| 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 |
9.940 |
| 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 |
+10.6292 |
-3.477 |
| 2013-01-26 |
2013-02-05 |
-5.2552 |
-0.788 |
| 2013-02-05 |
2013-03-14 |
+0.6982 |
-1.791 |
| 2013-04-01 |
2013-06-19 |
+4.0499 |
-1.366 |
| 2013-06-19 |
2013-07-13 |
-5.5480 |
+1.307 |
| 2013-07-13 |
2013-08-08 |
-11.8322 |
+3.586 |
| 2013-08-08 |
2014-10-27 |
+0.7307 |
-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) |
| 2026-03-26 00:00 |
14:40:29.78 |
+76:40:15.1 |
HIP 72340 |
25.87 |
| 2026-03-26 12:00 |
14:40:16.21 |
+76:40:50.0 |
HIP 72340 |
26.41 |
| 2026-03-27 00:00 |
14:40:02.54 |
+76:41:24.4 |
HIP 72340 |
26.97 |
| 2026-03-27 12:00 |
14:39:48.78 |
+76:41:58.3 |
HIP 72340 |
27.56 |
| 2026-03-28 00:00 |
14:39:34.91 |
+76:42:31.7 |
HIP 72340 |
28.18 |
| 2026-03-28 12:00 |
14:39:20.95 |
+76:43:04.7 |
HIP 72340 |
28.82 |
| 2026-03-29 00:00 |
14:39:06.90 |
+76:43:37.2 |
HIP 70985 |
29.17 |
| 2026-03-29 12:00 |
14:38:52.76 |
+76:44:09.2 |
HIP 70985 |
28.58 |
| 2026-03-30 00:00 |
14:38:38.52 |
+76:44:40.7 |
HIP 70985 |
28.01 |
| 2026-03-30 12:00 |
14:38:24.19 |
+76:45:11.7 |
HIP 70985 |
27.45 |
| 2026-03-31 00:00 |
14:38:09.77 |
+76:45:42.2 |
HIP 70985 |
26.90 |
| 2026-03-31 12:00 |
14:37:55.27 |
+76:46:12.3 |
HIP 70985 |
26.38 |
| 2026-04-01 00:00 |
14:37:40.68 |
+76:46:41.8 |
HIP 70985 |
25.87 |
| 2026-04-01 12:00 |
14:37:26.00 |
+76:47:10.9 |
HIP 70985 |
25.38 |
| 2026-04-02 00:00 |
14:37:11.24 |
+76:47:39.4 |
HIP 70985 |
24.91 |
| 2026-04-02 12:00 |
14:36:56.39 |
+76:48:07.5 |
HIP 70985 |
24.47 |
| 2026-04-03 00:00 |
14:36:41.47 |
+76:48:35.0 |
HIP 70985 |
24.05 |
| 2026-04-03 12:00 |
14:36:26.46 |
+76:49:02.0 |
HIP 70985 |
23.65 |
| 2026-04-04 00:00 |
14:36:11.38 |
+76:49:28.5 |
HIP 70985 |
23.28 |
| 2026-04-04 12:00 |
14:35:56.22 |
+76:49:54.5 |
HIP 70985 |
22.93 |
| 2026-04-05 00:00 |
14:35:40.98 |
+76:50:20.0 |
HIP 70985 |
22.62 |
| 2026-04-05 12:00 |
14:35:25.67 |
+76:50:45.0 |
HIP 70985 |
22.33 |
| 2026-04-06 00:00 |
14:35:10.29 |
+76:51:09.4 |
HIP 70985 |
22.07 |
| 2026-04-06 12:00 |
14:34:54.83 |
+76:51:33.4 |
HIP 70985 |
21.85 |
| 2026-04-07 00:00 |
14:34:39.31 |
+76:51:56.8 |
HIP 70985 |
21.66 |
| 2026-04-07 12:00 |
14:34:23.71 |
+76:52:19.7 |
HIP 70985 |
21.50 |
| 2026-04-08 00:00 |
14:34:08.05 |
+76:52:42.0 |
HIP 70985 |
21.37 |
| 2026-04-08 12:00 |
14:33:52.33 |
+76:53:03.8 |
HIP 70985 |
21.28 |
| 2026-04-09 00:00 |
14:33:36.54 |
+76:53:25.1 |
HIP 70985 |
21.23 |
| 2026-04-09 12:00 |
14:33:20.68 |
+76:53:45.8 |
HIP 70985 |
21.21 |
| 2026-04-10 00:00 |
14:33:04.77 |
+76:54:06.1 |
HIP 70985 |
21.22 |
| 2026-04-10 12:00 |
14:32:48.80 |
+76:54:25.7 |
HIP 70985 |
21.27 |
| 2026-04-11 00:00 |
14:32:32.77 |
+76:54:44.8 |
HIP 70985 |
21.36 |
| 2026-04-11 12:00 |
14:32:16.68 |
+76:55:03.4 |
HIP 70985 |
21.48 |
| 2026-04-12 00:00 |
14:32:00.54 |
+76:55:21.5 |
HIP 70985 |
21.63 |
| 2026-04-12 12:00 |
14:31:44.35 |
+76:55:39.0 |
HIP 70985 |
21.82 |
| 2026-04-13 00:00 |
14:31:28.10 |
+76:55:55.9 |
HIP 70985 |
22.04 |
| 2026-04-13 12:00 |
14:31:11.81 |
+76:56:12.3 |
HIP 70985 |
22.29 |
| 2026-04-14 00:00 |
14:30:55.47 |
+76:56:28.1 |
HIP 70985 |
22.57 |
| 2026-04-14 12:00 |
14:30:39.08 |
+76:56:43.4 |
HIP 70985 |
22.88 |
| 2026-04-15 00:00 |
14:30:22.65 |
+76:56:58.1 |
HIP 70985 |
23.21 |
| 2026-04-15 12:00 |
14:30:06.17 |
+76:57:12.3 |
HIP 70985 |
23.58 |
| 2026-04-16 00:00 |
14:29:49.65 |
+76:57:25.9 |
HIP 70807 |
23.40 |