| 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) |
| 2026-05-12 00:00 |
08:22:40.21 |
+04:49:57.6 |
HIP 41032 |
11.48 |
| 2026-05-12 12:00 |
08:22:41.02 |
+04:50:04.3 |
HIP 41032 |
11.43 |
| 2026-05-13 00:00 |
08:22:41.86 |
+04:50:10.9 |
HIP 41032 |
11.39 |
| 2026-05-13 12:00 |
08:22:42.72 |
+04:50:17.4 |
HIP 41032 |
11.36 |
| 2026-05-14 00:00 |
08:22:43.61 |
+04:50:23.7 |
HIP 41032 |
11.34 |
| 2026-05-14 12:00 |
08:22:44.53 |
+04:50:29.9 |
HIP 41032 |
11.32 |
| 2026-05-15 00:00 |
08:22:45.48 |
+04:50:36.0 |
HIP 41032 |
11.32 |
| 2026-05-15 12:00 |
08:22:46.46 |
+04:50:41.9 |
HIP 41032 |
11.34 |
| 2026-05-16 00:00 |
08:22:47.46 |
+04:50:47.6 |
HIP 41032 |
11.36 |
| 2026-05-16 12:00 |
08:22:48.49 |
+04:50:53.2 |
HIP 41032 |
11.39 |
| 2026-05-17 00:00 |
08:22:49.55 |
+04:50:58.7 |
HIP 41032 |
11.44 |
| 2026-05-17 12:00 |
08:22:50.64 |
+04:51:04.0 |
HIP 41032 |
11.50 |
| 2026-05-18 00:00 |
08:22:51.76 |
+04:51:09.1 |
HIP 41032 |
11.57 |
| 2026-05-18 12:00 |
08:22:52.90 |
+04:51:14.2 |
HIP 41032 |
11.65 |
| 2026-05-19 00:00 |
08:22:54.07 |
+04:51:19.0 |
HIP 41032 |
11.75 |
| 2026-05-19 12:00 |
08:22:55.27 |
+04:51:23.7 |
HIP 41032 |
11.86 |
| 2026-05-20 00:00 |
08:22:56.50 |
+04:51:28.3 |
HIP 41032 |
11.98 |
| 2026-05-20 12:00 |
08:22:57.75 |
+04:51:32.7 |
HIP 41032 |
12.11 |
| 2026-05-21 00:00 |
08:22:59.03 |
+04:51:37.0 |
HIP 41032 |
12.26 |
| 2026-05-21 12:00 |
08:23:00.33 |
+04:51:41.1 |
HIP 41032 |
12.42 |
| 2026-05-22 00:00 |
08:23:01.66 |
+04:51:45.1 |
HIP 41032 |
12.60 |
| 2026-05-22 12:00 |
08:23:03.02 |
+04:51:48.9 |
HIP 41032 |
12.78 |
| 2026-05-23 00:00 |
08:23:04.40 |
+04:51:52.6 |
HIP 41032 |
12.98 |
| 2026-05-23 12:00 |
08:23:05.81 |
+04:51:56.1 |
HIP 41032 |
13.20 |
| 2026-05-24 00:00 |
08:23:07.24 |
+04:51:59.5 |
HIP 41032 |
13.42 |
| 2026-05-24 12:00 |
08:23:08.70 |
+04:52:02.7 |
HIP 41032 |
13.66 |
| 2026-05-25 00:00 |
08:23:10.19 |
+04:52:05.8 |
HIP 41032 |
13.91 |
| 2026-05-25 12:00 |
08:23:11.70 |
+04:52:08.7 |
HIP 41032 |
14.17 |
| 2026-05-26 00:00 |
08:23:13.24 |
+04:52:11.5 |
HIP 41032 |
14.44 |
| 2026-05-26 12:00 |
08:23:14.80 |
+04:52:14.1 |
HIP 41032 |
14.73 |
| 2026-05-27 00:00 |
08:23:16.38 |
+04:52:16.6 |
HIP 41032 |
15.02 |
| 2026-05-27 12:00 |
08:23:17.99 |
+04:52:18.9 |
HIP 41032 |
15.33 |
| 2026-05-28 00:00 |
08:23:19.62 |
+04:52:21.1 |
HIP 41032 |
15.65 |
| 2026-05-28 12:00 |
08:23:21.28 |
+04:52:23.1 |
HIP 41032 |
15.98 |
| 2026-05-29 00:00 |
08:23:22.96 |
+04:52:24.9 |
HIP 41032 |
16.31 |
| 2026-05-29 12:00 |
08:23:24.67 |
+04:52:26.7 |
HIP 41032 |
16.66 |
| 2026-05-30 00:00 |
08:23:26.40 |
+04:52:28.2 |
HIP 41032 |
17.02 |
| 2026-05-30 12:00 |
08:23:28.15 |
+04:52:29.6 |
HIP 41032 |
17.39 |
| 2026-05-31 00:00 |
08:23:29.93 |
+04:52:30.9 |
HIP 41032 |
17.77 |
| 2026-05-31 12:00 |
08:23:31.73 |
+04:52:32.0 |
HIP 41032 |
18.15 |
| 2026-06-01 00:00 |
08:23:33.56 |
+04:52:32.9 |
HIP 41032 |
18.55 |
| 2026-06-01 12:00 |
08:23:35.40 |
+04:52:33.7 |
HIP 41032 |
18.96 |
| 2026-06-02 00:00 |
08:23:37.27 |
+04:52:34.4 |
HIP 41032 |
19.37 |