| Parameter |
Value |
| Designation |
131P/Mueller 2 |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2012-01-06T09:01:53.875200Z |
| Orbit solution date (soln_date, UTC) |
2026-09-08T08:46:48Z |
| Obs used |
921 |
| NEO |
- |
| M1 |
8.500 |
| K1 |
24.250 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-09-24.0000000 |
| e |
0.34319115 |
| q (au) |
2.416305 |
| a (au) |
3.678856 |
| i (deg) |
7.355121 |
| Ω (om, deg) |
214.196943 |
| ω (w, deg) |
179.268423 |
| M (ma, deg) |
87.526941 |
Magnitude
Scatter + Global Linear
$$
M_a = (16.656 + 2.200\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
16.656 |
| n |
2.200 |
| gf |
0.955 |
| gb |
-0.857 |
| k |
0.997 |
| δ90 |
1.000 |
| 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) |
| 2026-09-20 00:00 |
07:33:21.33 |
+15:53:35.8 |
HIP 36760 |
5.41 |
| 2026-09-20 12:00 |
07:33:59.57 |
+15:50:59.5 |
HIP 36760 |
5.72 |
| 2026-09-21 00:00 |
07:34:37.61 |
+15:48:22.8 |
HIP 36760 |
14.75 |
| 2026-09-21 12:00 |
07:35:15.45 |
+15:45:45.7 |
HIP 36760 |
24.11 |
| 2026-09-22 00:00 |
07:35:53.09 |
+15:43:08.3 |
HIP 37019 |
23.27 |
| 2026-09-22 12:00 |
07:36:30.53 |
+15:40:30.4 |
HIP 37019 |
24.05 |
| 2026-09-23 00:00 |
07:37:07.77 |
+15:37:52.2 |
HIP 37019 |
28.12 |
| 2026-09-23 12:00 |
07:37:44.81 |
+15:35:13.6 |
HIP 37019 |
34.29 |
| 2026-09-24 00:00 |
07:38:21.65 |
+15:32:34.7 |
HIP 37242 |
34.18 |
| 2026-09-24 12:00 |
07:38:58.28 |
+15:29:55.5 |
HIP 37242 |
35.87 |
| 2026-09-25 00:00 |
07:39:34.71 |
+15:27:16.0 |
HIP 37499 |
32.82 |
| 2026-09-25 12:00 |
07:40:10.93 |
+15:24:36.1 |
HIP 37499 |
25.40 |
| 2026-09-26 00:00 |
07:40:46.94 |
+15:21:55.9 |
HIP 37499 |
19.50 |
| 2026-09-26 12:00 |
07:41:22.75 |
+15:19:15.5 |
HIP 37499 |
16.77 |
| 2026-09-27 00:00 |
07:41:58.35 |
+15:16:34.7 |
HIP 37585 |
16.89 |
| 2026-09-27 12:00 |
07:42:33.74 |
+15:13:53.7 |
HIP 37585 |
10.11 |
| 2026-09-28 00:00 |
07:43:08.91 |
+15:11:12.5 |
HIP 37585 |
8.88 |
| 2026-09-28 12:00 |
07:43:43.88 |
+15:08:30.9 |
HIP 37685 |
7.33 |
| 2026-09-29 00:00 |
07:44:18.63 |
+15:05:49.2 |
HIP 37685 |
11.39 |
| 2026-09-29 12:00 |
07:44:53.17 |
+15:03:07.2 |
HIP 37685 |
18.97 |
| 2026-09-30 00:00 |
07:45:27.49 |
+15:00:25.0 |
HIP 37836 |
24.44 |
| 2026-09-30 12:00 |
07:46:01.59 |
+14:57:42.6 |
HIP 37836 |
23.50 |
| 2026-10-01 00:00 |
07:46:35.47 |
+14:55:00.0 |
HIP 37836 |
25.60 |
| 2026-10-01 12:00 |
07:47:09.13 |
+14:52:17.2 |
HIP 37836 |
30.08 |
| 2026-10-02 00:00 |
07:47:42.58 |
+14:49:34.2 |
HIP 38218 |
34.31 |
| 2026-10-02 12:00 |
07:48:15.79 |
+14:46:51.1 |
HIP 38218 |
29.34 |
| 2026-10-03 00:00 |
07:48:48.79 |
+14:44:07.8 |
HIP 38276 |
25.66 |
| 2026-10-03 12:00 |
07:49:21.55 |
+14:41:24.4 |
HIP 38276 |
19.23 |
| 2026-10-04 00:00 |
07:49:54.09 |
+14:38:40.9 |
HIP 38276 |
14.90 |
| 2026-10-04 12:00 |
07:50:26.40 |
+14:35:57.3 |
HIP 38276 |
14.60 |
| 2026-10-05 00:00 |
07:50:58.48 |
+14:33:13.5 |
HIP 38276 |
18.45 |
| 2026-10-05 12:00 |
07:51:30.33 |
+14:30:29.7 |
HIP 38360 |
20.32 |
| 2026-10-06 00:00 |
07:52:01.94 |
+14:27:45.8 |
HIP 38360 |
19.78 |
| 2026-10-06 12:00 |
07:52:33.32 |
+14:25:01.9 |
HIP 38360 |
22.35 |
| 2026-10-07 00:00 |
07:53:04.46 |
+14:22:17.9 |
HIP 38360 |
27.13 |
| 2026-10-07 12:00 |
07:53:35.37 |
+14:19:33.9 |
HIP 38360 |
33.13 |
| 2026-10-08 00:00 |
07:54:06.03 |
+14:16:49.8 |
HIP 38751 |
28.17 |
| 2026-10-08 12:00 |
07:54:36.45 |
+14:14:05.8 |
HIP 38751 |
21.49 |
| 2026-10-09 00:00 |
07:55:06.62 |
+14:11:21.8 |
HIP 38751 |
15.99 |
| 2026-10-09 12:00 |
07:55:36.56 |
+14:08:37.7 |
HIP 38751 |
13.10 |
| 2026-10-10 00:00 |
07:56:06.24 |
+14:05:53.8 |
HIP 38751 |
14.41 |
| 2026-10-10 12:00 |
07:56:35.68 |
+14:03:09.8 |
HIP 38819 |
17.43 |
| 2026-10-11 00:00 |
07:57:04.87 |
+14:00:26.0 |
HIP 38819 |
20.87 |