P/2013 J2 (McNaught)
| 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
$$
M_a = (12.546 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.546 |
| n |
2.000 |
| gf |
0.999 |
| gb |
-0.765 |
| 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) |
| 2026-02-03 00:00 |
12:09:55.94 |
-18:46:52.6 |
HIP 59195 |
25.43 |
| 2026-02-03 12:00 |
12:09:49.31 |
-18:47:20.6 |
HIP 59195 |
24.29 |
| 2026-02-04 00:00 |
12:09:42.55 |
-18:47:47.5 |
HIP 59195 |
23.17 |
| 2026-02-04 12:00 |
12:09:35.66 |
-18:48:13.4 |
HIP 59195 |
22.10 |
| 2026-02-05 00:00 |
12:09:28.65 |
-18:48:38.3 |
HIP 59195 |
21.06 |
| 2026-02-05 12:00 |
12:09:21.52 |
-18:49:02.0 |
HIP 59195 |
20.09 |
| 2026-02-06 00:00 |
12:09:14.25 |
-18:49:24.7 |
HIP 59195 |
19.19 |
| 2026-02-06 12:00 |
12:09:06.87 |
-18:49:46.4 |
HIP 59195 |
18.39 |
| 2026-02-07 00:00 |
12:08:59.36 |
-18:50:07.0 |
HIP 59195 |
17.70 |
| 2026-02-07 12:00 |
12:08:51.73 |
-18:50:26.4 |
HIP 59195 |
17.14 |
| 2026-02-08 00:00 |
12:08:43.97 |
-18:50:44.9 |
HIP 59195 |
16.74 |
| 2026-02-08 12:00 |
12:08:36.10 |
-18:51:02.2 |
HIP 59195 |
16.52 |
| 2026-02-09 00:00 |
12:08:28.10 |
-18:51:18.4 |
HIP 59195 |
16.50 |
| 2026-02-09 12:00 |
12:08:19.99 |
-18:51:33.5 |
HIP 59195 |
16.67 |
| 2026-02-10 00:00 |
12:08:11.75 |
-18:51:47.6 |
HIP 59195 |
17.05 |
| 2026-02-10 12:00 |
12:08:03.40 |
-18:52:00.5 |
HIP 59195 |
17.63 |
| 2026-02-11 00:00 |
12:07:54.92 |
-18:52:12.3 |
HIP 59195 |
18.40 |
| 2026-02-11 12:00 |
12:07:46.33 |
-18:52:23.0 |
HIP 59195 |
19.35 |
| 2026-02-12 00:00 |
12:07:37.63 |
-18:52:32.6 |
HIP 59195 |
20.45 |
| 2026-02-12 12:00 |
12:07:28.81 |
-18:52:41.1 |
HIP 59195 |
21.70 |
| 2026-02-13 00:00 |
12:07:19.87 |
-18:52:48.5 |
HIP 59000 |
21.10 |
| 2026-02-13 12:00 |
12:07:10.82 |
-18:52:54.7 |
HIP 59000 |
18.97 |
| 2026-02-14 00:00 |
12:07:01.66 |
-18:52:59.8 |
HIP 59000 |
16.80 |
| 2026-02-14 12:00 |
12:06:52.39 |
-18:53:03.8 |
HIP 59000 |
14.61 |
| 2026-02-15 00:00 |
12:06:43.00 |
-18:53:06.7 |
HIP 59000 |
12.40 |
| 2026-02-15 12:00 |
12:06:33.51 |
-18:53:08.4 |
HIP 59000 |
10.16 |
| 2026-02-16 00:00 |
12:06:23.90 |
-18:53:09.0 |
HIP 59000 |
7.89 |
| 2026-02-16 12:00 |
12:06:14.19 |
-18:53:08.4 |
HIP 59000 |
5.60 |
| 2026-02-17 00:00 |
12:06:04.37 |
-18:53:06.7 |
HIP 59000 |
3.31 |
| 2026-02-17 12:00 |
12:05:54.45 |
-18:53:03.9 |
HIP 59000 |
1.08 |
| 2026-02-18 00:00 |
12:05:44.42 |
-18:53:00.0 |
HIP 59000 |
1.57 |
| 2026-02-18 12:00 |
12:05:34.29 |
-18:52:54.8 |
HIP 59000 |
3.90 |
| 2026-02-19 00:00 |
12:05:24.06 |
-18:52:48.5 |
HIP 59000 |
6.30 |
| 2026-02-19 12:00 |
12:05:13.73 |
-18:52:41.1 |
HIP 59000 |
8.74 |
| 2026-02-20 00:00 |
12:05:03.30 |
-18:52:32.6 |
HIP 59000 |
11.21 |
| 2026-02-20 12:00 |
12:04:52.77 |
-18:52:22.9 |
HIP 59000 |
13.70 |
| 2026-02-21 00:00 |
12:04:42.14 |
-18:52:12.1 |
HIP 59000 |
16.21 |
| 2026-02-21 12:00 |
12:04:31.42 |
-18:52:00.1 |
HIP 59000 |
18.75 |
| 2026-02-22 00:00 |
12:04:20.61 |
-18:51:47.0 |
HIP 59000 |
21.32 |
| 2026-02-22 12:00 |
12:04:09.70 |
-18:51:32.7 |
HIP 59000 |
23.90 |
| 2026-02-23 00:00 |
12:03:58.70 |
-18:51:17.3 |
HIP 59000 |
26.52 |
| 2026-02-23 12:00 |
12:03:47.61 |
-18:51:00.7 |
HIP 59000 |
29.15 |
| 2026-02-24 00:00 |
12:03:36.43 |
-18:50:43.1 |
HIP 59000 |
31.81 |