| Parameter |
Value |
| Designation |
P/2013 J2 (McNaught) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2013-08-22T23:57:25.464960Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:35Z |
| Obs used |
1606 |
| NEO |
- |
| M1 |
12.800 |
| K1 |
7.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-09-18.0000000 |
| e |
0.65614970 |
| q (au) |
2.147830 |
| a (au) |
6.246411 |
| i (deg) |
15.495560 |
| Ω (om, deg) |
289.393509 |
| ω (w, deg) |
37.889335 |
| M (ma, deg) |
1.641578 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.547 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.547 |
| n |
2.000 |
| gf |
0.999 |
| gb |
-0.947 |
| 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) |
| 2026-09-25 00:00 |
12:19:00.79 |
-16:40:07.4 |
HIP 59964 |
23.22 |
| 2026-09-25 12:00 |
12:19:20.03 |
-16:42:02.5 |
HIP 59964 |
25.38 |
| 2026-09-26 00:00 |
12:19:39.29 |
-16:43:58.2 |
HIP 60086 |
27.97 |
| 2026-09-26 12:00 |
12:19:58.57 |
-16:45:54.2 |
HIP 60086 |
30.97 |
| 2026-09-27 00:00 |
12:20:17.87 |
-16:47:50.8 |
HIP 60086 |
34.45 |
| 2026-09-27 12:00 |
12:20:37.19 |
-16:49:47.8 |
HIP 60086 |
38.28 |
| 2026-09-28 00:00 |
12:20:56.52 |
-16:51:45.3 |
HIP 60452 |
39.74 |
| 2026-09-28 12:00 |
12:21:15.87 |
-16:53:43.2 |
HIP 60452 |
35.96 |
| 2026-09-29 00:00 |
12:21:35.23 |
-16:55:41.5 |
HIP 60452 |
32.53 |
| 2026-09-29 12:00 |
12:21:54.61 |
-16:57:40.3 |
HIP 60452 |
29.56 |
| 2026-09-30 00:00 |
12:22:14.00 |
-16:59:39.6 |
HIP 60452 |
27.21 |
| 2026-09-30 12:00 |
12:22:33.41 |
-17:01:39.3 |
HIP 60452 |
25.66 |
| 2026-10-01 00:00 |
12:22:52.83 |
-17:03:39.4 |
HIP 60452 |
25.06 |
| 2026-10-01 12:00 |
12:23:12.27 |
-17:05:39.9 |
HIP 60452 |
25.47 |
| 2026-10-02 00:00 |
12:23:31.72 |
-17:07:40.9 |
HIP 60452 |
26.86 |
| 2026-10-02 12:00 |
12:23:51.18 |
-17:09:42.3 |
HIP 60452 |
29.08 |
| 2026-10-03 00:00 |
12:24:10.65 |
-17:11:44.2 |
HIP 60653 |
24.96 |
| 2026-10-03 12:00 |
12:24:30.13 |
-17:13:46.4 |
HIP 60653 |
20.13 |
| 2026-10-04 00:00 |
12:24:49.63 |
-17:15:49.1 |
HIP 60653 |
15.47 |
| 2026-10-04 12:00 |
12:25:09.13 |
-17:17:52.2 |
HIP 60653 |
11.19 |
| 2026-10-05 00:00 |
12:25:28.64 |
-17:19:55.7 |
HIP 60653 |
7.93 |
| 2026-10-05 12:00 |
12:25:48.17 |
-17:21:59.6 |
HIP 60653 |
7.25 |
| 2026-10-06 00:00 |
12:26:07.70 |
-17:24:03.9 |
HIP 60653 |
9.71 |
| 2026-10-06 12:00 |
12:26:27.23 |
-17:26:08.6 |
HIP 60653 |
13.72 |
| 2026-10-07 00:00 |
12:26:46.78 |
-17:28:13.7 |
HIP 60653 |
18.29 |
| 2026-10-07 12:00 |
12:27:06.33 |
-17:30:19.2 |
HIP 60653 |
23.09 |
| 2026-10-08 00:00 |
12:27:25.89 |
-17:32:25.1 |
HIP 60653 |
28.00 |
| 2026-10-08 12:00 |
12:27:45.45 |
-17:34:31.3 |
HIP 60653 |
32.98 |
| 2026-10-09 00:00 |
12:28:05.01 |
-17:36:38.0 |
HIP 60663 |
35.49 |
| 2026-10-09 12:00 |
12:28:24.58 |
-17:38:45.0 |
HIP 61005 |
31.01 |
| 2026-10-10 00:00 |
12:28:44.16 |
-17:40:52.4 |
HIP 61005 |
25.99 |
| 2026-10-10 12:00 |
12:29:03.73 |
-17:43:00.1 |
HIP 61005 |
21.01 |
| 2026-10-11 00:00 |
12:29:23.31 |
-17:45:08.2 |
HIP 61005 |
16.12 |
| 2026-10-11 12:00 |
12:29:42.88 |
-17:47:16.7 |
HIP 61005 |
11.44 |
| 2026-10-12 00:00 |
12:30:02.46 |
-17:49:25.5 |
HIP 61005 |
7.37 |
| 2026-10-12 12:00 |
12:30:22.04 |
-17:51:34.7 |
HIP 61005 |
5.51 |
| 2026-10-13 00:00 |
12:30:41.62 |
-17:53:44.2 |
HIP 61005 |
7.68 |
| 2026-10-13 12:00 |
12:31:01.19 |
-17:55:54.1 |
HIP 61005 |
11.84 |
| 2026-10-14 00:00 |
12:31:20.76 |
-17:58:04.3 |
HIP 61005 |
16.56 |
| 2026-10-14 12:00 |
12:31:40.33 |
-18:00:14.8 |
HIP 61005 |
21.47 |
| 2026-10-15 00:00 |
12:31:59.90 |
-18:02:25.7 |
HIP 61005 |
26.46 |
| 2026-10-15 12:00 |
12:32:19.46 |
-18:04:36.8 |
HIP 61308 |
25.31 |
| 2026-10-16 00:00 |
12:32:39.02 |
-18:06:48.3 |
HIP 61345 |
22.05 |