| 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) |
| 2026-05-12 00:00 |
20:28:48.65 |
-78:44:57.1 |
HIP 100891 |
4.07 |
| 2026-05-12 12:00 |
20:28:42.24 |
-78:46:22.0 |
HIP 100891 |
3.87 |
| 2026-05-13 00:00 |
20:28:35.51 |
-78:47:46.8 |
HIP 100891 |
4.19 |
| 2026-05-13 12:00 |
20:28:28.44 |
-78:49:11.5 |
HIP 100891 |
4.92 |
| 2026-05-14 00:00 |
20:28:21.04 |
-78:50:36.0 |
HIP 100891 |
5.91 |
| 2026-05-14 12:00 |
20:28:13.30 |
-78:52:00.4 |
HIP 101137 |
5.75 |
| 2026-05-15 00:00 |
20:28:05.24 |
-78:53:24.6 |
HIP 101137 |
5.70 |
| 2026-05-15 12:00 |
20:27:56.83 |
-78:54:48.7 |
HIP 101137 |
6.03 |
| 2026-05-16 00:00 |
20:27:48.09 |
-78:56:12.6 |
HIP 101137 |
6.69 |
| 2026-05-16 12:00 |
20:27:39.01 |
-78:57:36.3 |
HIP 101137 |
7.58 |
| 2026-05-17 00:00 |
20:27:29.59 |
-78:58:59.8 |
HIP 101137 |
8.64 |
| 2026-05-17 12:00 |
20:27:19.83 |
-79:00:23.1 |
HIP 101137 |
9.81 |
| 2026-05-18 00:00 |
20:27:09.73 |
-79:01:46.2 |
HIP 100594 |
9.38 |
| 2026-05-18 12:00 |
20:26:59.29 |
-79:03:09.1 |
HIP 100594 |
8.79 |
| 2026-05-19 00:00 |
20:26:48.51 |
-79:04:31.8 |
HIP 100594 |
8.40 |
| 2026-05-19 12:00 |
20:26:37.38 |
-79:05:54.2 |
HIP 100594 |
8.24 |
| 2026-05-20 00:00 |
20:26:25.91 |
-79:07:16.4 |
HIP 100594 |
8.33 |
| 2026-05-20 12:00 |
20:26:14.10 |
-79:08:38.3 |
HIP 100594 |
8.66 |
| 2026-05-21 00:00 |
20:26:01.94 |
-79:10:00.0 |
HIP 100594 |
9.20 |
| 2026-05-21 12:00 |
20:25:49.44 |
-79:11:21.3 |
HIP 100594 |
9.92 |
| 2026-05-22 00:00 |
20:25:36.60 |
-79:12:42.3 |
HIP 100594 |
10.79 |
| 2026-05-22 12:00 |
20:25:23.41 |
-79:14:03.1 |
HIP 100913 |
11.38 |
| 2026-05-23 00:00 |
20:25:09.87 |
-79:15:23.6 |
HIP 100913 |
10.67 |
| 2026-05-23 12:00 |
20:24:55.99 |
-79:16:43.7 |
HIP 100913 |
10.13 |
| 2026-05-24 00:00 |
20:24:41.76 |
-79:18:03.6 |
HIP 100913 |
9.81 |
| 2026-05-24 12:00 |
20:24:27.18 |
-79:19:23.1 |
HIP 100913 |
9.72 |
| 2026-05-25 00:00 |
20:24:12.26 |
-79:20:42.2 |
HIP 100913 |
9.88 |
| 2026-05-25 12:00 |
20:23:56.99 |
-79:22:01.0 |
HIP 100913 |
10.26 |
| 2026-05-26 00:00 |
20:23:41.38 |
-79:23:19.4 |
HIP 100913 |
10.85 |
| 2026-05-26 12:00 |
20:23:25.42 |
-79:24:37.5 |
HIP 100913 |
11.61 |
| 2026-05-27 00:00 |
20:23:09.11 |
-79:25:55.2 |
HIP 100416 |
10.68 |
| 2026-05-27 12:00 |
20:22:52.46 |
-79:27:12.5 |
HIP 100416 |
9.21 |
| 2026-05-28 00:00 |
20:22:35.46 |
-79:28:29.3 |
HIP 100416 |
7.74 |
| 2026-05-28 12:00 |
20:22:18.11 |
-79:29:45.8 |
HIP 100416 |
6.30 |
| 2026-05-29 00:00 |
20:22:00.42 |
-79:31:01.9 |
HIP 100416 |
4.89 |
| 2026-05-29 12:00 |
20:21:42.38 |
-79:32:17.5 |
HIP 100416 |
3.57 |
| 2026-05-30 00:00 |
20:21:23.99 |
-79:33:32.7 |
HIP 100416 |
2.47 |
| 2026-05-30 12:00 |
20:21:05.26 |
-79:34:47.4 |
HIP 100416 |
2.02 |
| 2026-05-31 00:00 |
20:20:46.18 |
-79:36:01.7 |
HIP 100416 |
2.58 |
| 2026-05-31 12:00 |
20:20:26.76 |
-79:37:15.5 |
HIP 100416 |
3.72 |
| 2026-06-01 00:00 |
20:20:07.00 |
-79:38:28.9 |
HIP 100416 |
5.06 |
| 2026-06-01 12:00 |
20:19:46.89 |
-79:39:41.8 |
HIP 100416 |
6.49 |
| 2026-06-02 00:00 |
20:19:26.43 |
-79:40:54.1 |
HIP 100416 |
7.95 |