| Parameter |
Value |
| Designation |
C/2013 J3 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2013-02-22T21:02:36.003840Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:35Z |
| Obs used |
105 |
| NEO |
- |
| M1 |
6.900 |
| K1 |
14.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-07-03.0000000 |
| e |
0.99795766 |
| q (au) |
3.988692 |
| a (au) |
1952.998658 |
| i (deg) |
118.225398 |
| Ω (om, deg) |
200.757159 |
| ω (w, deg) |
320.958517 |
| M (ma, deg) |
0.001486 |
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 |
-1.000 |
| 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) |
| 2026-09-20 00:00 |
08:41:45.34 |
+82:36:28.6 |
HIP 42671 |
0.24 |
| 2026-09-20 12:00 |
08:42:02.20 |
+82:37:09.4 |
HIP 42671 |
0.63 |
| 2026-09-21 00:00 |
08:42:18.90 |
+82:37:50.6 |
HIP 42671 |
1.50 |
| 2026-09-21 12:00 |
08:42:35.46 |
+82:38:32.1 |
HIP 42671 |
2.37 |
| 2026-09-22 00:00 |
08:42:51.87 |
+82:39:13.9 |
HIP 42671 |
3.25 |
| 2026-09-22 12:00 |
08:43:08.12 |
+82:39:56.0 |
HIP 42671 |
4.12 |
| 2026-09-23 00:00 |
08:43:24.23 |
+82:40:38.5 |
HIP 42671 |
4.99 |
| 2026-09-23 12:00 |
08:43:40.17 |
+82:41:21.2 |
HIP 42671 |
5.87 |
| 2026-09-24 00:00 |
08:43:55.96 |
+82:42:04.3 |
HIP 42671 |
6.74 |
| 2026-09-24 12:00 |
08:44:11.59 |
+82:42:47.7 |
HIP 42671 |
7.62 |
| 2026-09-25 00:00 |
08:44:27.06 |
+82:43:31.4 |
HIP 42671 |
8.50 |
| 2026-09-25 12:00 |
08:44:42.38 |
+82:44:15.4 |
HIP 42671 |
9.37 |
| 2026-09-26 00:00 |
08:44:57.52 |
+82:44:59.7 |
HIP 42671 |
10.25 |
| 2026-09-26 12:00 |
08:45:12.51 |
+82:45:44.3 |
HIP 42671 |
11.13 |
| 2026-09-27 00:00 |
08:45:27.32 |
+82:46:29.2 |
HIP 42671 |
12.01 |
| 2026-09-27 12:00 |
08:45:41.97 |
+82:47:14.5 |
HIP 42671 |
12.89 |
| 2026-09-28 00:00 |
08:45:56.45 |
+82:48:00.0 |
HIP 42671 |
13.78 |
| 2026-09-28 12:00 |
08:46:10.76 |
+82:48:45.8 |
HIP 42671 |
14.66 |
| 2026-09-29 00:00 |
08:46:24.89 |
+82:49:32.0 |
HIP 42671 |
15.54 |
| 2026-09-29 12:00 |
08:46:38.85 |
+82:50:18.4 |
HIP 42671 |
16.43 |
| 2026-09-30 00:00 |
08:46:52.64 |
+82:51:05.1 |
HIP 42671 |
17.31 |
| 2026-09-30 12:00 |
08:47:06.24 |
+82:51:52.1 |
HIP 42671 |
18.20 |
| 2026-10-01 00:00 |
08:47:19.67 |
+82:52:39.4 |
HIP 42671 |
19.08 |
| 2026-10-01 12:00 |
08:47:32.91 |
+82:53:27.0 |
HIP 42671 |
19.97 |
| 2026-10-02 00:00 |
08:47:45.97 |
+82:54:14.9 |
HIP 42671 |
20.86 |
| 2026-10-02 12:00 |
08:47:58.84 |
+82:55:03.1 |
HIP 42671 |
21.75 |
| 2026-10-03 00:00 |
08:48:11.52 |
+82:55:51.5 |
HIP 42671 |
22.64 |
| 2026-10-03 12:00 |
08:48:24.01 |
+82:56:40.3 |
HIP 42671 |
23.53 |
| 2026-10-04 00:00 |
08:48:36.31 |
+82:57:29.3 |
HIP 42671 |
24.42 |
| 2026-10-04 12:00 |
08:48:48.41 |
+82:58:18.6 |
HIP 42671 |
25.32 |
| 2026-10-05 00:00 |
08:49:00.32 |
+82:59:08.2 |
HIP 44187 |
26.11 |
| 2026-10-05 12:00 |
08:49:12.02 |
+82:59:58.1 |
HIP 44187 |
26.33 |
| 2026-10-06 00:00 |
08:49:23.53 |
+83:00:48.2 |
HIP 44187 |
26.58 |
| 2026-10-06 12:00 |
08:49:34.83 |
+83:01:38.6 |
HIP 44187 |
26.88 |
| 2026-10-07 00:00 |
08:49:45.92 |
+83:02:29.3 |
HIP 44187 |
27.21 |
| 2026-10-07 12:00 |
08:49:56.80 |
+83:03:20.2 |
HIP 44187 |
27.57 |
| 2026-10-08 00:00 |
08:50:07.48 |
+83:04:11.4 |
HIP 44187 |
27.97 |
| 2026-10-08 12:00 |
08:50:17.94 |
+83:05:02.9 |
HIP 44187 |
28.40 |
| 2026-10-09 00:00 |
08:50:28.18 |
+83:05:54.6 |
HIP 44187 |
28.87 |
| 2026-10-09 12:00 |
08:50:38.21 |
+83:06:46.6 |
HIP 44187 |
29.36 |
| 2026-10-10 00:00 |
08:50:48.01 |
+83:07:38.8 |
HIP 44187 |
29.88 |
| 2026-10-10 12:00 |
08:50:57.59 |
+83:08:31.3 |
HIP 44805 |
30.31 |
| 2026-10-11 00:00 |
08:51:06.95 |
+83:09:24.1 |
HIP 44805 |
29.95 |