| Parameter |
Value |
| Designation |
C/2009 S3 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2011-12-11T06:01:00.886080Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:31:34Z |
| Obs used |
278 |
| NEO |
- |
| M1 |
11.700 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2011-11-26.0000000 |
| e |
1.00141917 |
| q (au) |
6.474515 |
| a (au) |
-4562.197370 |
| i (deg) |
60.384601 |
| Ω (om, deg) |
225.132530 |
| ω (w, deg) |
129.760860 |
| M (ma, deg) |
-0.000049 |
Magnitude
Scatter + Global Linear
$$
M_a = (3.843 + 4.920\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
3.843 |
| n |
4.920 |
| gf |
0.872 |
| gb |
-0.998 |
| k |
1.000 |
| δ90 |
7.536 |
| 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 |
06:39:25.72 |
-31:43:42.9 |
HIP 31824 |
6.81 |
| 2026-07-29 12:00 |
06:39:30.39 |
-31:44:11.9 |
HIP 31824 |
6.77 |
| 2026-07-30 00:00 |
06:39:35.04 |
-31:44:41.3 |
HIP 31824 |
6.90 |
| 2026-07-30 12:00 |
06:39:39.68 |
-31:45:11.0 |
HIP 31824 |
7.20 |
| 2026-07-31 00:00 |
06:39:44.29 |
-31:45:41.0 |
HIP 31824 |
7.64 |
| 2026-07-31 12:00 |
06:39:48.89 |
-31:46:11.4 |
HIP 31824 |
8.19 |
| 2026-08-01 00:00 |
06:39:53.47 |
-31:46:42.2 |
HIP 31824 |
8.85 |
| 2026-08-01 12:00 |
06:39:58.04 |
-31:47:13.3 |
HIP 31824 |
9.58 |
| 2026-08-02 00:00 |
06:40:02.58 |
-31:47:44.7 |
HIP 31824 |
10.37 |
| 2026-08-02 12:00 |
06:40:07.11 |
-31:48:16.5 |
HIP 31824 |
11.20 |
| 2026-08-03 00:00 |
06:40:11.61 |
-31:48:48.6 |
HIP 31824 |
12.08 |
| 2026-08-03 12:00 |
06:40:16.10 |
-31:49:21.0 |
HIP 31824 |
12.98 |
| 2026-08-04 00:00 |
06:40:20.57 |
-31:49:53.8 |
HIP 31824 |
13.91 |
| 2026-08-04 12:00 |
06:40:25.01 |
-31:50:26.9 |
HIP 31824 |
14.85 |
| 2026-08-05 00:00 |
06:40:29.44 |
-31:51:00.3 |
HIP 31824 |
15.81 |
| 2026-08-05 12:00 |
06:40:33.84 |
-31:51:34.1 |
HIP 31824 |
16.78 |
| 2026-08-06 00:00 |
06:40:38.23 |
-31:52:08.2 |
HIP 31824 |
17.77 |
| 2026-08-06 12:00 |
06:40:42.59 |
-31:52:42.7 |
HIP 31824 |
18.76 |
| 2026-08-07 00:00 |
06:40:46.94 |
-31:53:17.4 |
HIP 31824 |
19.75 |
| 2026-08-07 12:00 |
06:40:51.26 |
-31:53:52.5 |
HIP 31824 |
20.76 |
| 2026-08-08 00:00 |
06:40:55.56 |
-31:54:27.9 |
HIP 31824 |
21.76 |
| 2026-08-08 12:00 |
06:40:59.84 |
-31:55:03.6 |
HIP 32096 |
22.62 |
| 2026-08-09 00:00 |
06:41:04.09 |
-31:55:39.7 |
HIP 32096 |
22.37 |
| 2026-08-09 12:00 |
06:41:08.32 |
-31:56:16.1 |
HIP 32096 |
22.18 |
| 2026-08-10 00:00 |
06:41:12.53 |
-31:56:52.8 |
HIP 32096 |
22.05 |
| 2026-08-10 12:00 |
06:41:16.72 |
-31:57:29.8 |
HIP 32096 |
21.98 |
| 2026-08-11 00:00 |
06:41:20.88 |
-31:58:07.1 |
HIP 32096 |
21.97 |
| 2026-08-11 12:00 |
06:41:25.02 |
-31:58:44.7 |
HIP 32096 |
22.02 |
| 2026-08-12 00:00 |
06:41:29.13 |
-31:59:22.6 |
HIP 32096 |
22.12 |
| 2026-08-12 12:00 |
06:41:33.22 |
-32:00:00.9 |
HIP 32096 |
22.29 |
| 2026-08-13 00:00 |
06:41:37.29 |
-32:00:39.4 |
HIP 32096 |
22.52 |
| 2026-08-13 12:00 |
06:41:41.33 |
-32:01:18.3 |
HIP 32096 |
22.80 |
| 2026-08-14 00:00 |
06:41:45.34 |
-32:01:57.4 |
HIP 32096 |
23.13 |
| 2026-08-14 12:00 |
06:41:49.33 |
-32:02:36.9 |
HIP 32096 |
23.52 |
| 2026-08-15 00:00 |
06:41:53.30 |
-32:03:16.6 |
HIP 32096 |
23.95 |
| 2026-08-15 12:00 |
06:41:57.23 |
-32:03:56.6 |
HIP 32096 |
24.43 |
| 2026-08-16 00:00 |
06:42:01.15 |
-32:04:36.9 |
HIP 32096 |
24.95 |
| 2026-08-16 12:00 |
06:42:05.03 |
-32:05:17.5 |
HIP 32096 |
25.51 |
| 2026-08-17 00:00 |
06:42:08.89 |
-32:05:58.4 |
HIP 32096 |
26.10 |
| 2026-08-17 12:00 |
06:42:12.72 |
-32:06:39.6 |
HIP 32096 |
26.73 |
| 2026-08-18 00:00 |
06:42:16.53 |
-32:07:21.1 |
HIP 32096 |
27.39 |
| 2026-08-18 12:00 |
06:42:20.30 |
-32:08:02.8 |
HIP 32248 |
27.36 |
| 2026-08-19 00:00 |
06:42:24.05 |
-32:08:44.8 |
HIP 32248 |
26.31 |