| Parameter |
Value |
| Designation |
C/2012 F6 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2013-03-24T12:20:06.757440Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:32:07Z |
| Obs used |
3201 |
| NEO |
- |
| M1 |
5.600 |
| K1 |
14.750 |
| PC |
0.030 |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2013-07-29.0000000 |
| e |
0.99849892 |
| q (au) |
0.731238 |
| a (au) |
487.140054 |
| i (deg) |
82.608873 |
| Ω (om, deg) |
332.715296 |
| ω (w, deg) |
304.986917 |
| M (ma, deg) |
0.011595 |
Magnitude
Scatter + Global Linear
$$
M_a = (6.992 + 5.601\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.992 |
| n |
5.601 |
| gf |
0.993 |
| gb |
-0.972 |
| k |
0.966 |
| δ90 |
9.945 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2012-01-22 |
2013-01-26 |
+10.6291 |
-3.477 |
| 2013-01-26 |
2013-02-05 |
-5.2545 |
-0.788 |
| 2013-02-05 |
2013-03-14 |
+0.6990 |
-1.791 |
| 2013-04-01 |
2013-06-19 |
+4.0507 |
-1.366 |
| 2013-06-19 |
2013-07-13 |
-5.5477 |
+1.307 |
| 2013-07-13 |
2013-08-08 |
-11.8318 |
+3.586 |
| 2013-08-08 |
2014-10-27 |
+0.7308 |
-0.852 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
14:03:59.98 |
+73:34:51.6 |
HIP 68382 |
20.82 |
| 2026-09-20 12:00 |
14:04:09.84 |
+73:34:17.1 |
HIP 68382 |
21.14 |
| 2026-09-21 00:00 |
14:04:19.75 |
+73:33:42.8 |
HIP 68382 |
21.49 |
| 2026-09-21 12:00 |
14:04:29.70 |
+73:33:09.0 |
HIP 68382 |
21.88 |
| 2026-09-22 00:00 |
14:04:39.71 |
+73:32:35.5 |
HIP 68382 |
22.31 |
| 2026-09-22 12:00 |
14:04:49.77 |
+73:32:02.3 |
HIP 68382 |
22.78 |
| 2026-09-23 00:00 |
14:04:59.88 |
+73:31:29.6 |
HIP 68382 |
23.27 |
| 2026-09-23 12:00 |
14:05:10.04 |
+73:30:57.2 |
HIP 68382 |
23.79 |
| 2026-09-24 00:00 |
14:05:20.24 |
+73:30:25.1 |
HIP 68382 |
24.35 |
| 2026-09-24 12:00 |
14:05:30.49 |
+73:29:53.5 |
HIP 68382 |
24.92 |
| 2026-09-25 00:00 |
14:05:40.79 |
+73:29:22.2 |
HIP 69303 |
24.69 |
| 2026-09-25 12:00 |
14:05:51.14 |
+73:28:51.2 |
HIP 69303 |
23.82 |
| 2026-09-26 00:00 |
14:06:01.53 |
+73:28:20.7 |
HIP 69303 |
22.96 |
| 2026-09-26 12:00 |
14:06:11.96 |
+73:27:50.5 |
HIP 69303 |
22.10 |
| 2026-09-27 00:00 |
14:06:22.44 |
+73:27:20.7 |
HIP 69303 |
21.24 |
| 2026-09-27 12:00 |
14:06:32.97 |
+73:26:51.3 |
HIP 69303 |
20.38 |
| 2026-09-28 00:00 |
14:06:43.53 |
+73:26:22.2 |
HIP 69303 |
19.52 |
| 2026-09-28 12:00 |
14:06:54.14 |
+73:25:53.6 |
HIP 69303 |
18.66 |
| 2026-09-29 00:00 |
14:07:04.80 |
+73:25:25.3 |
HIP 69303 |
17.81 |
| 2026-09-29 12:00 |
14:07:15.49 |
+73:24:57.4 |
HIP 69303 |
16.95 |
| 2026-09-30 00:00 |
14:07:26.22 |
+73:24:29.9 |
HIP 69303 |
16.10 |
| 2026-09-30 12:00 |
14:07:37.00 |
+73:24:02.8 |
HIP 69303 |
15.26 |
| 2026-10-01 00:00 |
14:07:47.81 |
+73:23:36.1 |
HIP 69303 |
14.41 |
| 2026-10-01 12:00 |
14:07:58.67 |
+73:23:09.7 |
HIP 69303 |
13.57 |
| 2026-10-02 00:00 |
14:08:09.56 |
+73:22:43.8 |
HIP 69303 |
12.74 |
| 2026-10-02 12:00 |
14:08:20.49 |
+73:22:18.3 |
HIP 69303 |
11.90 |
| 2026-10-03 00:00 |
14:08:31.46 |
+73:21:53.1 |
HIP 69303 |
11.08 |
| 2026-10-03 12:00 |
14:08:42.47 |
+73:21:28.4 |
HIP 69303 |
10.26 |
| 2026-10-04 00:00 |
14:08:53.51 |
+73:21:04.1 |
HIP 69303 |
9.46 |
| 2026-10-04 12:00 |
14:09:04.59 |
+73:20:40.1 |
HIP 69303 |
8.67 |
| 2026-10-05 00:00 |
14:09:15.70 |
+73:20:16.6 |
HIP 69303 |
7.89 |
| 2026-10-05 12:00 |
14:09:26.85 |
+73:19:53.5 |
HIP 69303 |
7.14 |
| 2026-10-06 00:00 |
14:09:38.03 |
+73:19:30.8 |
HIP 69303 |
6.41 |
| 2026-10-06 12:00 |
14:09:49.25 |
+73:19:08.5 |
HIP 69303 |
5.73 |
| 2026-10-07 00:00 |
14:10:00.50 |
+73:18:46.6 |
HIP 69303 |
5.10 |
| 2026-10-07 12:00 |
14:10:11.78 |
+73:18:25.1 |
HIP 69303 |
4.55 |
| 2026-10-08 00:00 |
14:10:23.09 |
+73:18:04.0 |
HIP 69303 |
4.12 |
| 2026-10-08 12:00 |
14:10:34.43 |
+73:17:43.4 |
HIP 69303 |
3.83 |
| 2026-10-09 00:00 |
14:10:45.80 |
+73:17:23.2 |
HIP 69303 |
3.73 |
| 2026-10-09 12:00 |
14:10:57.21 |
+73:17:03.4 |
HIP 69303 |
3.83 |
| 2026-10-10 00:00 |
14:11:08.64 |
+73:16:44.0 |
HIP 69303 |
4.11 |
| 2026-10-10 12:00 |
14:11:20.10 |
+73:16:25.1 |
HIP 69303 |
4.54 |
| 2026-10-11 00:00 |
14:11:31.58 |
+73:16:06.5 |
HIP 69303 |
5.09 |