| Parameter |
Value |
| Designation |
C/2010 J2 (McNaught) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2010-06-03T20:45:36.622080Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:44Z |
| Obs used |
543 |
| NEO |
- |
| M1 |
10.100 |
| K1 |
9.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2010-08-16.0000000 |
| e |
0.99945919 |
| q (au) |
3.386996 |
| a (au) |
6262.872230 |
| i (deg) |
125.851540 |
| Ω (om, deg) |
311.794846 |
| ω (w, deg) |
4.616553 |
| M (ma, deg) |
0.000145 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.082 + 2.443\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.082 |
| n |
2.443 |
| gf |
0.993 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
9.955 |
| 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 |
11:02:58.89 |
+33:37:42.9 |
HIP 53799 |
31.92 |
| 2026-09-20 12:00 |
11:03:02.34 |
+33:37:29.7 |
HIP 53799 |
32.62 |
| 2026-09-21 00:00 |
11:03:05.77 |
+33:37:16.6 |
HIP 53799 |
33.32 |
| 2026-09-21 12:00 |
11:03:09.20 |
+33:37:03.8 |
HIP 53799 |
34.02 |
| 2026-09-22 00:00 |
11:03:12.62 |
+33:36:51.3 |
HIP 53799 |
34.72 |
| 2026-09-22 12:00 |
11:03:16.03 |
+33:36:38.9 |
HIP 53799 |
35.42 |
| 2026-09-23 00:00 |
11:03:19.44 |
+33:36:26.8 |
HIP 53799 |
36.12 |
| 2026-09-23 12:00 |
11:03:22.83 |
+33:36:14.9 |
HIP 53799 |
36.82 |
| 2026-09-24 00:00 |
11:03:26.22 |
+33:36:03.3 |
HIP 53799 |
37.52 |
| 2026-09-24 12:00 |
11:03:29.60 |
+33:35:51.8 |
HIP 54086 |
38.16 |
| 2026-09-25 00:00 |
11:03:32.97 |
+33:35:40.7 |
HIP 54134 |
37.92 |
| 2026-09-25 12:00 |
11:03:36.32 |
+33:35:29.7 |
HIP 54134 |
37.53 |
| 2026-09-26 00:00 |
11:03:39.67 |
+33:35:19.0 |
HIP 54134 |
37.15 |
| 2026-09-26 12:00 |
11:03:43.01 |
+33:35:08.5 |
HIP 54134 |
36.79 |
| 2026-09-27 00:00 |
11:03:46.34 |
+33:34:58.3 |
HIP 54134 |
36.44 |
| 2026-09-27 12:00 |
11:03:49.66 |
+33:34:48.3 |
HIP 54134 |
36.11 |
| 2026-09-28 00:00 |
11:03:52.97 |
+33:34:38.5 |
HIP 54134 |
35.79 |
| 2026-09-28 12:00 |
11:03:56.26 |
+33:34:29.0 |
HIP 54134 |
35.49 |
| 2026-09-29 00:00 |
11:03:59.55 |
+33:34:19.7 |
HIP 54134 |
35.20 |
| 2026-09-29 12:00 |
11:04:02.82 |
+33:34:10.7 |
HIP 54134 |
34.93 |
| 2026-09-30 00:00 |
11:04:06.09 |
+33:34:01.9 |
HIP 54134 |
34.68 |
| 2026-09-30 12:00 |
11:04:09.34 |
+33:33:53.3 |
HIP 54134 |
34.44 |
| 2026-10-01 00:00 |
11:04:12.57 |
+33:33:45.0 |
HIP 54134 |
34.22 |
| 2026-10-01 12:00 |
11:04:15.80 |
+33:33:36.9 |
HIP 54134 |
34.02 |
| 2026-10-02 00:00 |
11:04:19.02 |
+33:33:29.1 |
HIP 54134 |
33.84 |
| 2026-10-02 12:00 |
11:04:22.22 |
+33:33:21.5 |
HIP 54134 |
33.67 |
| 2026-10-03 00:00 |
11:04:25.40 |
+33:33:14.2 |
HIP 54134 |
33.52 |
| 2026-10-03 12:00 |
11:04:28.58 |
+33:33:07.1 |
HIP 54134 |
33.38 |
| 2026-10-04 00:00 |
11:04:31.74 |
+33:33:00.3 |
HIP 54134 |
33.27 |
| 2026-10-04 12:00 |
11:04:34.89 |
+33:32:53.7 |
HIP 54134 |
33.17 |
| 2026-10-05 00:00 |
11:04:38.02 |
+33:32:47.3 |
HIP 54134 |
33.08 |
| 2026-10-05 12:00 |
11:04:41.14 |
+33:32:41.2 |
HIP 54134 |
33.02 |
| 2026-10-06 00:00 |
11:04:44.25 |
+33:32:35.4 |
HIP 54134 |
32.97 |
| 2026-10-06 12:00 |
11:04:47.34 |
+33:32:29.8 |
HIP 54134 |
32.94 |
| 2026-10-07 00:00 |
11:04:50.41 |
+33:32:24.5 |
HIP 54134 |
32.92 |
| 2026-10-07 12:00 |
11:04:53.47 |
+33:32:19.4 |
HIP 54134 |
32.92 |
| 2026-10-08 00:00 |
11:04:56.51 |
+33:32:14.6 |
HIP 54134 |
32.94 |
| 2026-10-08 12:00 |
11:04:59.54 |
+33:32:10.0 |
HIP 54134 |
32.98 |
| 2026-10-09 00:00 |
11:05:02.55 |
+33:32:05.7 |
HIP 54134 |
33.03 |
| 2026-10-09 12:00 |
11:05:05.55 |
+33:32:01.6 |
HIP 54134 |
33.09 |
| 2026-10-10 00:00 |
11:05:08.53 |
+33:31:57.8 |
HIP 54134 |
33.17 |
| 2026-10-10 12:00 |
11:05:11.49 |
+33:31:54.3 |
HIP 54134 |
33.27 |
| 2026-10-11 00:00 |
11:05:14.44 |
+33:31:51.0 |
HIP 54134 |
33.38 |