| 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
$$
M_a = (10.775 + 2.529\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.775 |
| n |
2.529 |
| gf |
0.926 |
| gb |
-1.000 |
| k |
0.994 |
| δ90 |
9.428 |
| 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) |
| 2026-07-29 00:00 |
08:28:52.11 |
+04:37:41.3 |
HIP 41605 |
10.80 |
| 2026-07-29 12:00 |
08:28:55.29 |
+04:37:25.9 |
HIP 41605 |
11.04 |
| 2026-07-30 00:00 |
08:28:58.48 |
+04:37:10.4 |
HIP 41605 |
11.33 |
| 2026-07-30 12:00 |
08:29:01.67 |
+04:36:54.7 |
HIP 41605 |
11.68 |
| 2026-07-31 00:00 |
08:29:04.85 |
+04:36:38.9 |
HIP 41605 |
12.08 |
| 2026-07-31 12:00 |
08:29:08.03 |
+04:36:23.1 |
HIP 41605 |
12.52 |
| 2026-08-01 00:00 |
08:29:11.21 |
+04:36:07.1 |
HIP 41605 |
13.01 |
| 2026-08-01 12:00 |
08:29:14.39 |
+04:35:51.0 |
HIP 41605 |
13.53 |
| 2026-08-02 00:00 |
08:29:17.56 |
+04:35:34.8 |
HIP 41605 |
14.08 |
| 2026-08-02 12:00 |
08:29:20.73 |
+04:35:18.6 |
HIP 41605 |
14.66 |
| 2026-08-03 00:00 |
08:29:23.90 |
+04:35:02.2 |
HIP 41605 |
15.26 |
| 2026-08-03 12:00 |
08:29:27.07 |
+04:34:45.7 |
HIP 41605 |
15.89 |
| 2026-08-04 00:00 |
08:29:30.23 |
+04:34:29.1 |
HIP 41605 |
16.53 |
| 2026-08-04 12:00 |
08:29:33.39 |
+04:34:12.4 |
HIP 41605 |
17.20 |
| 2026-08-05 00:00 |
08:29:36.55 |
+04:33:55.6 |
HIP 41605 |
17.88 |
| 2026-08-05 12:00 |
08:29:39.70 |
+04:33:38.7 |
HIP 41605 |
18.57 |
| 2026-08-06 00:00 |
08:29:42.85 |
+04:33:21.7 |
HIP 41605 |
19.27 |
| 2026-08-06 12:00 |
08:29:46.00 |
+04:33:04.7 |
HIP 41605 |
19.99 |
| 2026-08-07 00:00 |
08:29:49.14 |
+04:32:47.5 |
HIP 41605 |
20.71 |
| 2026-08-07 12:00 |
08:29:52.27 |
+04:32:30.2 |
HIP 41605 |
21.44 |
| 2026-08-08 00:00 |
08:29:55.40 |
+04:32:12.9 |
HIP 41605 |
22.18 |
| 2026-08-08 12:00 |
08:29:58.53 |
+04:31:55.4 |
HIP 41605 |
22.93 |
| 2026-08-09 00:00 |
08:30:01.65 |
+04:31:37.8 |
HIP 41605 |
23.68 |
| 2026-08-09 12:00 |
08:30:04.76 |
+04:31:20.2 |
HIP 41605 |
24.44 |
| 2026-08-10 00:00 |
08:30:07.87 |
+04:31:02.5 |
HIP 41605 |
25.20 |
| 2026-08-10 12:00 |
08:30:10.97 |
+04:30:44.6 |
HIP 41705 |
25.06 |
| 2026-08-11 00:00 |
08:30:14.07 |
+04:30:26.7 |
HIP 41705 |
24.73 |
| 2026-08-11 12:00 |
08:30:17.16 |
+04:30:08.7 |
HIP 41705 |
24.42 |
| 2026-08-12 00:00 |
08:30:20.24 |
+04:29:50.6 |
HIP 41705 |
24.14 |
| 2026-08-12 12:00 |
08:30:23.32 |
+04:29:32.5 |
HIP 41705 |
23.88 |
| 2026-08-13 00:00 |
08:30:26.38 |
+04:29:14.2 |
HIP 41705 |
23.65 |
| 2026-08-13 12:00 |
08:30:29.44 |
+04:28:55.9 |
HIP 41705 |
23.44 |
| 2026-08-14 00:00 |
08:30:32.50 |
+04:28:37.4 |
HIP 41705 |
23.25 |
| 2026-08-14 12:00 |
08:30:35.54 |
+04:28:18.9 |
HIP 41705 |
23.09 |
| 2026-08-15 00:00 |
08:30:38.58 |
+04:28:00.4 |
HIP 41705 |
22.96 |
| 2026-08-15 12:00 |
08:30:41.60 |
+04:27:41.7 |
HIP 41705 |
22.85 |
| 2026-08-16 00:00 |
08:30:44.62 |
+04:27:23.0 |
HIP 41705 |
22.77 |
| 2026-08-16 12:00 |
08:30:47.63 |
+04:27:04.1 |
HIP 41705 |
22.72 |
| 2026-08-17 00:00 |
08:30:50.63 |
+04:26:45.3 |
HIP 41705 |
22.70 |
| 2026-08-17 12:00 |
08:30:53.62 |
+04:26:26.3 |
HIP 41705 |
22.70 |
| 2026-08-18 00:00 |
08:30:56.61 |
+04:26:07.3 |
HIP 41705 |
22.73 |
| 2026-08-18 12:00 |
08:30:59.58 |
+04:25:48.1 |
HIP 41705 |
22.78 |
| 2026-08-19 00:00 |
08:31:02.54 |
+04:25:29.0 |
HIP 41705 |
22.86 |