| Parameter |
Value |
| Designation |
191P/McNaught |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2007-09-13T14:40:41.669760Z |
| Orbit solution date (soln_date, UTC) |
2024-10-05T23:12:39Z |
| Obs used |
787 |
| NEO |
- |
| M1 |
13.800 |
| K1 |
8.250 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2010-02-25.0000000 |
| e |
0.42072245 |
| q (au) |
2.046442 |
| a (au) |
3.532749 |
| i (deg) |
8.759005 |
| Ω (om, deg) |
106.503897 |
| ω (w, deg) |
274.213416 |
| M (ma, deg) |
132.906520 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.851 + 4.652\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.851 |
| n |
4.652 |
| gf |
0.910 |
| gb |
-0.898 |
| k |
1.000 |
| δ90 |
6.023 |
| 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) |
| 2026-06-01 00:00 |
16:46:10.09 |
-17:04:58.8 |
HIP 82089 |
11.01 |
| 2026-06-01 12:00 |
16:45:47.80 |
-17:04:47.3 |
HIP 82089 |
11.54 |
| 2026-06-02 00:00 |
16:45:25.48 |
-17:04:36.0 |
HIP 82089 |
14.23 |
| 2026-06-02 12:00 |
16:45:03.13 |
-17:04:24.9 |
HIP 82089 |
18.14 |
| 2026-06-03 00:00 |
16:44:40.75 |
-17:04:14.1 |
HIP 82089 |
22.65 |
| 2026-06-03 12:00 |
16:44:18.35 |
-17:04:03.5 |
HIP 82089 |
27.47 |
| 2026-06-04 00:00 |
16:43:55.92 |
-17:03:53.2 |
HIP 81899 |
27.17 |
| 2026-06-04 12:00 |
16:43:33.48 |
-17:03:43.2 |
HIP 81899 |
27.28 |
| 2026-06-05 00:00 |
16:43:11.03 |
-17:03:33.4 |
HIP 81723 |
24.35 |
| 2026-06-05 12:00 |
16:42:48.57 |
-17:03:23.9 |
HIP 81723 |
19.25 |
| 2026-06-06 00:00 |
16:42:26.10 |
-17:03:14.7 |
HIP 81723 |
14.36 |
| 2026-06-06 12:00 |
16:42:03.63 |
-17:03:05.8 |
HIP 81723 |
9.99 |
| 2026-06-07 00:00 |
16:41:41.17 |
-17:02:57.1 |
HIP 81723 |
7.15 |
| 2026-06-07 12:00 |
16:41:18.72 |
-17:02:48.8 |
HIP 81723 |
7.75 |
| 2026-06-08 00:00 |
16:40:56.28 |
-17:02:40.8 |
HIP 81723 |
11.26 |
| 2026-06-08 12:00 |
16:40:33.86 |
-17:02:33.0 |
HIP 81723 |
15.85 |
| 2026-06-09 00:00 |
16:40:11.45 |
-17:02:25.6 |
HIP 81647 |
18.07 |
| 2026-06-09 12:00 |
16:39:49.08 |
-17:02:18.6 |
HIP 81647 |
20.97 |
| 2026-06-10 00:00 |
16:39:26.73 |
-17:02:11.8 |
HIP 81647 |
24.69 |
| 2026-06-10 12:00 |
16:39:04.41 |
-17:02:05.4 |
HIP 81409 |
23.63 |
| 2026-06-11 00:00 |
16:38:42.14 |
-17:01:59.4 |
HIP 81409 |
19.03 |
| 2026-06-11 12:00 |
16:38:19.90 |
-17:01:53.7 |
HIP 81409 |
14.94 |
| 2026-06-12 00:00 |
16:37:57.72 |
-17:01:48.3 |
HIP 81409 |
11.88 |
| 2026-06-12 12:00 |
16:37:35.58 |
-17:01:43.4 |
HIP 81409 |
10.74 |
| 2026-06-13 00:00 |
16:37:13.50 |
-17:01:38.8 |
HIP 81366 |
8.56 |
| 2026-06-13 12:00 |
16:36:51.48 |
-17:01:34.6 |
HIP 81366 |
8.29 |
| 2026-06-14 00:00 |
16:36:29.52 |
-17:01:30.7 |
HIP 81366 |
10.93 |
| 2026-06-14 12:00 |
16:36:07.64 |
-17:01:27.3 |
HIP 81366 |
14.98 |
| 2026-06-15 00:00 |
16:35:45.82 |
-17:01:24.3 |
HIP 81366 |
19.59 |
| 2026-06-15 12:00 |
16:35:24.08 |
-17:01:21.7 |
HIP 81366 |
24.42 |
| 2026-06-16 00:00 |
16:35:02.43 |
-17:01:19.5 |
HIP 81366 |
29.35 |
| 2026-06-16 12:00 |
16:34:40.86 |
-17:01:17.7 |
HIP 81366 |
34.33 |
| 2026-06-17 00:00 |
16:34:19.38 |
-17:01:16.3 |
HIP 81366 |
39.34 |
| 2026-06-17 12:00 |
16:33:57.99 |
-17:01:15.4 |
HIP 80998 |
42.94 |
| 2026-06-18 00:00 |
16:33:36.70 |
-17:01:14.9 |
HIP 80998 |
40.76 |
| 2026-06-18 12:00 |
16:33:15.52 |
-17:01:14.9 |
HIP 80894 |
39.05 |
| 2026-06-19 00:00 |
16:32:54.44 |
-17:01:15.3 |
HIP 80894 |
35.27 |
| 2026-06-19 12:00 |
16:32:33.47 |
-17:01:16.2 |
HIP 80894 |
31.86 |
| 2026-06-20 00:00 |
16:32:12.61 |
-17:01:17.5 |
HIP 80894 |
28.95 |
| 2026-06-20 12:00 |
16:31:51.88 |
-17:01:19.3 |
HIP 80894 |
26.68 |
| 2026-06-21 00:00 |
16:31:31.26 |
-17:01:21.6 |
HIP 80894 |
25.20 |
| 2026-06-21 12:00 |
16:31:10.77 |
-17:01:24.4 |
HIP 80894 |
24.65 |
| 2026-06-22 00:00 |
16:30:50.41 |
-17:01:27.6 |
HIP 80894 |
25.07 |