C/2012 F6 (Lemmon)
| 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
$$
M_a = (6.993 + 5.600\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
6.993 |
| n |
5.600 |
| gf |
0.997 |
| gb |
-0.972 |
| k |
0.966 |
| δ90 |
9.959 |
| 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 |
+10.6306 |
-3.478 |
| 2013-01-26 |
2013-02-05 |
-5.2595 |
-0.788 |
| 2013-02-05 |
2013-03-14 |
+0.7010 |
-1.792 |
| 2013-04-01 |
2013-06-19 |
+4.0514 |
-1.368 |
| 2013-06-19 |
2013-07-13 |
-5.5440 |
+1.305 |
| 2013-07-13 |
2013-08-08 |
-11.7656 |
+3.563 |
| 2013-08-08 |
2014-10-27 |
+0.7118 |
-0.841 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-02-03 00:00 |
14:52:30.76 |
+75:12:34.6 |
HIP 72992 |
21.94 |
| 2026-02-03 12:00 |
14:52:30.58 |
+75:13:34.5 |
HIP 72992 |
22.84 |
| 2026-02-04 00:00 |
14:52:30.26 |
+75:14:34.4 |
HIP 72992 |
23.75 |
| 2026-02-04 12:00 |
14:52:29.80 |
+75:15:34.3 |
HIP 72992 |
24.68 |
| 2026-02-05 00:00 |
14:52:29.22 |
+75:16:34.2 |
HIP 72992 |
25.61 |
| 2026-02-05 12:00 |
14:52:28.50 |
+75:17:34.1 |
HIP 72992 |
26.55 |
| 2026-02-06 00:00 |
14:52:27.64 |
+75:18:33.9 |
HIP 72992 |
27.50 |
| 2026-02-06 12:00 |
14:52:26.65 |
+75:19:33.7 |
HIP 72992 |
28.46 |
| 2026-02-07 00:00 |
14:52:25.53 |
+75:20:33.5 |
HIP 72992 |
29.41 |
| 2026-02-07 12:00 |
14:52:24.27 |
+75:21:33.3 |
HIP 72992 |
30.38 |
| 2026-02-08 00:00 |
14:52:22.88 |
+75:22:33.0 |
HIP 72992 |
31.35 |
| 2026-02-08 12:00 |
14:52:21.34 |
+75:23:32.7 |
HIP 72992 |
32.32 |
| 2026-02-09 00:00 |
14:52:19.68 |
+75:24:32.4 |
HIP 72992 |
33.30 |
| 2026-02-09 12:00 |
14:52:17.87 |
+75:25:32.0 |
HIP 72992 |
34.27 |
| 2026-02-10 00:00 |
14:52:15.93 |
+75:26:31.5 |
HIP 73481 |
34.95 |
| 2026-02-10 12:00 |
14:52:13.85 |
+75:27:30.9 |
HIP 73481 |
35.37 |
| 2026-02-11 00:00 |
14:52:11.63 |
+75:28:30.3 |
HIP 73481 |
35.83 |
| 2026-02-11 12:00 |
14:52:09.27 |
+75:29:29.7 |
HIP 73481 |
36.31 |
| 2026-02-12 00:00 |
14:52:06.78 |
+75:30:28.9 |
HIP 73481 |
36.83 |
| 2026-02-12 12:00 |
14:52:04.15 |
+75:31:28.1 |
HIP 72307 |
35.93 |
| 2026-02-13 00:00 |
14:52:01.37 |
+75:32:27.1 |
HIP 72307 |
34.99 |
| 2026-02-13 12:00 |
14:51:58.46 |
+75:33:26.1 |
HIP 72307 |
34.05 |
| 2026-02-14 00:00 |
14:51:55.41 |
+75:34:25.0 |
HIP 72307 |
33.11 |
| 2026-02-14 12:00 |
14:51:52.21 |
+75:35:23.8 |
HIP 72307 |
32.17 |
| 2026-02-15 00:00 |
14:51:48.88 |
+75:36:22.4 |
HIP 72307 |
31.23 |
| 2026-02-15 12:00 |
14:51:45.41 |
+75:37:21.0 |
HIP 72307 |
30.29 |
| 2026-02-16 00:00 |
14:51:41.79 |
+75:38:19.4 |
HIP 72307 |
29.36 |
| 2026-02-16 12:00 |
14:51:38.04 |
+75:39:17.7 |
HIP 72307 |
28.42 |
| 2026-02-17 00:00 |
14:51:34.14 |
+75:40:15.8 |
HIP 72307 |
27.49 |
| 2026-02-17 12:00 |
14:51:30.11 |
+75:41:13.9 |
HIP 72307 |
26.56 |
| 2026-02-18 00:00 |
14:51:25.93 |
+75:42:11.8 |
HIP 72307 |
25.63 |
| 2026-02-18 12:00 |
14:51:21.61 |
+75:43:09.5 |
HIP 72307 |
24.71 |
| 2026-02-19 00:00 |
14:51:17.15 |
+75:44:07.1 |
HIP 72307 |
23.78 |
| 2026-02-19 12:00 |
14:51:12.55 |
+75:45:04.5 |
HIP 72307 |
22.86 |
| 2026-02-20 00:00 |
14:51:07.80 |
+75:46:01.8 |
HIP 72307 |
21.94 |
| 2026-02-20 12:00 |
14:51:02.92 |
+75:46:58.9 |
HIP 72307 |
21.03 |
| 2026-02-21 00:00 |
14:50:57.90 |
+75:47:55.8 |
HIP 72307 |
20.12 |
| 2026-02-21 12:00 |
14:50:52.73 |
+75:48:52.6 |
HIP 72307 |
19.22 |
| 2026-02-22 00:00 |
14:50:47.42 |
+75:49:49.1 |
HIP 72307 |
18.32 |
| 2026-02-22 12:00 |
14:50:41.97 |
+75:50:45.5 |
HIP 72307 |
17.43 |
| 2026-02-23 00:00 |
14:50:36.39 |
+75:51:41.7 |
HIP 72307 |
16.55 |
| 2026-02-23 12:00 |
14:50:30.66 |
+75:52:37.7 |
HIP 72307 |
15.68 |
| 2026-02-24 00:00 |
14:50:24.79 |
+75:53:33.5 |
HIP 72307 |
14.82 |