| Parameter |
Value |
| Designation |
C/2013 E1 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2013-06-12T02:48:47.306880Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:31Z |
| Obs used |
172 |
| NEO |
- |
| M1 |
6.600 |
| K1 |
8.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-06-11.0000000 |
| e |
1.00225843 |
| q (au) |
7.781630 |
| a (au) |
-3445.585444 |
| i (deg) |
158.720377 |
| Ω (om, deg) |
134.028821 |
| ω (w, deg) |
311.425764 |
| M (ma, deg) |
-0.000005 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.562 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.562 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.823 |
| k |
0.800 |
| 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) |
| 2026-07-29 00:00 |
04:32:27.30 |
+40:52:06.6 |
HIP 21217 |
7.00 |
| 2026-07-29 12:00 |
04:32:29.55 |
+40:52:30.0 |
HIP 21217 |
6.60 |
| 2026-07-30 00:00 |
04:32:31.76 |
+40:52:53.4 |
HIP 21217 |
6.22 |
| 2026-07-30 12:00 |
04:32:33.93 |
+40:53:16.8 |
HIP 21217 |
5.89 |
| 2026-07-31 00:00 |
04:32:36.06 |
+40:53:40.3 |
HIP 21217 |
5.60 |
| 2026-07-31 12:00 |
04:32:38.15 |
+40:54:03.8 |
HIP 21217 |
5.37 |
| 2026-08-01 00:00 |
04:32:40.20 |
+40:54:27.4 |
HIP 21217 |
5.19 |
| 2026-08-01 12:00 |
04:32:42.21 |
+40:54:51.0 |
HIP 21217 |
5.07 |
| 2026-08-02 00:00 |
04:32:44.18 |
+40:55:14.6 |
HIP 21217 |
5.01 |
| 2026-08-02 12:00 |
04:32:46.11 |
+40:55:38.2 |
HIP 21217 |
5.02 |
| 2026-08-03 00:00 |
04:32:48.00 |
+40:56:01.9 |
HIP 21217 |
5.09 |
| 2026-08-03 12:00 |
04:32:49.84 |
+40:56:25.6 |
HIP 21217 |
5.22 |
| 2026-08-04 00:00 |
04:32:51.64 |
+40:56:49.4 |
HIP 21217 |
5.40 |
| 2026-08-04 12:00 |
04:32:53.40 |
+40:57:13.1 |
HIP 21217 |
5.63 |
| 2026-08-05 00:00 |
04:32:55.12 |
+40:57:36.9 |
HIP 21217 |
5.89 |
| 2026-08-05 12:00 |
04:32:56.80 |
+40:58:00.8 |
HIP 21217 |
6.19 |
| 2026-08-06 00:00 |
04:32:58.43 |
+40:58:24.6 |
HIP 21217 |
6.52 |
| 2026-08-06 12:00 |
04:33:00.02 |
+40:58:48.5 |
HIP 21217 |
6.87 |
| 2026-08-07 00:00 |
04:33:01.57 |
+40:59:12.3 |
HIP 21217 |
7.24 |
| 2026-08-07 12:00 |
04:33:03.07 |
+40:59:36.2 |
HIP 21217 |
7.62 |
| 2026-08-08 00:00 |
04:33:04.53 |
+41:00:00.2 |
HIP 21217 |
8.02 |
| 2026-08-08 12:00 |
04:33:05.95 |
+41:00:24.1 |
HIP 21217 |
8.42 |
| 2026-08-09 00:00 |
04:33:07.32 |
+41:00:48.0 |
HIP 21217 |
8.83 |
| 2026-08-09 12:00 |
04:33:08.65 |
+41:01:12.0 |
HIP 21217 |
9.25 |
| 2026-08-10 00:00 |
04:33:09.93 |
+41:01:36.0 |
HIP 21217 |
9.67 |
| 2026-08-10 12:00 |
04:33:11.17 |
+41:02:00.0 |
HIP 21217 |
10.10 |
| 2026-08-11 00:00 |
04:33:12.36 |
+41:02:23.9 |
HIP 21217 |
10.52 |
| 2026-08-11 12:00 |
04:33:13.50 |
+41:02:47.9 |
HIP 21217 |
10.95 |
| 2026-08-12 00:00 |
04:33:14.60 |
+41:03:11.9 |
HIP 21217 |
11.38 |
| 2026-08-12 12:00 |
04:33:15.66 |
+41:03:35.9 |
HIP 21217 |
11.81 |
| 2026-08-13 00:00 |
04:33:16.67 |
+41:03:59.9 |
HIP 21217 |
12.24 |
| 2026-08-13 12:00 |
04:33:17.63 |
+41:04:23.9 |
HIP 21217 |
12.66 |
| 2026-08-14 00:00 |
04:33:18.54 |
+41:04:47.9 |
HIP 21217 |
13.09 |
| 2026-08-14 12:00 |
04:33:19.41 |
+41:05:11.9 |
HIP 21217 |
13.52 |
| 2026-08-15 00:00 |
04:33:20.23 |
+41:05:35.9 |
HIP 21217 |
13.94 |
| 2026-08-15 12:00 |
04:33:21.01 |
+41:05:59.8 |
HIP 21217 |
14.36 |
| 2026-08-16 00:00 |
04:33:21.73 |
+41:06:23.8 |
HIP 21217 |
14.78 |
| 2026-08-16 12:00 |
04:33:22.41 |
+41:06:47.8 |
HIP 21217 |
15.20 |
| 2026-08-17 00:00 |
04:33:23.05 |
+41:07:11.7 |
HIP 21217 |
15.61 |
| 2026-08-17 12:00 |
04:33:23.63 |
+41:07:35.6 |
HIP 21217 |
16.03 |
| 2026-08-18 00:00 |
04:33:24.17 |
+41:07:59.5 |
HIP 21217 |
16.44 |
| 2026-08-18 12:00 |
04:33:24.65 |
+41:08:23.4 |
HIP 21217 |
16.85 |
| 2026-08-19 00:00 |
04:33:25.09 |
+41:08:47.3 |
HIP 21217 |
17.25 |