| Parameter |
Value |
| Designation |
C/2017 E5 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2016-06-10T21:21:43.948800Z |
| Orbit solution date (soln_date, UTC) |
2022-06-20T23:12:32Z |
| Obs used |
112 |
| NEO |
- |
| M1 |
15.900 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2017-01-12.0000000 |
| e |
0.99563963 |
| q (au) |
1.783311 |
| a (au) |
408.982042 |
| i (deg) |
122.637072 |
| Ω (om, deg) |
206.191666 |
| ω (w, deg) |
306.771175 |
| M (ma, deg) |
0.025634 |
Magnitude
Scatter + Global Linear
$$
M_a = (17.408 + 3.382\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
17.408 |
| n |
3.382 |
| gf |
0.980 |
| gb |
-0.863 |
| k |
0.800 |
| 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) |
| 2026-07-29 00:00 |
08:51:27.53 |
+75:56:15.0 |
HIP 43940 |
27.11 |
| 2026-07-29 12:00 |
08:51:44.54 |
+75:56:03.2 |
HIP 43940 |
26.21 |
| 2026-07-30 00:00 |
08:52:01.55 |
+75:55:51.8 |
HIP 43940 |
25.31 |
| 2026-07-30 12:00 |
08:52:18.57 |
+75:55:40.8 |
HIP 43940 |
24.44 |
| 2026-07-31 00:00 |
08:52:35.59 |
+75:55:30.3 |
HIP 43940 |
23.59 |
| 2026-07-31 12:00 |
08:52:52.60 |
+75:55:20.2 |
HIP 43940 |
22.76 |
| 2026-08-01 00:00 |
08:53:09.62 |
+75:55:10.5 |
HIP 43940 |
21.95 |
| 2026-08-01 12:00 |
08:53:26.64 |
+75:55:01.2 |
HIP 43940 |
21.17 |
| 2026-08-02 00:00 |
08:53:43.66 |
+75:54:52.4 |
HIP 43940 |
20.42 |
| 2026-08-02 12:00 |
08:54:00.68 |
+75:54:44.0 |
HIP 43940 |
19.71 |
| 2026-08-03 00:00 |
08:54:17.69 |
+75:54:36.0 |
HIP 43940 |
19.03 |
| 2026-08-03 12:00 |
08:54:34.71 |
+75:54:28.4 |
HIP 43940 |
18.40 |
| 2026-08-04 00:00 |
08:54:51.71 |
+75:54:21.3 |
HIP 43940 |
17.81 |
| 2026-08-04 12:00 |
08:55:08.72 |
+75:54:14.5 |
HIP 43940 |
17.27 |
| 2026-08-05 00:00 |
08:55:25.72 |
+75:54:08.3 |
HIP 43940 |
16.78 |
| 2026-08-05 12:00 |
08:55:42.71 |
+75:54:02.4 |
HIP 43940 |
16.36 |
| 2026-08-06 00:00 |
08:55:59.70 |
+75:53:57.0 |
HIP 43940 |
16.00 |
| 2026-08-06 12:00 |
08:56:16.68 |
+75:53:52.0 |
HIP 43940 |
15.71 |
| 2026-08-07 00:00 |
08:56:33.65 |
+75:53:47.5 |
HIP 43940 |
15.49 |
| 2026-08-07 12:00 |
08:56:50.62 |
+75:53:43.4 |
HIP 43940 |
15.35 |
| 2026-08-08 00:00 |
08:57:07.57 |
+75:53:39.7 |
HIP 43940 |
15.29 |
| 2026-08-08 12:00 |
08:57:24.51 |
+75:53:36.4 |
HIP 43940 |
15.30 |
| 2026-08-09 00:00 |
08:57:41.45 |
+75:53:33.6 |
HIP 43940 |
15.39 |
| 2026-08-09 12:00 |
08:57:58.37 |
+75:53:31.3 |
HIP 43940 |
15.56 |
| 2026-08-10 00:00 |
08:58:15.27 |
+75:53:29.3 |
HIP 43940 |
15.81 |
| 2026-08-10 12:00 |
08:58:32.17 |
+75:53:27.9 |
HIP 43940 |
16.12 |
| 2026-08-11 00:00 |
08:58:49.04 |
+75:53:26.8 |
HIP 43940 |
16.50 |
| 2026-08-11 12:00 |
08:59:05.91 |
+75:53:26.2 |
HIP 43940 |
16.94 |
| 2026-08-12 00:00 |
08:59:22.75 |
+75:53:26.1 |
HIP 43940 |
17.43 |
| 2026-08-12 12:00 |
08:59:39.58 |
+75:53:26.4 |
HIP 43940 |
17.98 |
| 2026-08-13 00:00 |
08:59:56.39 |
+75:53:27.1 |
HIP 43940 |
18.57 |
| 2026-08-13 12:00 |
09:00:13.18 |
+75:53:28.3 |
HIP 44514 |
19.20 |
| 2026-08-14 00:00 |
09:00:29.96 |
+75:53:29.9 |
HIP 44514 |
18.45 |
| 2026-08-14 12:00 |
09:00:46.71 |
+75:53:32.0 |
HIP 44514 |
17.72 |
| 2026-08-15 00:00 |
09:01:03.44 |
+75:53:34.5 |
HIP 44514 |
17.04 |
| 2026-08-15 12:00 |
09:01:20.14 |
+75:53:37.5 |
HIP 44514 |
16.40 |
| 2026-08-16 00:00 |
09:01:36.82 |
+75:53:40.9 |
HIP 44514 |
15.81 |
| 2026-08-16 12:00 |
09:01:53.48 |
+75:53:44.8 |
HIP 44514 |
15.27 |
| 2026-08-17 00:00 |
09:02:10.11 |
+75:53:49.1 |
HIP 44514 |
14.78 |
| 2026-08-17 12:00 |
09:02:26.72 |
+75:53:53.9 |
HIP 44514 |
14.37 |
| 2026-08-18 00:00 |
09:02:43.30 |
+75:53:59.1 |
HIP 44514 |
14.02 |
| 2026-08-18 12:00 |
09:02:59.85 |
+75:54:04.7 |
HIP 44514 |
13.75 |
| 2026-08-19 00:00 |
09:03:16.38 |
+75:54:10.8 |
HIP 44514 |
13.55 |