| Parameter |
Value |
| Designation |
C/2009 UG89 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2010-12-16T06:17:33.682560Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:37Z |
| Obs used |
966 |
| NEO |
- |
| M1 |
5.200 |
| K1 |
15.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2010-10-30.0000000 |
| e |
1.00795978 |
| q (au) |
3.931171 |
| a (au) |
-493.879168 |
| i (deg) |
130.099828 |
| Ω (om, deg) |
321.007061 |
| ω (w, deg) |
60.651338 |
| M (ma, deg) |
-0.004244 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.767 + 2.529\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.767 |
| n |
2.529 |
| gf |
0.917 |
| gb |
-1.000 |
| k |
0.994 |
| δ90 |
9.999 |
| 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) |
| 2026-03-26 00:00 |
08:23:41.40 |
+04:30:40.0 |
HIP 41277 |
28.38 |
| 2026-03-26 12:00 |
08:23:39.30 |
+04:30:56.3 |
HIP 41277 |
28.97 |
| 2026-03-27 00:00 |
08:23:37.24 |
+04:31:12.6 |
HIP 41277 |
29.55 |
| 2026-03-27 12:00 |
08:23:35.20 |
+04:31:28.8 |
HIP 41277 |
30.12 |
| 2026-03-28 00:00 |
08:23:33.20 |
+04:31:45.0 |
HIP 41277 |
30.69 |
| 2026-03-28 12:00 |
08:23:31.22 |
+04:32:01.1 |
HIP 41277 |
31.25 |
| 2026-03-29 00:00 |
08:23:29.28 |
+04:32:17.2 |
HIP 41277 |
31.80 |
| 2026-03-29 12:00 |
08:23:27.36 |
+04:32:33.2 |
HIP 41032 |
32.13 |
| 2026-03-30 00:00 |
08:23:25.48 |
+04:32:49.1 |
HIP 41032 |
31.67 |
| 2026-03-30 12:00 |
08:23:23.62 |
+04:33:05.0 |
HIP 41032 |
31.23 |
| 2026-03-31 00:00 |
08:23:21.80 |
+04:33:20.8 |
HIP 41032 |
30.79 |
| 2026-03-31 12:00 |
08:23:20.00 |
+04:33:36.6 |
HIP 41032 |
30.36 |
| 2026-04-01 00:00 |
08:23:18.24 |
+04:33:52.3 |
HIP 41032 |
29.93 |
| 2026-04-01 12:00 |
08:23:16.51 |
+04:34:07.9 |
HIP 41032 |
29.51 |
| 2026-04-02 00:00 |
08:23:14.81 |
+04:34:23.5 |
HIP 41032 |
29.10 |
| 2026-04-02 12:00 |
08:23:13.14 |
+04:34:39.0 |
HIP 41032 |
28.70 |
| 2026-04-03 00:00 |
08:23:11.50 |
+04:34:54.4 |
HIP 41032 |
28.30 |
| 2026-04-03 12:00 |
08:23:09.89 |
+04:35:09.8 |
HIP 41032 |
27.91 |
| 2026-04-04 00:00 |
08:23:08.31 |
+04:35:25.1 |
HIP 41032 |
27.53 |
| 2026-04-04 12:00 |
08:23:06.76 |
+04:35:40.3 |
HIP 41032 |
27.15 |
| 2026-04-05 00:00 |
08:23:05.24 |
+04:35:55.5 |
HIP 41032 |
26.78 |
| 2026-04-05 12:00 |
08:23:03.76 |
+04:36:10.6 |
HIP 41032 |
26.41 |
| 2026-04-06 00:00 |
08:23:02.30 |
+04:36:25.6 |
HIP 41032 |
26.05 |
| 2026-04-06 12:00 |
08:23:00.88 |
+04:36:40.5 |
HIP 41032 |
25.70 |
| 2026-04-07 00:00 |
08:22:59.49 |
+04:36:55.4 |
HIP 41032 |
25.35 |
| 2026-04-07 12:00 |
08:22:58.13 |
+04:37:10.1 |
HIP 41032 |
25.02 |
| 2026-04-08 00:00 |
08:22:56.80 |
+04:37:24.8 |
HIP 41032 |
24.68 |
| 2026-04-08 12:00 |
08:22:55.50 |
+04:37:39.4 |
HIP 41032 |
24.35 |
| 2026-04-09 00:00 |
08:22:54.23 |
+04:37:54.0 |
HIP 41032 |
24.03 |
| 2026-04-09 12:00 |
08:22:53.00 |
+04:38:08.4 |
HIP 41032 |
23.71 |
| 2026-04-10 00:00 |
08:22:51.80 |
+04:38:22.8 |
HIP 41032 |
23.40 |
| 2026-04-10 12:00 |
08:22:50.62 |
+04:38:37.1 |
HIP 41032 |
23.10 |
| 2026-04-11 00:00 |
08:22:49.48 |
+04:38:51.3 |
HIP 41032 |
22.80 |
| 2026-04-11 12:00 |
08:22:48.38 |
+04:39:05.4 |
HIP 41032 |
22.50 |
| 2026-04-12 00:00 |
08:22:47.30 |
+04:39:19.4 |
HIP 41032 |
22.22 |
| 2026-04-12 12:00 |
08:22:46.25 |
+04:39:33.3 |
HIP 41032 |
21.93 |
| 2026-04-13 00:00 |
08:22:45.24 |
+04:39:47.1 |
HIP 41032 |
21.65 |
| 2026-04-13 12:00 |
08:22:44.26 |
+04:40:00.9 |
HIP 41032 |
21.38 |
| 2026-04-14 00:00 |
08:22:43.31 |
+04:40:14.5 |
HIP 41032 |
21.11 |
| 2026-04-14 12:00 |
08:22:42.39 |
+04:40:28.1 |
HIP 41032 |
20.85 |
| 2026-04-15 00:00 |
08:22:41.51 |
+04:40:41.5 |
HIP 41032 |
20.59 |
| 2026-04-15 12:00 |
08:22:40.65 |
+04:40:54.9 |
HIP 41032 |
20.33 |
| 2026-04-16 00:00 |
08:22:39.83 |
+04:41:08.2 |
HIP 41032 |
20.08 |