| 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 · University of Arizona 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) |
| 2026-07-29 00:00 |
04:59:20.36 |
-36:16:31.1 |
HIP 23224 |
21.86 |
| 2026-07-29 12:00 |
04:59:25.09 |
-36:17:35.0 |
HIP 23224 |
20.57 |
| 2026-07-30 00:00 |
04:59:29.76 |
-36:18:39.6 |
HIP 23224 |
19.30 |
| 2026-07-30 12:00 |
04:59:34.38 |
-36:19:44.6 |
HIP 23224 |
18.05 |
| 2026-07-31 00:00 |
04:59:38.93 |
-36:20:50.3 |
HIP 23224 |
16.82 |
| 2026-07-31 12:00 |
04:59:43.42 |
-36:21:56.5 |
HIP 23224 |
15.61 |
| 2026-08-01 00:00 |
04:59:47.86 |
-36:23:03.3 |
HIP 23224 |
14.43 |
| 2026-08-01 12:00 |
04:59:52.23 |
-36:24:10.6 |
HIP 23224 |
13.29 |
| 2026-08-02 00:00 |
04:59:56.54 |
-36:25:18.4 |
HIP 23224 |
12.20 |
| 2026-08-02 12:00 |
05:00:00.79 |
-36:26:26.8 |
HIP 23224 |
11.18 |
| 2026-08-03 00:00 |
05:00:04.98 |
-36:27:35.8 |
HIP 23224 |
10.24 |
| 2026-08-03 12:00 |
05:00:09.11 |
-36:28:45.3 |
HIP 23224 |
9.41 |
| 2026-08-04 00:00 |
05:00:13.18 |
-36:29:55.3 |
HIP 23224 |
8.72 |
| 2026-08-04 12:00 |
05:00:17.18 |
-36:31:05.8 |
HIP 23224 |
8.21 |
| 2026-08-05 00:00 |
05:00:21.12 |
-36:32:16.9 |
HIP 23224 |
7.91 |
| 2026-08-05 12:00 |
05:00:24.99 |
-36:33:28.5 |
HIP 23224 |
7.84 |
| 2026-08-06 00:00 |
05:00:28.80 |
-36:34:40.6 |
HIP 23224 |
8.01 |
| 2026-08-06 12:00 |
05:00:32.55 |
-36:35:53.2 |
HIP 23224 |
8.41 |
| 2026-08-07 00:00 |
05:00:36.23 |
-36:37:06.3 |
HIP 23224 |
9.00 |
| 2026-08-07 12:00 |
05:00:39.84 |
-36:38:19.9 |
HIP 23224 |
9.76 |
| 2026-08-08 00:00 |
05:00:43.39 |
-36:39:34.0 |
HIP 23224 |
10.64 |
| 2026-08-08 12:00 |
05:00:46.88 |
-36:40:48.6 |
HIP 23224 |
11.62 |
| 2026-08-09 00:00 |
05:00:50.29 |
-36:42:03.7 |
HIP 23224 |
12.67 |
| 2026-08-09 12:00 |
05:00:53.64 |
-36:43:19.3 |
HIP 23224 |
13.79 |
| 2026-08-10 00:00 |
05:00:56.92 |
-36:44:35.3 |
HIP 23224 |
14.94 |
| 2026-08-10 12:00 |
05:01:00.13 |
-36:45:51.8 |
HIP 23224 |
16.14 |
| 2026-08-11 00:00 |
05:01:03.27 |
-36:47:08.8 |
HIP 23412 |
15.43 |
| 2026-08-11 12:00 |
05:01:06.35 |
-36:48:26.3 |
HIP 23412 |
14.06 |
| 2026-08-12 00:00 |
05:01:09.35 |
-36:49:44.2 |
HIP 23412 |
12.71 |
| 2026-08-12 12:00 |
05:01:12.28 |
-36:51:02.5 |
HIP 23412 |
11.38 |
| 2026-08-13 00:00 |
05:01:15.15 |
-36:52:21.3 |
HIP 23412 |
10.09 |
| 2026-08-13 12:00 |
05:01:17.94 |
-36:53:40.5 |
HIP 23412 |
8.85 |
| 2026-08-14 00:00 |
05:01:20.66 |
-36:55:00.2 |
HIP 23412 |
7.69 |
| 2026-08-14 12:00 |
05:01:23.31 |
-36:56:20.2 |
HIP 23412 |
6.65 |
| 2026-08-15 00:00 |
05:01:25.88 |
-36:57:40.7 |
HIP 23412 |
5.79 |
| 2026-08-15 12:00 |
05:01:28.39 |
-36:59:01.6 |
HIP 23412 |
5.20 |
| 2026-08-16 00:00 |
05:01:30.82 |
-37:00:22.9 |
HIP 23412 |
5.00 |
| 2026-08-16 12:00 |
05:01:33.17 |
-37:01:44.6 |
HIP 23412 |
5.21 |
| 2026-08-17 00:00 |
05:01:35.46 |
-37:03:06.7 |
HIP 23412 |
5.80 |
| 2026-08-17 12:00 |
05:01:37.67 |
-37:04:29.2 |
HIP 23412 |
6.67 |
| 2026-08-18 00:00 |
05:01:39.80 |
-37:05:52.1 |
HIP 23412 |
7.73 |
| 2026-08-18 12:00 |
05:01:41.87 |
-37:07:15.3 |
HIP 23412 |
8.91 |
| 2026-08-19 00:00 |
05:01:43.85 |
-37:08:38.9 |
HIP 23412 |
10.16 |