| 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) |
| 2026-07-29 00:00 |
16:55:13.59 |
+10:33:36.3 |
HIP 82909 |
27.48 |
| 2026-07-29 12:00 |
16:55:08.60 |
+10:32:31.0 |
HIP 82909 |
27.65 |
| 2026-07-30 00:00 |
16:55:03.67 |
+10:31:25.4 |
HIP 82673 |
26.52 |
| 2026-07-30 12:00 |
16:54:58.80 |
+10:30:19.5 |
HIP 82673 |
24.93 |
| 2026-07-31 00:00 |
16:54:53.98 |
+10:29:13.2 |
HIP 82673 |
23.35 |
| 2026-07-31 12:00 |
16:54:49.23 |
+10:28:06.6 |
HIP 82673 |
21.78 |
| 2026-08-01 00:00 |
16:54:44.53 |
+10:26:59.6 |
HIP 82673 |
20.21 |
| 2026-08-01 12:00 |
16:54:39.90 |
+10:25:52.3 |
HIP 82673 |
18.66 |
| 2026-08-02 00:00 |
16:54:35.32 |
+10:24:44.7 |
HIP 82673 |
17.12 |
| 2026-08-02 12:00 |
16:54:30.81 |
+10:23:36.8 |
HIP 82673 |
15.59 |
| 2026-08-03 00:00 |
16:54:26.36 |
+10:22:28.6 |
HIP 82673 |
14.07 |
| 2026-08-03 12:00 |
16:54:21.96 |
+10:21:20.1 |
HIP 82673 |
12.57 |
| 2026-08-04 00:00 |
16:54:17.63 |
+10:20:11.2 |
HIP 82673 |
11.09 |
| 2026-08-04 12:00 |
16:54:13.36 |
+10:19:02.1 |
HIP 82673 |
9.64 |
| 2026-08-05 00:00 |
16:54:09.16 |
+10:17:52.6 |
HIP 82673 |
8.23 |
| 2026-08-05 12:00 |
16:54:05.01 |
+10:16:42.9 |
HIP 82673 |
6.88 |
| 2026-08-06 00:00 |
16:54:00.93 |
+10:15:32.9 |
HIP 82673 |
5.62 |
| 2026-08-06 12:00 |
16:53:56.91 |
+10:14:22.6 |
HIP 82673 |
4.54 |
| 2026-08-07 00:00 |
16:53:52.95 |
+10:13:12.0 |
HIP 82673 |
3.76 |
| 2026-08-07 12:00 |
16:53:49.06 |
+10:12:01.1 |
HIP 82673 |
3.51 |
| 2026-08-08 00:00 |
16:53:45.23 |
+10:10:50.0 |
HIP 82673 |
3.87 |
| 2026-08-08 12:00 |
16:53:41.46 |
+10:09:38.6 |
HIP 82673 |
4.70 |
| 2026-08-09 00:00 |
16:53:37.75 |
+10:08:26.9 |
HIP 82673 |
5.79 |
| 2026-08-09 12:00 |
16:53:34.11 |
+10:07:15.0 |
HIP 82673 |
7.02 |
| 2026-08-10 00:00 |
16:53:30.54 |
+10:06:02.8 |
HIP 82673 |
8.33 |
| 2026-08-10 12:00 |
16:53:27.03 |
+10:04:50.4 |
HIP 82673 |
9.68 |
| 2026-08-11 00:00 |
16:53:23.58 |
+10:03:37.7 |
HIP 82673 |
11.06 |
| 2026-08-11 12:00 |
16:53:20.20 |
+10:02:24.8 |
HIP 82673 |
12.44 |
| 2026-08-12 00:00 |
16:53:16.88 |
+10:01:11.6 |
HIP 82673 |
13.84 |
| 2026-08-12 12:00 |
16:53:13.63 |
+09:59:58.3 |
HIP 82673 |
15.24 |
| 2026-08-13 00:00 |
16:53:10.44 |
+09:58:44.7 |
HIP 82673 |
16.64 |
| 2026-08-13 12:00 |
16:53:07.32 |
+09:57:30.8 |
HIP 82673 |
18.04 |
| 2026-08-14 00:00 |
16:53:04.26 |
+09:56:16.8 |
HIP 82673 |
19.44 |
| 2026-08-14 12:00 |
16:53:01.27 |
+09:55:02.5 |
HIP 82673 |
20.84 |
| 2026-08-15 00:00 |
16:52:58.35 |
+09:53:48.1 |
HIP 82673 |
22.23 |
| 2026-08-15 12:00 |
16:52:55.49 |
+09:52:33.4 |
HIP 82673 |
23.62 |
| 2026-08-16 00:00 |
16:52:52.70 |
+09:51:18.6 |
HIP 82673 |
25.00 |
| 2026-08-16 12:00 |
16:52:49.97 |
+09:50:03.6 |
HIP 82673 |
26.39 |
| 2026-08-17 00:00 |
16:52:47.31 |
+09:48:48.3 |
HIP 82456 |
25.97 |
| 2026-08-17 12:00 |
16:52:44.72 |
+09:47:32.9 |
HIP 82456 |
25.57 |
| 2026-08-18 00:00 |
16:52:42.19 |
+09:46:17.3 |
HIP 82456 |
25.25 |
| 2026-08-18 12:00 |
16:52:39.73 |
+09:45:01.6 |
HIP 82456 |
25.02 |
| 2026-08-19 00:00 |
16:52:37.33 |
+09:43:45.7 |
HIP 82456 |
24.89 |