| 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 |
-0.623 |
| 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) |
| 2026-07-29 00:00 |
15:09:17.90 |
-22:39:46.0 |
HIP 74219 |
10.37 |
| 2026-07-29 12:00 |
15:09:19.20 |
-22:39:37.0 |
HIP 74219 |
10.14 |
| 2026-07-30 00:00 |
15:09:20.64 |
-22:39:28.5 |
HIP 74219 |
9.88 |
| 2026-07-30 12:00 |
15:09:22.20 |
-22:39:20.5 |
HIP 74219 |
9.60 |
| 2026-07-31 00:00 |
15:09:23.90 |
-22:39:13.0 |
HIP 74219 |
9.30 |
| 2026-07-31 12:00 |
15:09:25.73 |
-22:39:06.0 |
HIP 74219 |
8.98 |
| 2026-08-01 00:00 |
15:09:27.69 |
-22:38:59.4 |
HIP 74219 |
8.63 |
| 2026-08-01 12:00 |
15:09:29.78 |
-22:38:53.4 |
HIP 74219 |
8.27 |
| 2026-08-02 00:00 |
15:09:32.01 |
-22:38:47.8 |
HIP 74219 |
7.89 |
| 2026-08-02 12:00 |
15:09:34.36 |
-22:38:42.8 |
HIP 74219 |
7.50 |
| 2026-08-03 00:00 |
15:09:36.84 |
-22:38:38.3 |
HIP 74219 |
7.10 |
| 2026-08-03 12:00 |
15:09:39.46 |
-22:38:34.2 |
HIP 74219 |
6.70 |
| 2026-08-04 00:00 |
15:09:42.20 |
-22:38:30.7 |
HIP 74219 |
6.30 |
| 2026-08-04 12:00 |
15:09:45.07 |
-22:38:27.6 |
HIP 74219 |
5.93 |
| 2026-08-05 00:00 |
15:09:48.08 |
-22:38:25.1 |
HIP 74219 |
5.58 |
| 2026-08-05 12:00 |
15:09:51.21 |
-22:38:23.0 |
HIP 74219 |
5.29 |
| 2026-08-06 00:00 |
15:09:54.48 |
-22:38:21.5 |
HIP 74219 |
5.06 |
| 2026-08-06 12:00 |
15:09:57.87 |
-22:38:20.5 |
HIP 74219 |
4.93 |
| 2026-08-07 00:00 |
15:10:01.40 |
-22:38:19.9 |
HIP 74219 |
4.92 |
| 2026-08-07 12:00 |
15:10:05.05 |
-22:38:19.9 |
HIP 74219 |
5.03 |
| 2026-08-08 00:00 |
15:10:08.84 |
-22:38:20.4 |
HIP 74219 |
5.29 |
| 2026-08-08 12:00 |
15:10:12.75 |
-22:38:21.3 |
HIP 74219 |
5.67 |
| 2026-08-09 00:00 |
15:10:16.79 |
-22:38:22.8 |
HIP 74219 |
6.18 |
| 2026-08-09 12:00 |
15:10:20.96 |
-22:38:24.8 |
HIP 74219 |
6.79 |
| 2026-08-10 00:00 |
15:10:25.26 |
-22:38:27.3 |
HIP 74219 |
7.49 |
| 2026-08-10 12:00 |
15:10:29.69 |
-22:38:30.3 |
HIP 74219 |
8.28 |
| 2026-08-11 00:00 |
15:10:34.25 |
-22:38:33.8 |
HIP 74219 |
9.13 |
| 2026-08-11 12:00 |
15:10:38.93 |
-22:38:37.8 |
HIP 74219 |
10.04 |
| 2026-08-12 00:00 |
15:10:43.74 |
-22:38:42.3 |
HIP 74219 |
11.01 |
| 2026-08-12 12:00 |
15:10:48.68 |
-22:38:47.3 |
HIP 74219 |
12.02 |
| 2026-08-13 00:00 |
15:10:53.75 |
-22:38:52.8 |
HIP 74219 |
13.09 |
| 2026-08-13 12:00 |
15:10:58.95 |
-22:38:58.8 |
HIP 74219 |
14.19 |
| 2026-08-14 00:00 |
15:11:04.27 |
-22:39:05.3 |
HIP 74219 |
15.34 |
| 2026-08-14 12:00 |
15:11:09.72 |
-22:39:12.3 |
HIP 74219 |
16.52 |
| 2026-08-15 00:00 |
15:11:15.29 |
-22:39:19.8 |
HIP 74219 |
17.74 |
| 2026-08-15 12:00 |
15:11:20.99 |
-22:39:27.8 |
HIP 74219 |
19.00 |
| 2026-08-16 00:00 |
15:11:26.82 |
-22:39:36.3 |
HIP 74219 |
20.29 |
| 2026-08-16 12:00 |
15:11:32.77 |
-22:39:45.3 |
HIP 74219 |
21.62 |
| 2026-08-17 00:00 |
15:11:38.84 |
-22:39:54.8 |
HIP 74219 |
22.98 |
| 2026-08-17 12:00 |
15:11:45.04 |
-22:40:04.8 |
HIP 74219 |
24.37 |
| 2026-08-18 00:00 |
15:11:51.37 |
-22:40:15.2 |
HIP 74219 |
25.80 |
| 2026-08-18 12:00 |
15:11:57.81 |
-22:40:26.2 |
HIP 74219 |
27.26 |
| 2026-08-19 00:00 |
15:12:04.38 |
-22:40:37.7 |
HIP 74219 |
28.75 |