| Parameter |
Value |
| Designation |
P/2011 P1 (McNaught) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2010-07-24T04:00:53.856000Z |
| Orbit solution date (soln_date, UTC) |
2022-03-08T19:43:47Z |
| Obs used |
156 |
| NEO |
- |
| M1 |
6.800 |
| K1 |
11.500 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2011-08-20.0000000 |
| e |
0.36688593 |
| q (au) |
4.952165 |
| a (au) |
7.821915 |
| i (deg) |
6.308803 |
| Ω (om, deg) |
10.081774 |
| ω (w, deg) |
342.119808 |
| M (ma, deg) |
17.653674 |
Magnitude
Scatter + Global Linear
$$
M_a = (3.503 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
3.503 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.500 |
| 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) |
| 2026-03-26 00:00 |
15:43:00.01 |
-24:28:34.1 |
HIP 76969 |
12.65 |
| 2026-03-26 12:00 |
15:42:55.44 |
-24:28:40.8 |
HIP 76969 |
12.80 |
| 2026-03-27 00:00 |
15:42:50.74 |
-24:28:47.1 |
HIP 76969 |
13.02 |
| 2026-03-27 12:00 |
15:42:45.92 |
-24:28:52.9 |
HIP 76969 |
13.33 |
| 2026-03-28 00:00 |
15:42:40.96 |
-24:28:58.2 |
HIP 76969 |
13.72 |
| 2026-03-28 12:00 |
15:42:35.89 |
-24:29:03.1 |
HIP 76969 |
14.20 |
| 2026-03-29 00:00 |
15:42:30.68 |
-24:29:07.5 |
HIP 76969 |
14.75 |
| 2026-03-29 12:00 |
15:42:25.36 |
-24:29:11.4 |
HIP 76969 |
15.39 |
| 2026-03-30 00:00 |
15:42:19.91 |
-24:29:14.9 |
HIP 76834 |
15.54 |
| 2026-03-30 12:00 |
15:42:14.33 |
-24:29:17.9 |
HIP 76834 |
14.38 |
| 2026-03-31 00:00 |
15:42:08.64 |
-24:29:20.4 |
HIP 76834 |
13.20 |
| 2026-03-31 12:00 |
15:42:02.82 |
-24:29:22.4 |
HIP 76834 |
12.02 |
| 2026-04-01 00:00 |
15:41:56.88 |
-24:29:24.0 |
HIP 76834 |
10.85 |
| 2026-04-01 12:00 |
15:41:50.82 |
-24:29:25.1 |
HIP 76834 |
9.69 |
| 2026-04-02 00:00 |
15:41:44.64 |
-24:29:25.7 |
HIP 76834 |
8.58 |
| 2026-04-02 12:00 |
15:41:38.34 |
-24:29:25.8 |
HIP 76834 |
7.53 |
| 2026-04-03 00:00 |
15:41:31.92 |
-24:29:25.5 |
HIP 76834 |
6.62 |
| 2026-04-03 12:00 |
15:41:25.38 |
-24:29:24.7 |
HIP 76834 |
5.91 |
| 2026-04-04 00:00 |
15:41:18.73 |
-24:29:23.4 |
HIP 76834 |
5.51 |
| 2026-04-04 12:00 |
15:41:11.96 |
-24:29:21.6 |
HIP 76834 |
5.50 |
| 2026-04-05 00:00 |
15:41:05.08 |
-24:29:19.3 |
HIP 76834 |
5.92 |
| 2026-04-05 12:00 |
15:40:58.08 |
-24:29:16.6 |
HIP 76834 |
6.69 |
| 2026-04-06 00:00 |
15:40:50.96 |
-24:29:13.4 |
HIP 76834 |
7.74 |
| 2026-04-06 12:00 |
15:40:43.73 |
-24:29:09.7 |
HIP 76834 |
8.97 |
| 2026-04-07 00:00 |
15:40:36.39 |
-24:29:05.5 |
HIP 76834 |
10.34 |
| 2026-04-07 12:00 |
15:40:28.94 |
-24:29:00.9 |
HIP 76834 |
11.81 |
| 2026-04-08 00:00 |
15:40:21.38 |
-24:28:55.7 |
HIP 76812 |
13.01 |
| 2026-04-08 12:00 |
15:40:13.70 |
-24:28:50.1 |
HIP 76812 |
14.19 |
| 2026-04-09 00:00 |
15:40:05.92 |
-24:28:44.0 |
HIP 76812 |
15.49 |
| 2026-04-09 12:00 |
15:39:58.03 |
-24:28:37.4 |
HIP 76812 |
16.89 |
| 2026-04-10 00:00 |
15:39:50.03 |
-24:28:30.3 |
HIP 76812 |
18.38 |
| 2026-04-10 12:00 |
15:39:41.93 |
-24:28:22.8 |
HIP 76812 |
19.94 |
| 2026-04-11 00:00 |
15:39:33.71 |
-24:28:14.8 |
HIP 76578 |
19.67 |
| 2026-04-11 12:00 |
15:39:25.40 |
-24:28:06.3 |
HIP 76578 |
18.23 |
| 2026-04-12 00:00 |
15:39:16.98 |
-24:27:57.3 |
HIP 76578 |
16.86 |
| 2026-04-12 12:00 |
15:39:08.46 |
-24:27:47.8 |
HIP 76578 |
15.59 |
| 2026-04-13 00:00 |
15:38:59.84 |
-24:27:37.9 |
HIP 76578 |
14.48 |
| 2026-04-13 12:00 |
15:38:51.11 |
-24:27:27.4 |
HIP 76578 |
13.55 |
| 2026-04-14 00:00 |
15:38:42.29 |
-24:27:16.5 |
HIP 76578 |
12.86 |
| 2026-04-14 12:00 |
15:38:33.37 |
-24:27:05.2 |
HIP 76578 |
12.47 |
| 2026-04-15 00:00 |
15:38:24.35 |
-24:26:53.3 |
HIP 76578 |
12.42 |
| 2026-04-15 12:00 |
15:38:15.24 |
-24:26:41.0 |
HIP 76578 |
12.71 |
| 2026-04-16 00:00 |
15:38:06.03 |
-24:26:28.2 |
HIP 76578 |
13.34 |