| Parameter |
Value |
| Designation |
C/2020 W5 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2020-11-30T01:54:40.083840Z |
| Orbit solution date (soln_date, UTC) |
2025-01-10T09:12:15Z |
| Obs used |
55 |
| NEO |
- |
| M1 |
14.200 |
| K1 |
10.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2020-11-20T05:24:13.046400Z |
| Discovery magnitude (MPC) |
21.61 G |
| Discovery observatory (MPC) |
G96 · Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2020-11-30.0000000 |
| e |
1.00164978 |
| q (au) |
3.364485 |
| a (au) |
-2039.359232 |
| i (deg) |
88.594700 |
| Ω (om, deg) |
75.516670 |
| ω (w, deg) |
24.475527 |
| M (ma, deg) |
-0.000001 |
Magnitude
Scatter + Global Linear
$$
M_a = (16.215 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
16.215 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.960 |
| 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) |
| 2026-05-12 00:00 |
17:14:59.94 |
+11:40:05.0 |
HIP 84308 |
25.36 |
| 2026-05-12 12:00 |
17:14:52.30 |
+11:40:23.3 |
HIP 84308 |
24.25 |
| 2026-05-13 00:00 |
17:14:44.63 |
+11:40:41.2 |
HIP 84308 |
23.24 |
| 2026-05-13 12:00 |
17:14:36.92 |
+11:40:58.5 |
HIP 84308 |
22.36 |
| 2026-05-14 00:00 |
17:14:29.18 |
+11:41:15.3 |
HIP 84308 |
21.61 |
| 2026-05-14 12:00 |
17:14:21.40 |
+11:41:31.6 |
HIP 84308 |
21.02 |
| 2026-05-15 00:00 |
17:14:13.59 |
+11:41:47.4 |
HIP 84308 |
20.61 |
| 2026-05-15 12:00 |
17:14:05.75 |
+11:42:02.6 |
HIP 84308 |
20.37 |
| 2026-05-16 00:00 |
17:13:57.88 |
+11:42:17.3 |
HIP 84308 |
20.33 |
| 2026-05-16 12:00 |
17:13:49.97 |
+11:42:31.4 |
HIP 84193 |
19.18 |
| 2026-05-17 00:00 |
17:13:42.04 |
+11:42:45.0 |
HIP 84193 |
17.46 |
| 2026-05-17 12:00 |
17:13:34.08 |
+11:42:58.1 |
HIP 84193 |
15.79 |
| 2026-05-18 00:00 |
17:13:26.09 |
+11:43:10.6 |
HIP 84193 |
14.19 |
| 2026-05-18 12:00 |
17:13:18.07 |
+11:43:22.5 |
HIP 84193 |
12.68 |
| 2026-05-19 00:00 |
17:13:10.03 |
+11:43:33.9 |
HIP 84193 |
11.30 |
| 2026-05-19 12:00 |
17:13:01.96 |
+11:43:44.8 |
HIP 84193 |
10.10 |
| 2026-05-20 00:00 |
17:12:53.86 |
+11:43:55.1 |
HIP 84193 |
9.18 |
| 2026-05-20 12:00 |
17:12:45.74 |
+11:44:04.8 |
HIP 84193 |
8.61 |
| 2026-05-21 00:00 |
17:12:37.59 |
+11:44:14.0 |
HIP 84193 |
8.48 |
| 2026-05-21 12:00 |
17:12:29.43 |
+11:44:22.6 |
HIP 84193 |
8.80 |
| 2026-05-22 00:00 |
17:12:21.24 |
+11:44:30.6 |
HIP 84193 |
9.54 |
| 2026-05-22 12:00 |
17:12:13.02 |
+11:44:38.0 |
HIP 84193 |
10.60 |
| 2026-05-23 00:00 |
17:12:04.79 |
+11:44:44.9 |
HIP 84193 |
11.91 |
| 2026-05-23 12:00 |
17:11:56.54 |
+11:44:51.2 |
HIP 84193 |
13.39 |
| 2026-05-24 00:00 |
17:11:48.27 |
+11:44:57.0 |
HIP 84050 |
14.74 |
| 2026-05-24 12:00 |
17:11:39.98 |
+11:45:02.2 |
HIP 84050 |
13.20 |
| 2026-05-25 00:00 |
17:11:31.67 |
+11:45:06.7 |
HIP 84050 |
11.80 |
| 2026-05-25 12:00 |
17:11:23.34 |
+11:45:10.8 |
HIP 84050 |
10.60 |
| 2026-05-26 00:00 |
17:11:15.00 |
+11:45:14.2 |
HIP 84050 |
9.67 |
| 2026-05-26 12:00 |
17:11:06.64 |
+11:45:17.0 |
HIP 84050 |
9.11 |
| 2026-05-27 00:00 |
17:10:58.26 |
+11:45:19.3 |
HIP 84050 |
8.97 |
| 2026-05-27 12:00 |
17:10:49.87 |
+11:45:21.0 |
HIP 84050 |
9.29 |
| 2026-05-28 00:00 |
17:10:41.47 |
+11:45:22.1 |
HIP 84050 |
10.02 |
| 2026-05-28 12:00 |
17:10:33.05 |
+11:45:22.6 |
HIP 84050 |
11.09 |
| 2026-05-29 00:00 |
17:10:24.63 |
+11:45:22.5 |
HIP 84050 |
12.40 |
| 2026-05-29 12:00 |
17:10:16.19 |
+11:45:21.8 |
HIP 84050 |
13.89 |
| 2026-05-30 00:00 |
17:10:07.73 |
+11:45:20.6 |
HIP 84050 |
15.51 |
| 2026-05-30 12:00 |
17:09:59.27 |
+11:45:18.7 |
HIP 84050 |
17.23 |
| 2026-05-31 00:00 |
17:09:50.80 |
+11:45:16.3 |
HIP 84050 |
19.01 |
| 2026-05-31 12:00 |
17:09:42.32 |
+11:45:13.3 |
HIP 84050 |
20.84 |
| 2026-06-01 00:00 |
17:09:33.83 |
+11:45:09.6 |
HIP 84050 |
22.72 |
| 2026-06-01 12:00 |
17:09:25.33 |
+11:45:05.4 |
HIP 84050 |
24.62 |
| 2026-06-02 00:00 |
17:09:16.83 |
+11:45:00.6 |
HIP 84050 |
26.55 |