| Parameter |
Value |
| Designation |
P/2012 O2 (McNaught) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2012-06-25T02:23:11.711040Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:20Z |
| Obs used |
81 |
| NEO |
- |
| M1 |
17.300 |
| K1 |
10.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2012-07-31.0000000 |
| e |
0.53827101 |
| q (au) |
1.660834 |
| a (au) |
3.596989 |
| i (deg) |
24.527455 |
| Ω (om, deg) |
120.813582 |
| ω (w, deg) |
183.047391 |
| M (ma, deg) |
5.186765 |
Magnitude
Scatter + Global Linear
$$
M_a = (17.976 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
17.976 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.851 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
23:50:22.26 |
-10:26:33.9 |
HIP 117541 |
28.17 |
| 2026-05-12 12:00 |
23:51:39.28 |
-10:24:46.5 |
HIP 117541 |
33.56 |
| 2026-05-13 00:00 |
23:52:56.18 |
-10:23:00.2 |
HIP 117789 |
38.12 |
| 2026-05-13 12:00 |
23:54:12.96 |
-10:21:14.8 |
HIP 117964 |
33.51 |
| 2026-05-14 00:00 |
23:55:29.61 |
-10:19:30.6 |
HIP 117964 |
28.02 |
| 2026-05-14 12:00 |
23:56:46.14 |
-10:17:47.4 |
HIP 117964 |
34.07 |
| 2026-05-15 00:00 |
23:58:02.55 |
-10:16:05.3 |
HIP 33 |
36.64 |
| 2026-05-15 12:00 |
23:59:18.83 |
-10:14:24.4 |
HIP 33 |
20.82 |
| 2026-05-16 00:00 |
00:00:34.98 |
-10:12:44.6 |
HIP 33 |
15.25 |
| 2026-05-16 12:00 |
00:01:51.01 |
-10:11:06.0 |
HIP 33 |
27.15 |
| 2026-05-17 00:00 |
00:03:06.90 |
-10:09:28.6 |
HIP 329 |
16.13 |
| 2026-05-17 12:00 |
00:04:22.66 |
-10:07:52.4 |
HIP 329 |
2.61 |
| 2026-05-18 00:00 |
00:05:38.29 |
-10:06:17.4 |
HIP 329 |
21.27 |
| 2026-05-18 12:00 |
00:06:53.79 |
-10:04:43.7 |
HIP 462 |
34.37 |
| 2026-05-19 00:00 |
00:08:09.15 |
-10:03:11.3 |
HIP 771 |
21.57 |
| 2026-05-19 12:00 |
00:09:24.37 |
-10:01:40.1 |
HIP 771 |
9.70 |
| 2026-05-20 00:00 |
00:10:39.46 |
-10:00:10.3 |
HIP 771 |
20.29 |
| 2026-05-20 12:00 |
00:11:54.41 |
-09:58:41.8 |
HIP 947 |
16.87 |
| 2026-05-21 00:00 |
00:13:09.22 |
-09:57:14.7 |
HIP 1117 |
17.14 |
| 2026-05-21 12:00 |
00:14:23.90 |
-09:55:48.9 |
HIP 1117 |
13.20 |
| 2026-05-22 00:00 |
00:15:38.43 |
-09:54:24.5 |
HIP 1191 |
22.95 |
| 2026-05-22 12:00 |
00:16:52.82 |
-09:53:01.5 |
HIP 1274 |
27.55 |
| 2026-05-23 00:00 |
00:18:07.06 |
-09:51:39.9 |
HIP 1532 |
15.68 |
| 2026-05-23 12:00 |
00:19:21.17 |
-09:50:19.8 |
HIP 1532 |
8.44 |
| 2026-05-24 00:00 |
00:20:35.13 |
-09:49:01.0 |
HIP 1532 |
23.75 |
| 2026-05-24 12:00 |
00:21:48.94 |
-09:47:43.8 |
HIP 1787 |
16.91 |
| 2026-05-25 00:00 |
00:23:02.61 |
-09:46:28.0 |
HIP 1787 |
10.29 |
| 2026-05-25 12:00 |
00:24:16.13 |
-09:45:13.7 |
HIP 1787 |
24.22 |
| 2026-05-26 00:00 |
00:25:29.50 |
-09:44:01.0 |
HIP 2042 |
12.14 |
| 2026-05-26 12:00 |
00:26:42.73 |
-09:42:49.7 |
HIP 2140 |
11.26 |
| 2026-05-27 00:00 |
00:27:55.80 |
-09:41:40.0 |
HIP 2140 |
16.11 |
| 2026-05-27 12:00 |
00:29:08.73 |
-09:40:31.9 |
HIP 2250 |
17.85 |
| 2026-05-28 00:00 |
00:30:21.50 |
-09:39:25.3 |
HIP 2408 |
15.69 |
| 2026-05-28 12:00 |
00:31:34.12 |
-09:38:20.3 |
HIP 2408 |
19.13 |
| 2026-05-29 00:00 |
00:32:46.59 |
-09:37:17.0 |
HIP 2608 |
22.59 |
| 2026-05-29 12:00 |
00:33:58.90 |
-09:36:15.2 |
HIP 2608 |
26.28 |
| 2026-05-30 00:00 |
00:35:11.06 |
-09:35:15.1 |
HIP 2839 |
12.87 |
| 2026-05-30 12:00 |
00:36:23.06 |
-09:34:16.7 |
HIP 2839 |
6.61 |
| 2026-05-31 00:00 |
00:37:34.90 |
-09:33:20.0 |
HIP 2839 |
23.50 |
| 2026-05-31 12:00 |
00:38:46.59 |
-09:32:24.9 |
HIP 2961 |
32.77 |
| 2026-06-01 00:00 |
00:39:58.12 |
-09:31:31.5 |
HIP 3216 |
29.47 |
| 2026-06-01 12:00 |
00:41:09.48 |
-09:30:39.9 |
HIP 3216 |
27.21 |
| 2026-06-02 00:00 |
00:42:20.69 |
-09:29:50.0 |
HIP 3406 |
18.80 |