| 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) |
| 2026-07-29 00:00 |
13:53:34.10 |
+75:01:06.0 |
HIP 68072 |
21.12 |
| 2026-07-29 12:00 |
13:53:35.07 |
+75:00:08.7 |
HIP 68072 |
20.27 |
| 2026-07-30 00:00 |
13:53:36.14 |
+74:59:11.5 |
HIP 68072 |
19.42 |
| 2026-07-30 12:00 |
13:53:37.33 |
+74:58:14.4 |
HIP 68072 |
18.58 |
| 2026-07-31 00:00 |
13:53:38.63 |
+74:57:17.3 |
HIP 68072 |
17.75 |
| 2026-07-31 12:00 |
13:53:40.03 |
+74:56:20.2 |
HIP 68072 |
16.93 |
| 2026-08-01 00:00 |
13:53:41.55 |
+74:55:23.2 |
HIP 68072 |
16.12 |
| 2026-08-01 12:00 |
13:53:43.18 |
+74:54:26.3 |
HIP 68072 |
15.32 |
| 2026-08-02 00:00 |
13:53:44.92 |
+74:53:29.4 |
HIP 68072 |
14.54 |
| 2026-08-02 12:00 |
13:53:46.76 |
+74:52:32.7 |
HIP 68072 |
13.78 |
| 2026-08-03 00:00 |
13:53:48.72 |
+74:51:35.9 |
HIP 68072 |
13.03 |
| 2026-08-03 12:00 |
13:53:50.78 |
+74:50:39.3 |
HIP 68072 |
12.31 |
| 2026-08-04 00:00 |
13:53:52.95 |
+74:49:42.7 |
HIP 68072 |
11.62 |
| 2026-08-04 12:00 |
13:53:55.23 |
+74:48:46.2 |
HIP 68072 |
10.96 |
| 2026-08-05 00:00 |
13:53:57.61 |
+74:47:49.8 |
HIP 68072 |
10.34 |
| 2026-08-05 12:00 |
13:54:00.10 |
+74:46:53.5 |
HIP 68072 |
9.78 |
| 2026-08-06 00:00 |
13:54:02.69 |
+74:45:57.3 |
HIP 68072 |
9.26 |
| 2026-08-06 12:00 |
13:54:05.39 |
+74:45:01.2 |
HIP 68072 |
8.82 |
| 2026-08-07 00:00 |
13:54:08.20 |
+74:44:05.1 |
HIP 68072 |
8.45 |
| 2026-08-07 12:00 |
13:54:11.11 |
+74:43:09.2 |
HIP 68072 |
8.17 |
| 2026-08-08 00:00 |
13:54:14.12 |
+74:42:13.4 |
HIP 68072 |
7.98 |
| 2026-08-08 12:00 |
13:54:17.24 |
+74:41:17.7 |
HIP 68072 |
7.90 |
| 2026-08-09 00:00 |
13:54:20.46 |
+74:40:22.1 |
HIP 68072 |
7.93 |
| 2026-08-09 12:00 |
13:54:23.78 |
+74:39:26.6 |
HIP 68072 |
8.06 |
| 2026-08-10 00:00 |
13:54:27.20 |
+74:38:31.3 |
HIP 68072 |
8.29 |
| 2026-08-10 12:00 |
13:54:30.73 |
+74:37:36.1 |
HIP 68072 |
8.61 |
| 2026-08-11 00:00 |
13:54:34.36 |
+74:36:41.0 |
HIP 68072 |
9.01 |
| 2026-08-11 12:00 |
13:54:38.09 |
+74:35:46.0 |
HIP 68072 |
9.49 |
| 2026-08-12 00:00 |
13:54:41.91 |
+74:34:51.2 |
HIP 68072 |
10.03 |
| 2026-08-12 12:00 |
13:54:45.84 |
+74:33:56.5 |
HIP 68072 |
10.62 |
| 2026-08-13 00:00 |
13:54:49.87 |
+74:33:02.0 |
HIP 68072 |
11.25 |
| 2026-08-13 12:00 |
13:54:53.99 |
+74:32:07.6 |
HIP 68072 |
11.92 |
| 2026-08-14 00:00 |
13:54:58.22 |
+74:31:13.3 |
HIP 68072 |
12.62 |
| 2026-08-14 12:00 |
13:55:02.54 |
+74:30:19.3 |
HIP 68072 |
13.34 |
| 2026-08-15 00:00 |
13:55:06.95 |
+74:29:25.3 |
HIP 68072 |
14.09 |
| 2026-08-15 12:00 |
13:55:11.47 |
+74:28:31.6 |
HIP 68072 |
14.86 |
| 2026-08-16 00:00 |
13:55:16.08 |
+74:27:38.0 |
HIP 68072 |
15.64 |
| 2026-08-16 12:00 |
13:55:20.78 |
+74:26:44.6 |
HIP 68072 |
16.43 |
| 2026-08-17 00:00 |
13:55:25.58 |
+74:25:51.3 |
HIP 68072 |
17.23 |
| 2026-08-17 12:00 |
13:55:30.47 |
+74:24:58.2 |
HIP 68072 |
18.05 |
| 2026-08-18 00:00 |
13:55:35.45 |
+74:24:05.3 |
HIP 68072 |
18.87 |
| 2026-08-18 12:00 |
13:55:40.53 |
+74:23:12.6 |
HIP 68072 |
19.70 |
| 2026-08-19 00:00 |
13:55:45.69 |
+74:22:20.1 |
HIP 68072 |
20.53 |