| 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 · University of Arizona 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) |
| 2026-09-20 00:00 |
16:52:20.70 |
+08:20:20.4 |
HIP 82631 |
23.18 |
| 2026-09-20 12:00 |
16:52:22.52 |
+08:19:03.0 |
HIP 82631 |
23.76 |
| 2026-09-21 00:00 |
16:52:24.39 |
+08:17:45.6 |
HIP 82631 |
24.39 |
| 2026-09-21 12:00 |
16:52:26.33 |
+08:16:28.4 |
HIP 82631 |
25.07 |
| 2026-09-22 00:00 |
16:52:28.32 |
+08:15:11.3 |
HIP 82631 |
25.80 |
| 2026-09-22 12:00 |
16:52:30.38 |
+08:13:54.3 |
HIP 82680 |
25.95 |
| 2026-09-23 00:00 |
16:52:32.49 |
+08:12:37.4 |
HIP 82680 |
26.12 |
| 2026-09-23 12:00 |
16:52:34.66 |
+08:11:20.7 |
HIP 82680 |
26.35 |
| 2026-09-24 00:00 |
16:52:36.89 |
+08:10:04.1 |
HIP 82680 |
26.64 |
| 2026-09-24 12:00 |
16:52:39.18 |
+08:08:47.7 |
HIP 82680 |
26.98 |
| 2026-09-25 00:00 |
16:52:41.53 |
+08:07:31.4 |
HIP 82680 |
27.37 |
| 2026-09-25 12:00 |
16:52:43.94 |
+08:06:15.2 |
HIP 82680 |
27.82 |
| 2026-09-26 00:00 |
16:52:46.40 |
+08:04:59.2 |
HIP 82680 |
28.32 |
| 2026-09-26 12:00 |
16:52:48.92 |
+08:03:43.3 |
HIP 82680 |
28.87 |
| 2026-09-27 00:00 |
16:52:51.49 |
+08:02:27.6 |
HIP 82680 |
29.47 |
| 2026-09-27 12:00 |
16:52:54.13 |
+08:01:12.1 |
HIP 82680 |
30.11 |
| 2026-09-28 00:00 |
16:52:56.82 |
+07:59:56.7 |
HIP 82614 |
29.91 |
| 2026-09-28 12:00 |
16:52:59.56 |
+07:58:41.5 |
HIP 82614 |
28.55 |
| 2026-09-29 00:00 |
16:53:02.37 |
+07:57:26.4 |
HIP 82614 |
27.20 |
| 2026-09-29 12:00 |
16:53:05.23 |
+07:56:11.5 |
HIP 82614 |
25.86 |
| 2026-09-30 00:00 |
16:53:08.14 |
+07:54:56.8 |
HIP 82614 |
24.53 |
| 2026-09-30 12:00 |
16:53:11.11 |
+07:53:42.3 |
HIP 82614 |
23.21 |
| 2026-10-01 00:00 |
16:53:14.13 |
+07:52:27.9 |
HIP 82614 |
21.92 |
| 2026-10-01 12:00 |
16:53:17.21 |
+07:51:13.8 |
HIP 82614 |
20.64 |
| 2026-10-02 00:00 |
16:53:20.35 |
+07:49:59.8 |
HIP 82614 |
19.40 |
| 2026-10-02 12:00 |
16:53:23.54 |
+07:48:46.0 |
HIP 82614 |
18.19 |
| 2026-10-03 00:00 |
16:53:26.78 |
+07:47:32.4 |
HIP 82614 |
17.02 |
| 2026-10-03 12:00 |
16:53:30.08 |
+07:46:19.0 |
HIP 82614 |
15.91 |
| 2026-10-04 00:00 |
16:53:33.43 |
+07:45:05.8 |
HIP 82614 |
14.87 |
| 2026-10-04 12:00 |
16:53:36.83 |
+07:43:52.8 |
HIP 82614 |
13.92 |
| 2026-10-05 00:00 |
16:53:40.29 |
+07:42:40.0 |
HIP 82614 |
13.07 |
| 2026-10-05 12:00 |
16:53:43.80 |
+07:41:27.4 |
HIP 82614 |
12.35 |
| 2026-10-06 00:00 |
16:53:47.36 |
+07:40:15.1 |
HIP 82614 |
11.78 |
| 2026-10-06 12:00 |
16:53:50.97 |
+07:39:02.9 |
HIP 82614 |
11.40 |
| 2026-10-07 00:00 |
16:53:54.64 |
+07:37:51.0 |
HIP 82614 |
11.22 |
| 2026-10-07 12:00 |
16:53:58.36 |
+07:36:39.3 |
HIP 82614 |
11.25 |
| 2026-10-08 00:00 |
16:54:02.13 |
+07:35:27.8 |
HIP 82614 |
11.50 |
| 2026-10-08 12:00 |
16:54:05.95 |
+07:34:16.6 |
HIP 82614 |
11.95 |
| 2026-10-09 00:00 |
16:54:09.82 |
+07:33:05.6 |
HIP 82614 |
12.58 |
| 2026-10-09 12:00 |
16:54:13.74 |
+07:31:54.8 |
HIP 82733 |
12.84 |
| 2026-10-10 00:00 |
16:54:17.72 |
+07:30:44.3 |
HIP 82733 |
11.35 |
| 2026-10-10 12:00 |
16:54:21.74 |
+07:29:34.0 |
HIP 82733 |
9.88 |
| 2026-10-11 00:00 |
16:54:25.81 |
+07:28:23.9 |
HIP 82733 |
8.43 |