| Parameter |
Value |
| Designation |
C/1991 X2 (Mueller) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
1992-03-21T04:48:32.227200Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:29:41Z |
| Obs used |
149 |
| NEO |
- |
| M1 |
12.100 |
| K1 |
16.750 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
1992-01-30.0000000 |
| e |
1.00020139 |
| q (au) |
0.198797 |
| a (au) |
-987.134248 |
| i (deg) |
95.574370 |
| Ω (om, deg) |
288.783115 |
| ω (w, deg) |
306.985362 |
| M (ma, deg) |
-0.001627 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.627 + 5.215\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.627 |
| n |
5.215 |
| 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) |
| 2026-05-12 00:00 |
10:40:14.31 |
+75:48:28.2 |
HIP 51808 |
19.82 |
| 2026-05-12 12:00 |
10:40:11.95 |
+75:48:03.4 |
HIP 51808 |
19.57 |
| 2026-05-13 00:00 |
10:40:09.66 |
+75:47:38.4 |
HIP 51808 |
19.33 |
| 2026-05-13 12:00 |
10:40:07.44 |
+75:47:13.4 |
HIP 51808 |
19.10 |
| 2026-05-14 00:00 |
10:40:05.28 |
+75:46:48.2 |
HIP 51808 |
18.88 |
| 2026-05-14 12:00 |
10:40:03.18 |
+75:46:23.0 |
HIP 51808 |
18.67 |
| 2026-05-15 00:00 |
10:40:01.15 |
+75:45:57.6 |
HIP 51808 |
18.48 |
| 2026-05-15 12:00 |
10:39:59.17 |
+75:45:32.2 |
HIP 51808 |
18.29 |
| 2026-05-16 00:00 |
10:39:57.27 |
+75:45:06.7 |
HIP 51808 |
18.12 |
| 2026-05-16 12:00 |
10:39:55.42 |
+75:44:41.1 |
HIP 51808 |
17.96 |
| 2026-05-17 00:00 |
10:39:53.65 |
+75:44:15.4 |
HIP 51808 |
17.82 |
| 2026-05-17 12:00 |
10:39:51.93 |
+75:43:49.6 |
HIP 51808 |
17.69 |
| 2026-05-18 00:00 |
10:39:50.28 |
+75:43:23.8 |
HIP 51808 |
17.57 |
| 2026-05-18 12:00 |
10:39:48.69 |
+75:42:57.8 |
HIP 51808 |
17.46 |
| 2026-05-19 00:00 |
10:39:47.17 |
+75:42:31.8 |
HIP 51808 |
17.38 |
| 2026-05-19 12:00 |
10:39:45.71 |
+75:42:05.8 |
HIP 51808 |
17.30 |
| 2026-05-20 00:00 |
10:39:44.31 |
+75:41:39.6 |
HIP 51808 |
17.24 |
| 2026-05-20 12:00 |
10:39:42.98 |
+75:41:13.4 |
HIP 51808 |
17.20 |
| 2026-05-21 00:00 |
10:39:41.71 |
+75:40:47.1 |
HIP 51808 |
17.17 |
| 2026-05-21 12:00 |
10:39:40.50 |
+75:40:20.7 |
HIP 51808 |
17.16 |
| 2026-05-22 00:00 |
10:39:39.36 |
+75:39:54.3 |
HIP 51808 |
17.16 |
| 2026-05-22 12:00 |
10:39:38.28 |
+75:39:27.9 |
HIP 51808 |
17.18 |
| 2026-05-23 00:00 |
10:39:37.27 |
+75:39:01.3 |
HIP 51808 |
17.21 |
| 2026-05-23 12:00 |
10:39:36.32 |
+75:38:34.7 |
HIP 51808 |
17.26 |
| 2026-05-24 00:00 |
10:39:35.43 |
+75:38:08.1 |
HIP 51808 |
17.33 |
| 2026-05-24 12:00 |
10:39:34.60 |
+75:37:41.4 |
HIP 51808 |
17.41 |
| 2026-05-25 00:00 |
10:39:33.84 |
+75:37:14.6 |
HIP 51808 |
17.50 |
| 2026-05-25 12:00 |
10:39:33.14 |
+75:36:47.8 |
HIP 51808 |
17.61 |
| 2026-05-26 00:00 |
10:39:32.50 |
+75:36:21.0 |
HIP 51808 |
17.73 |
| 2026-05-26 12:00 |
10:39:31.93 |
+75:35:54.1 |
HIP 51808 |
17.87 |
| 2026-05-27 00:00 |
10:39:31.41 |
+75:35:27.1 |
HIP 51808 |
18.02 |
| 2026-05-27 12:00 |
10:39:30.96 |
+75:35:00.1 |
HIP 51808 |
18.19 |
| 2026-05-28 00:00 |
10:39:30.58 |
+75:34:33.1 |
HIP 51808 |
18.37 |
| 2026-05-28 12:00 |
10:39:30.25 |
+75:34:06.1 |
HIP 51808 |
18.56 |
| 2026-05-29 00:00 |
10:39:29.98 |
+75:33:39.0 |
HIP 51808 |
18.77 |
| 2026-05-29 12:00 |
10:39:29.78 |
+75:33:11.8 |
HIP 51808 |
18.98 |
| 2026-05-30 00:00 |
10:39:29.64 |
+75:32:44.7 |
HIP 51808 |
19.21 |
| 2026-05-30 12:00 |
10:39:29.56 |
+75:32:17.5 |
HIP 51808 |
19.45 |
| 2026-05-31 00:00 |
10:39:29.54 |
+75:31:50.2 |
HIP 51808 |
19.70 |
| 2026-05-31 12:00 |
10:39:29.59 |
+75:31:23.0 |
HIP 51808 |
19.96 |
| 2026-06-01 00:00 |
10:39:29.69 |
+75:30:55.7 |
HIP 51808 |
20.24 |
| 2026-06-01 12:00 |
10:39:29.86 |
+75:30:28.4 |
HIP 51808 |
20.52 |
| 2026-06-02 00:00 |
10:39:30.08 |
+75:30:01.1 |
HIP 51808 |
20.81 |