP 15542 |
12.57 |
| 2026-02-08 12:00 |
03:20:47.52 |
+06:04:04.1 |
HIP 15542 |
12.20 |
| 2026-02-09 00:00 |
03:20:47.00 |
+06:04:25.6 |
HIP 15542 |
11.85 |
| 2026-02-09 12:00 |
03:20:46.52 |
+06:04:47.2 |
HIP 15542 |
11.50 |
| 2026-02-10 00:00 |
03:20:46.08 |
+06:05:09.0 |
HIP 15542 |
11.16 |
| 2026-02-10 12:00 |
03:20:45.68 |
+06:05:30.9 |
HIP 15542 |
10.83 |
| 2026-02-11 00:00 |
03:20:45.32 |
+06:05:52.9 |
HIP 15542 |
10.50 |
| 2026-02-11 12:00 |
03:20:45.00 |
+06:06:15.1 |
HIP 15542 |
10.19 |
| 2026-02-12 00:00 |
03:20:44.72 |
+06:06:37.5 |
HIP 15542 |
9.88 |
| 2026-02-12 12:00 |
03:20:44.48 |
+06:07:00.0 |
HIP 15542 |
9.59 |
| 2026-02-13 00:00 |
03:20:44.28 |
+06:07:22.5 |
HIP 15542 |
9.31 |
| 2026-02-13 12:00 |
03:20:44.12 |
+06:07:45.2 |
HIP 15542 |
9.04 |
| 2026-02-14 00:00 |
03:20:44.00 |
+06:08:08.1 |
HIP 15542 |
8.79 |
| 2026-02-14 12:00 |
03:20:43.92 |
+06:08:31.0 |
HIP 15542 |
8.55 |
| 2026-02-15 00:00 |
03:20:43.88 |
+06:08:54.2 |
HIP 15542 |
8.34 |
| 2026-02-15 12:00 |
03:20:43.88 |
+06:09:17.4 |
HIP 15542 |
8.14 |
| 2026-02-16 00:00 |
03:20:43.92 |
+06:09:40.8 |
HIP 15542 |
7.96 |
| 2026-02-16 12:00 |
03:20:44.00 |
+06:10:04.2 |
HIP 15542 |
7.81 |
| 2026-02-17 00:00 |
03:20:44.12 |
+06:10:27.8 |
HIP 15542 |
7.68 |
| 2026-02-17 12:00 |
03:20:44.28 |
+06:10:51.6 |
HIP 15542 |
7.59 |
| 2026-02-18 00:00 |
03:20:44.47 |
+06:11:15.4 |
HIP 15542 |
7.52 |
| 2026-02-18 12:00 |
03:20:44.71 |
+06:11:39.4 |
HIP 15542 |
7.47 |
| 2026-02-19 00:00 |
03:20:44.99 |
+06:12:03.5 |
HIP 15542 |
7.46 |
| 2026-02-19 12:00 |
03:20:45.30 |
+06:12:27.6 |
HIP 15542 |
7.49 |
| 2026-02-20 00:00 |
03:20:45.66 |
+06:12:52.0 |
HIP 15542 |
7.54 |
| 2026-02-20 12:00 |
03:20:46.05 |
+06:13:16.4 |
HIP 15542 |
7.63 |
| 2026-02-21 00:00 |
03:20:46.49 |
+06:13:40.9 |
HIP 15542 |
7.74 |
| 2026-02-21 12:00 |
03:20:46.96 |
+06:14:05.5 |
HIP 15542 |
7.89 |
| 2026-02-22 00:00 |
03:20:47.47 |
+06:14:30.3 |
HIP 15542 |
8.07 |
| 2026-02-22 12:00 |
03:20:48.02 |
+06:14:55.1 |
HIP 15542 |
8.28 |
| 2026-02-23 00:00 |
03:20:48.60 |
+06:15:20.1 |
HIP 15542 |
8.51 |
| 2026-02-23 12:00 |
03:20:49.23 |
+06:15:45.1 |
HIP 15542 |
8.77 |
| 2026-02-24 00:00 |
03:20:49.89 |
+06:16:10.3 |
HIP 15542 |
9.05 |