C/2017 E5 (Lemmon)
| 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 |
1.000 |
| 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) |
| 2026-02-03 00:00 |
09:05:00.39 |
+79:50:28.9 |
HIP 45100 |
16.60 |
| 2026-02-03 12:00 |
09:04:30.19 |
+79:50:40.8 |
HIP 45100 |
17.93 |
| 2026-02-04 00:00 |
09:04:00.00 |
+79:50:51.9 |
HIP 45100 |
19.27 |
| 2026-02-04 12:00 |
09:03:29.80 |
+79:51:02.2 |
HIP 45100 |
20.60 |
| 2026-02-05 00:00 |
09:02:59.60 |
+79:51:11.7 |
HIP 43830 |
21.33 |
| 2026-02-05 12:00 |
09:02:29.41 |
+79:51:20.5 |
HIP 43830 |
20.17 |
| 2026-02-06 00:00 |
09:01:59.24 |
+79:51:28.5 |
HIP 43830 |
19.02 |
| 2026-02-06 12:00 |
09:01:29.08 |
+79:51:35.7 |
HIP 43830 |
17.90 |
| 2026-02-07 00:00 |
09:00:58.94 |
+79:51:42.1 |
HIP 43830 |
16.80 |
| 2026-02-07 12:00 |
09:00:28.82 |
+79:51:47.7 |
HIP 43830 |
15.74 |
| 2026-02-08 00:00 |
08:59:58.73 |
+79:51:52.6 |
HIP 43830 |
14.72 |
| 2026-02-08 12:00 |
08:59:28.67 |
+79:51:56.7 |
HIP 43830 |
13.74 |
| 2026-02-09 00:00 |
08:58:58.64 |
+79:52:00.0 |
HIP 43830 |
12.81 |
| 2026-02-09 12:00 |
08:58:28.66 |
+79:52:02.5 |
HIP 43830 |
11.96 |
| 2026-02-10 00:00 |
08:57:58.72 |
+79:52:04.3 |
HIP 43830 |
11.19 |
| 2026-02-10 12:00 |
08:57:28.82 |
+79:52:05.3 |
HIP 43830 |
10.52 |
| 2026-02-11 00:00 |
08:56:58.98 |
+79:52:05.5 |
HIP 43830 |
9.97 |
| 2026-02-11 12:00 |
08:56:29.19 |
+79:52:04.9 |
HIP 43830 |
9.56 |
| 2026-02-12 00:00 |
08:55:59.47 |
+79:52:03.6 |
HIP 43830 |
9.31 |
| 2026-02-12 12:00 |
08:55:29.80 |
+79:52:01.5 |
HIP 43830 |
9.23 |
| 2026-02-13 00:00 |
08:55:00.21 |
+79:51:58.6 |
HIP 43830 |
9.33 |
| 2026-02-13 12:00 |
08:54:30.68 |
+79:51:55.0 |
HIP 43830 |
9.59 |
| 2026-02-14 00:00 |
08:54:01.23 |
+79:51:50.6 |
HIP 43830 |
10.00 |
| 2026-02-14 12:00 |
08:53:31.86 |
+79:51:45.4 |
HIP 43478 |
10.46 |
| 2026-02-15 00:00 |
08:53:02.57 |
+79:51:39.5 |
HIP 43478 |
9.91 |
| 2026-02-15 12:00 |
08:52:33.37 |
+79:51:32.8 |
HIP 43478 |
9.52 |
| 2026-02-16 00:00 |
08:52:04.26 |
+79:51:25.4 |
HIP 43478 |
9.30 |
| 2026-02-16 12:00 |
08:51:35.25 |
+79:51:17.2 |
HIP 43478 |
9.26 |
| 2026-02-17 00:00 |
08:51:06.33 |
+79:51:08.3 |
HIP 43478 |
9.41 |
| 2026-02-17 12:00 |
08:50:37.52 |
+79:50:58.6 |
HIP 43478 |
9.74 |
| 2026-02-18 00:00 |
08:50:08.81 |
+79:50:48.2 |
HIP 43478 |
10.23 |
| 2026-02-18 12:00 |
08:49:40.22 |
+79:50:37.0 |
HIP 43478 |
10.86 |
| 2026-02-19 00:00 |
08:49:11.73 |
+79:50:25.1 |
HIP 43478 |
11.59 |
| 2026-02-19 12:00 |
08:48:43.37 |
+79:50:12.5 |
HIP 43478 |
12.42 |
| 2026-02-20 00:00 |
08:48:15.12 |
+79:49:59.1 |
HIP 43478 |
13.33 |
| 2026-02-20 12:00 |
08:47:47.00 |
+79:49:45.0 |
HIP 43478 |
14.29 |
| 2026-02-21 00:00 |
08:47:19.01 |
+79:49:30.2 |
HIP 43478 |
15.30 |
| 2026-02-21 12:00 |
08:46:51.15 |
+79:49:14.7 |
HIP 43478 |
16.35 |
| 2026-02-22 00:00 |
08:46:23.42 |
+79:48:58.4 |
HIP 43478 |
17.43 |
| 2026-02-22 12:00 |
08:45:55.83 |
+79:48:41.5 |
HIP 43478 |
18.53 |
| 2026-02-23 00:00 |
08:45:28.39 |
+79:48:23.8 |
HIP 43478 |
19.66 |
| 2026-02-23 12:00 |
08:45:01.08 |
+79:48:05.5 |
HIP 43478 |
20.80 |
| 2026-02-24 00:00 |
08:44:33.93 |
+79:47:46.4 |
HIP 43478 |
21.95 |