| Parameter |
Value |
| Designation |
C/2007 S2 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2008-09-14T20:38:31.534080Z |
| Orbit solution date (soln_date, UTC) |
2024-04-13T16:42:27Z |
| Obs used |
423 |
| NEO |
- |
| M1 |
10.500 |
| K1 |
6.000 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2008-07-02.0000000 |
| e |
0.55701356 |
| q (au) |
5.557956 |
| a (au) |
12.546561 |
| i (deg) |
16.862815 |
| Ω (om, deg) |
296.252831 |
| ω (w, deg) |
210.466010 |
| M (ma, deg) |
358.339773 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.208 + 2.571\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.208 |
| n |
2.571 |
| gf |
1.000 |
| gb |
-0.969 |
| 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) |
| 2026-06-01 00:00 |
21:07:30.41 |
-11:03:19.0 |
HIP 104405 |
27.13 |
| 2026-06-01 12:00 |
21:07:28.60 |
-11:03:14.6 |
HIP 104405 |
27.47 |
| 2026-06-02 00:00 |
21:07:26.74 |
-11:03:10.5 |
HIP 104405 |
27.82 |
| 2026-06-02 12:00 |
21:07:24.83 |
-11:03:06.6 |
HIP 104405 |
28.18 |
| 2026-06-03 00:00 |
21:07:22.87 |
-11:03:02.9 |
HIP 104405 |
28.56 |
| 2026-06-03 12:00 |
21:07:20.87 |
-11:02:59.5 |
HIP 104405 |
28.96 |
| 2026-06-04 00:00 |
21:07:18.82 |
-11:02:56.3 |
HIP 104405 |
29.37 |
| 2026-06-04 12:00 |
21:07:16.72 |
-11:02:53.3 |
HIP 104405 |
29.80 |
| 2026-06-05 00:00 |
21:07:14.58 |
-11:02:50.6 |
HIP 104405 |
30.24 |
| 2026-06-05 12:00 |
21:07:12.39 |
-11:02:48.1 |
HIP 104405 |
30.70 |
| 2026-06-06 00:00 |
21:07:10.15 |
-11:02:45.9 |
HIP 104405 |
31.17 |
| 2026-06-06 12:00 |
21:07:07.86 |
-11:02:43.9 |
HIP 104405 |
31.65 |
| 2026-06-07 00:00 |
21:07:05.53 |
-11:02:42.1 |
HIP 104132 |
31.69 |
| 2026-06-07 12:00 |
21:07:03.15 |
-11:02:40.6 |
HIP 104132 |
31.34 |
| 2026-06-08 00:00 |
21:07:00.73 |
-11:02:39.3 |
HIP 104132 |
30.99 |
| 2026-06-08 12:00 |
21:06:58.25 |
-11:02:38.2 |
HIP 104132 |
30.65 |
| 2026-06-09 00:00 |
21:06:55.74 |
-11:02:37.4 |
HIP 104132 |
30.31 |
| 2026-06-09 12:00 |
21:06:53.17 |
-11:02:36.8 |
HIP 104132 |
29.98 |
| 2026-06-10 00:00 |
21:06:50.57 |
-11:02:36.4 |
HIP 104132 |
29.66 |
| 2026-06-10 12:00 |
21:06:47.91 |
-11:02:36.3 |
HIP 104132 |
29.35 |
| 2026-06-11 00:00 |
21:06:45.21 |
-11:02:36.4 |
HIP 104132 |
29.04 |
| 2026-06-11 12:00 |
21:06:42.47 |
-11:02:36.7 |
HIP 104132 |
28.75 |
| 2026-06-12 00:00 |
21:06:39.68 |
-11:02:37.3 |
HIP 104132 |
28.47 |
| 2026-06-12 12:00 |
21:06:36.85 |
-11:02:38.1 |
HIP 104132 |
28.20 |
| 2026-06-13 00:00 |
21:06:33.97 |
-11:02:39.2 |
HIP 104132 |
27.95 |
| 2026-06-13 12:00 |
21:06:31.05 |
-11:02:40.5 |
HIP 104132 |
27.71 |
| 2026-06-14 00:00 |
21:06:28.08 |
-11:02:42.0 |
HIP 104132 |
27.49 |
| 2026-06-14 12:00 |
21:06:25.07 |
-11:02:43.7 |
HIP 104132 |
27.28 |
| 2026-06-15 00:00 |
21:06:22.02 |
-11:02:45.7 |
HIP 104132 |
27.10 |
| 2026-06-15 12:00 |
21:06:18.92 |
-11:02:47.9 |
HIP 104132 |
26.94 |
| 2026-06-16 00:00 |
21:06:15.78 |
-11:02:50.4 |
HIP 104132 |
26.79 |
| 2026-06-16 12:00 |
21:06:12.60 |
-11:02:53.0 |
HIP 104132 |
26.68 |
| 2026-06-17 00:00 |
21:06:09.38 |
-11:02:55.9 |
HIP 104132 |
26.58 |
| 2026-06-17 12:00 |
21:06:06.11 |
-11:02:59.0 |
HIP 104132 |
26.52 |
| 2026-06-18 00:00 |
21:06:02.81 |
-11:03:02.4 |
HIP 104132 |
26.48 |
| 2026-06-18 12:00 |
21:05:59.46 |
-11:03:06.0 |
HIP 104132 |
26.46 |
| 2026-06-19 00:00 |
21:05:56.07 |
-11:03:09.8 |
HIP 104132 |
26.48 |
| 2026-06-19 12:00 |
21:05:52.64 |
-11:03:13.8 |
HIP 104132 |
26.53 |
| 2026-06-20 00:00 |
21:05:49.17 |
-11:03:18.0 |
HIP 104132 |
26.60 |
| 2026-06-20 12:00 |
21:05:45.66 |
-11:03:22.5 |
HIP 104132 |
26.71 |
| 2026-06-21 00:00 |
21:05:42.11 |
-11:03:27.2 |
HIP 104132 |
26.85 |
| 2026-06-21 12:00 |
21:05:38.53 |
-11:03:32.1 |
HIP 104132 |
27.03 |
| 2026-06-22 00:00 |
21:05:34.90 |
-11:03:37.2 |
HIP 104132 |
27.23 |