P/2011 P1 (McNaught)
| 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) |
| 2026-02-03 00:00 |
15:39:11.13 |
-23:40:00.0 |
HIP 76689 |
9.84 |
| 2026-02-03 12:00 |
15:39:19.72 |
-23:40:47.3 |
HIP 76689 |
8.15 |
| 2026-02-04 00:00 |
15:39:28.20 |
-23:41:34.2 |
HIP 76689 |
6.71 |
| 2026-02-04 12:00 |
15:39:36.56 |
-23:42:20.9 |
HIP 76689 |
5.70 |
| 2026-02-05 00:00 |
15:39:44.82 |
-23:43:07.3 |
HIP 76689 |
5.33 |
| 2026-02-05 12:00 |
15:39:52.96 |
-23:43:53.3 |
HIP 76689 |
5.70 |
| 2026-02-06 00:00 |
15:40:00.99 |
-23:44:39.0 |
HIP 76742 |
5.74 |
| 2026-02-06 12:00 |
15:40:08.91 |
-23:45:24.4 |
HIP 76742 |
4.11 |
| 2026-02-07 00:00 |
15:40:16.71 |
-23:46:09.5 |
HIP 76742 |
2.93 |
| 2026-02-07 12:00 |
15:40:24.40 |
-23:46:54.2 |
HIP 76742 |
2.77 |
| 2026-02-08 00:00 |
15:40:31.97 |
-23:47:38.6 |
HIP 76742 |
3.73 |
| 2026-02-08 12:00 |
15:40:39.42 |
-23:48:22.7 |
HIP 76742 |
5.20 |
| 2026-02-09 00:00 |
15:40:46.76 |
-23:49:06.4 |
HIP 76742 |
6.83 |
| 2026-02-09 12:00 |
15:40:53.98 |
-23:49:49.8 |
HIP 76742 |
8.51 |
| 2026-02-10 00:00 |
15:41:01.09 |
-23:50:32.9 |
HIP 76742 |
10.21 |
| 2026-02-10 12:00 |
15:41:08.07 |
-23:51:15.6 |
HIP 76742 |
11.90 |
| 2026-02-11 00:00 |
15:41:14.94 |
-23:51:58.0 |
HIP 76742 |
13.58 |
| 2026-02-11 12:00 |
15:41:21.69 |
-23:52:40.1 |
HIP 76742 |
15.24 |
| 2026-02-12 00:00 |
15:41:28.31 |
-23:53:21.8 |
HIP 76742 |
16.88 |
| 2026-02-12 12:00 |
15:41:34.82 |
-23:54:03.1 |
HIP 76742 |
18.49 |
| 2026-02-13 00:00 |
15:41:41.20 |
-23:54:44.1 |
HIP 76742 |
20.08 |
| 2026-02-13 12:00 |
15:41:47.46 |
-23:55:24.8 |
HIP 76742 |
21.65 |
| 2026-02-14 00:00 |
15:41:53.60 |
-23:56:05.1 |
HIP 76742 |
23.19 |
| 2026-02-14 12:00 |
15:41:59.62 |
-23:56:45.0 |
HIP 76969 |
23.54 |
| 2026-02-15 00:00 |
15:42:05.51 |
-23:57:24.6 |
HIP 76969 |
22.23 |
| 2026-02-15 12:00 |
15:42:11.28 |
-23:58:03.8 |
HIP 76969 |
20.97 |
| 2026-02-16 00:00 |
15:42:16.92 |
-23:58:42.7 |
HIP 76969 |
19.76 |
| 2026-02-16 12:00 |
15:42:22.44 |
-23:59:21.2 |
HIP 76969 |
18.60 |
| 2026-02-17 00:00 |
15:42:27.83 |
-23:59:59.4 |
HIP 76969 |
17.49 |
| 2026-02-17 12:00 |
15:42:33.10 |
-24:00:37.2 |
HIP 76969 |
16.44 |
| 2026-02-18 00:00 |
15:42:38.24 |
-24:01:14.6 |
HIP 76969 |
15.45 |
| 2026-02-18 12:00 |
15:42:43.25 |
-24:01:51.7 |
HIP 76969 |
14.53 |
| 2026-02-19 00:00 |
15:42:48.13 |
-24:02:28.4 |
HIP 76969 |
13.69 |
| 2026-02-19 12:00 |
15:42:52.89 |
-24:03:04.7 |
HIP 76969 |
12.92 |
| 2026-02-20 00:00 |
15:42:57.51 |
-24:03:40.7 |
HIP 76969 |
12.24 |
| 2026-02-20 12:00 |
15:43:02.01 |
-24:04:16.2 |
HIP 76969 |
11.66 |
| 2026-02-21 00:00 |
15:43:06.38 |
-24:04:51.5 |
HIP 76969 |
11.17 |
| 2026-02-21 12:00 |
15:43:10.62 |
-24:05:26.3 |
HIP 76969 |
10.78 |
| 2026-02-22 00:00 |
15:43:14.73 |
-24:06:00.7 |
HIP 76969 |
10.49 |
| 2026-02-22 12:00 |
15:43:18.71 |
-24:06:34.8 |
HIP 76969 |
10.31 |
| 2026-02-23 00:00 |
15:43:22.56 |
-24:07:08.5 |
HIP 76969 |
10.23 |
| 2026-02-23 12:00 |
15:43:26.28 |
-24:07:41.8 |
HIP 76969 |
10.24 |
| 2026-02-24 00:00 |
15:43:29.87 |
-24:08:14.8 |
HIP 76969 |
10.33 |