C/2020 S8 (Lemmon)
| Parameter |
Value |
| Designation |
C/2020 S8 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-04-10T22:18:20.384640Z |
| Orbit solution date (soln_date, UTC) |
2021-08-06T00:42:41Z |
| Obs used |
591 |
| NEO |
- |
| M1 |
9.900 |
| K1 |
16.500 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2020-09-18T02:54:34.272000Z |
| Discovery magnitude (MPC) |
20.10 G |
| Discovery observatory (MPC) |
G96 · Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-03-21.0000000 |
| e |
0.99139921 |
| q (au) |
2.363839 |
| a (au) |
274.839865 |
| i (deg) |
108.517979 |
| Ω (om, deg) |
24.051990 |
| ω (w, deg) |
160.334070 |
| M (ma, deg) |
359.995473 |
Magnitude
Scatter + Global Linear
$$
M_a = (10.125 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
10.125 |
| n |
6.000 |
| gf |
0.999 |
| gb |
-0.807 |
| k |
0.994 |
| 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 |
04:33:12.23 |
-41:30:18.8 |
HIP 21368 |
21.30 |
| 2026-02-03 12:00 |
04:33:05.98 |
-41:28:24.9 |
HIP 21368 |
22.83 |
| 2026-02-04 00:00 |
04:32:59.83 |
-41:26:30.7 |
HIP 21330 |
22.77 |
| 2026-02-04 12:00 |
04:32:53.79 |
-41:24:36.0 |
HIP 21330 |
22.76 |
| 2026-02-05 00:00 |
04:32:47.84 |
-41:22:40.9 |
HIP 21330 |
22.94 |
| 2026-02-05 12:00 |
04:32:42.00 |
-41:20:45.4 |
HIP 21063 |
22.88 |
| 2026-02-06 00:00 |
04:32:36.27 |
-41:18:49.6 |
HIP 21063 |
21.09 |
| 2026-02-06 12:00 |
04:32:30.63 |
-41:16:53.4 |
HIP 21063 |
19.40 |
| 2026-02-07 00:00 |
04:32:25.09 |
-41:14:56.8 |
HIP 21063 |
17.84 |
| 2026-02-07 12:00 |
04:32:19.66 |
-41:13:00.0 |
HIP 21063 |
16.44 |
| 2026-02-08 00:00 |
04:32:14.33 |
-41:11:02.7 |
HIP 21063 |
15.26 |
| 2026-02-08 12:00 |
04:32:09.11 |
-41:09:05.1 |
HIP 21063 |
14.33 |
| 2026-02-09 00:00 |
04:32:03.98 |
-41:07:07.2 |
HIP 21063 |
13.71 |
| 2026-02-09 12:00 |
04:31:58.96 |
-41:05:09.0 |
HIP 21063 |
13.45 |
| 2026-02-10 00:00 |
04:31:54.05 |
-41:03:10.5 |
HIP 21063 |
13.56 |
| 2026-02-10 12:00 |
04:31:49.23 |
-41:01:11.7 |
HIP 21063 |
14.02 |
| 2026-02-11 00:00 |
04:31:44.52 |
-40:59:12.6 |
HIP 21063 |
14.81 |
| 2026-02-11 12:00 |
04:31:39.91 |
-40:57:13.3 |
HIP 21063 |
15.88 |
| 2026-02-12 00:00 |
04:31:35.40 |
-40:55:13.7 |
HIP 21063 |
17.17 |
| 2026-02-12 12:00 |
04:31:31.00 |
-40:53:13.8 |
HIP 21063 |
18.63 |
| 2026-02-13 00:00 |
04:31:26.70 |
-40:51:13.7 |
HIP 21063 |
20.23 |
| 2026-02-13 12:00 |
04:31:22.50 |
-40:49:13.4 |
HIP 21063 |
21.93 |
| 2026-02-14 00:00 |
04:31:18.40 |
-40:47:12.8 |
HIP 21063 |
23.72 |
| 2026-02-14 12:00 |
04:31:14.41 |
-40:45:12.0 |
HIP 21035 |
22.65 |
| 2026-02-15 00:00 |
04:31:10.52 |
-40:43:11.0 |
HIP 21035 |
20.50 |
| 2026-02-15 12:00 |
04:31:06.73 |
-40:41:09.8 |
HIP 21035 |
18.36 |
| 2026-02-16 00:00 |
04:31:03.05 |
-40:39:08.5 |
HIP 21035 |
16.22 |
| 2026-02-16 12:00 |
04:30:59.47 |
-40:37:06.9 |
HIP 21035 |
14.08 |
| 2026-02-17 00:00 |
04:30:55.99 |
-40:35:05.2 |
HIP 21035 |
11.95 |
| 2026-02-17 12:00 |
04:30:52.61 |
-40:33:03.4 |
HIP 21035 |
9.82 |
| 2026-02-18 00:00 |
04:30:49.33 |
-40:31:01.3 |
HIP 21035 |
7.70 |
| 2026-02-18 12:00 |
04:30:46.16 |
-40:28:59.2 |
HIP 21035 |
5.57 |
| 2026-02-19 00:00 |
04:30:43.08 |
-40:26:56.9 |
HIP 21035 |
3.46 |
| 2026-02-19 12:00 |
04:30:40.11 |
-40:24:54.5 |
HIP 21035 |
1.36 |
| 2026-02-20 00:00 |
04:30:37.24 |
-40:22:52.0 |
HIP 21035 |
0.85 |
| 2026-02-20 12:00 |
04:30:34.48 |
-40:20:49.4 |
HIP 21035 |
2.92 |
| 2026-02-21 00:00 |
04:30:31.81 |
-40:18:46.7 |
HIP 21035 |
5.02 |
| 2026-02-21 12:00 |
04:30:29.24 |
-40:16:44.0 |
HIP 21030 |
3.72 |
| 2026-02-22 00:00 |
04:30:26.77 |
-40:14:41.1 |
HIP 21030 |
2.04 |
| 2026-02-22 12:00 |
04:30:24.41 |
-40:12:38.2 |
HIP 21030 |
1.81 |
| 2026-02-23 00:00 |
04:30:22.14 |
-40:10:35.3 |
HIP 21030 |
3.33 |
| 2026-02-23 12:00 |
04:30:19.97 |
-40:08:32.3 |
HIP 21030 |
5.26 |
| 2026-02-24 00:00 |
04:30:17.91 |
-40:06:29.3 |
HIP 21030 |
7.27 |