| Parameter |
Value |
| Designation |
C/2020 B2 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2020-01-26T06:53:39.419520Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:34:04Z |
| Obs used |
106 |
| NEO |
- |
| M1 |
17.200 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2020-02-04.0000000 |
| e |
0.95922180 |
| q (au) |
2.768047 |
| a (au) |
67.880568 |
| i (deg) |
55.704138 |
| Ω (om, deg) |
354.338868 |
| ω (w, deg) |
143.629671 |
| M (ma, deg) |
0.015355 |
Magnitude
Scatter + Global Linear
$$
M_a = (16.433 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
16.433 |
| n |
2.000 |
| gf |
0.999 |
| gb |
-1.000 |
| k |
0.998 |
| 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 |
18:41:35.38 |
-78:32:19.8 |
HIP 92383 |
25.15 |
| 2026-09-20 12:00 |
18:41:33.56 |
-78:30:51.7 |
HIP 92383 |
25.78 |
| 2026-09-21 00:00 |
18:41:32.04 |
-78:29:23.5 |
HIP 91795 |
25.83 |
| 2026-09-21 12:00 |
18:41:30.82 |
-78:27:55.2 |
HIP 91795 |
24.40 |
| 2026-09-22 00:00 |
18:41:29.89 |
-78:26:26.8 |
HIP 91795 |
22.97 |
| 2026-09-22 12:00 |
18:41:29.27 |
-78:24:58.3 |
HIP 91795 |
21.53 |
| 2026-09-23 00:00 |
18:41:28.93 |
-78:23:29.7 |
HIP 91795 |
20.10 |
| 2026-09-23 12:00 |
18:41:28.89 |
-78:22:01.0 |
HIP 91795 |
18.67 |
| 2026-09-24 00:00 |
18:41:29.15 |
-78:20:32.2 |
HIP 91795 |
17.24 |
| 2026-09-24 12:00 |
18:41:29.69 |
-78:19:03.4 |
HIP 91795 |
15.82 |
| 2026-09-25 00:00 |
18:41:30.52 |
-78:17:34.5 |
HIP 91795 |
14.40 |
| 2026-09-25 12:00 |
18:41:31.63 |
-78:16:05.5 |
HIP 91795 |
12.99 |
| 2026-09-26 00:00 |
18:41:33.03 |
-78:14:36.5 |
HIP 91795 |
11.60 |
| 2026-09-26 12:00 |
18:41:34.71 |
-78:13:07.4 |
HIP 91795 |
10.21 |
| 2026-09-27 00:00 |
18:41:36.67 |
-78:11:38.3 |
HIP 91795 |
8.86 |
| 2026-09-27 12:00 |
18:41:38.90 |
-78:10:09.2 |
HIP 91795 |
7.55 |
| 2026-09-28 00:00 |
18:41:41.42 |
-78:08:40.0 |
HIP 91795 |
6.31 |
| 2026-09-28 12:00 |
18:41:44.20 |
-78:07:10.8 |
HIP 91795 |
5.18 |
| 2026-09-29 00:00 |
18:41:47.27 |
-78:05:41.6 |
HIP 91795 |
4.28 |
| 2026-09-29 12:00 |
18:41:50.60 |
-78:04:12.4 |
HIP 91795 |
3.76 |
| 2026-09-30 00:00 |
18:41:54.20 |
-78:02:43.1 |
HIP 91795 |
3.78 |
| 2026-09-30 12:00 |
18:41:58.07 |
-78:01:13.9 |
HIP 91795 |
4.35 |
| 2026-10-01 00:00 |
18:42:02.21 |
-77:59:44.6 |
HIP 91795 |
5.28 |
| 2026-10-01 12:00 |
18:42:06.61 |
-77:58:15.4 |
HIP 91756 |
3.87 |
| 2026-10-02 00:00 |
18:42:11.27 |
-77:56:46.2 |
HIP 91756 |
2.46 |
| 2026-10-02 12:00 |
18:42:16.20 |
-77:55:16.9 |
HIP 91756 |
1.27 |
| 2026-10-03 00:00 |
18:42:21.38 |
-77:53:47.7 |
HIP 91756 |
1.32 |
| 2026-10-03 12:00 |
18:42:26.83 |
-77:52:18.6 |
HIP 91756 |
2.53 |
| 2026-10-04 00:00 |
18:42:32.53 |
-77:50:49.4 |
HIP 91756 |
3.95 |
| 2026-10-04 12:00 |
18:42:38.48 |
-77:49:20.3 |
HIP 91756 |
5.43 |
| 2026-10-05 00:00 |
18:42:44.69 |
-77:47:51.3 |
HIP 91756 |
6.92 |
| 2026-10-05 12:00 |
18:42:51.15 |
-77:46:22.2 |
HIP 91756 |
8.42 |
| 2026-10-06 00:00 |
18:42:57.86 |
-77:44:53.3 |
HIP 91756 |
9.93 |
| 2026-10-06 12:00 |
18:43:04.81 |
-77:43:24.4 |
HIP 91756 |
11.44 |
| 2026-10-07 00:00 |
18:43:12.02 |
-77:41:55.5 |
HIP 91756 |
12.96 |
| 2026-10-07 12:00 |
18:43:19.47 |
-77:40:26.7 |
HIP 91756 |
14.48 |
| 2026-10-08 00:00 |
18:43:27.16 |
-77:38:58.0 |
HIP 91756 |
16.01 |
| 2026-10-08 12:00 |
18:43:35.09 |
-77:37:29.4 |
HIP 91756 |
17.53 |
| 2026-10-09 00:00 |
18:43:43.27 |
-77:36:00.8 |
HIP 91756 |
19.06 |
| 2026-10-09 12:00 |
18:43:51.68 |
-77:34:32.3 |
HIP 91932 |
18.15 |
| 2026-10-10 00:00 |
18:44:00.33 |
-77:33:04.0 |
HIP 91932 |
16.63 |
| 2026-10-10 12:00 |
18:44:09.21 |
-77:31:35.7 |
HIP 91932 |
15.13 |
| 2026-10-11 00:00 |
18:44:18.32 |
-77:30:07.5 |
HIP 91932 |
13.63 |