| Parameter |
Value |
| Designation |
C/2020 X4 (Leonard) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2020-11-14T11:24:14.964480Z |
| Orbit solution date (soln_date, UTC) |
2021-09-20T00:12:50Z |
| Obs used |
113 |
| NEO |
- |
| M1 |
7.200 |
| K1 |
13.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2020-12-14T02:02:54.758400Z |
| Discovery magnitude (MPC) |
20.00 G |
| Discovery observatory (MPC) |
G96 · University of Arizona Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-02-28.0000000 |
| e |
0.87940102 |
| q (au) |
5.205810 |
| a (au) |
43.166284 |
| i (deg) |
80.491366 |
| Ω (om, deg) |
161.905337 |
| ω (w, deg) |
139.911326 |
| M (ma, deg) |
0.366726 |
Magnitude
Scatter + Global Linear
$$
M_a = (4.783 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
4.783 |
| n |
6.000 |
| gf |
0.999 |
| gb |
-0.500 |
| k |
1.000 |
| 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) |
| 2026-06-01 00:00 |
03:05:52.69 |
-51:57:21.2 |
HIP 14251 |
25.98 |
| 2026-06-01 12:00 |
03:06:08.40 |
-51:58:05.6 |
HIP 14251 |
27.35 |
| 2026-06-02 00:00 |
03:06:24.07 |
-51:58:50.9 |
HIP 14251 |
28.85 |
| 2026-06-02 12:00 |
03:06:39.71 |
-51:59:37.0 |
HIP 14251 |
30.48 |
| 2026-06-03 00:00 |
03:06:55.32 |
-52:00:24.0 |
HIP 14251 |
32.21 |
| 2026-06-03 12:00 |
03:07:10.89 |
-52:01:11.8 |
HIP 14625 |
32.93 |
| 2026-06-04 00:00 |
03:07:26.44 |
-52:02:00.6 |
HIP 14625 |
31.13 |
| 2026-06-04 12:00 |
03:07:41.94 |
-52:02:50.1 |
HIP 14625 |
29.43 |
| 2026-06-05 00:00 |
03:07:57.42 |
-52:03:40.6 |
HIP 14625 |
27.83 |
| 2026-06-05 12:00 |
03:08:12.85 |
-52:04:31.9 |
HIP 14625 |
26.37 |
| 2026-06-06 00:00 |
03:08:28.26 |
-52:05:24.1 |
HIP 14625 |
25.05 |
| 2026-06-06 12:00 |
03:08:43.62 |
-52:06:17.1 |
HIP 14625 |
23.92 |
| 2026-06-07 00:00 |
03:08:58.95 |
-52:07:11.0 |
HIP 14625 |
22.99 |
| 2026-06-07 12:00 |
03:09:14.24 |
-52:08:05.7 |
HIP 14625 |
22.29 |
| 2026-06-08 00:00 |
03:09:29.49 |
-52:09:01.3 |
HIP 14625 |
21.85 |
| 2026-06-08 12:00 |
03:09:44.70 |
-52:09:57.8 |
HIP 14625 |
21.67 |
| 2026-06-09 00:00 |
03:09:59.87 |
-52:10:55.1 |
HIP 14625 |
21.76 |
| 2026-06-09 12:00 |
03:10:15.01 |
-52:11:53.2 |
HIP 14625 |
22.12 |
| 2026-06-10 00:00 |
03:10:30.10 |
-52:12:52.2 |
HIP 14885 |
21.53 |
| 2026-06-10 12:00 |
03:10:45.15 |
-52:13:52.1 |
HIP 14885 |
20.78 |
| 2026-06-11 00:00 |
03:11:00.15 |
-52:14:52.8 |
HIP 14885 |
20.33 |
| 2026-06-11 12:00 |
03:11:15.12 |
-52:15:54.3 |
HIP 14885 |
20.21 |
| 2026-06-12 00:00 |
03:11:30.04 |
-52:16:56.7 |
HIP 14885 |
20.41 |
| 2026-06-12 12:00 |
03:11:44.91 |
-52:18:00.0 |
HIP 14885 |
20.93 |
| 2026-06-13 00:00 |
03:11:59.75 |
-52:19:04.0 |
HIP 14885 |
21.75 |
| 2026-06-13 12:00 |
03:12:14.53 |
-52:20:08.9 |
HIP 14885 |
22.82 |
| 2026-06-14 00:00 |
03:12:29.27 |
-52:21:14.7 |
HIP 15034 |
21.86 |
| 2026-06-14 12:00 |
03:12:43.96 |
-52:22:21.2 |
HIP 15034 |
19.82 |
| 2026-06-15 00:00 |
03:12:58.60 |
-52:23:28.7 |
HIP 15034 |
17.88 |
| 2026-06-15 12:00 |
03:13:13.20 |
-52:24:36.9 |
HIP 15034 |
16.09 |
| 2026-06-16 00:00 |
03:13:27.74 |
-52:25:46.0 |
HIP 15034 |
14.49 |
| 2026-06-16 12:00 |
03:13:42.24 |
-52:26:55.8 |
HIP 15034 |
13.16 |
| 2026-06-17 00:00 |
03:13:56.68 |
-52:28:06.5 |
HIP 15034 |
12.19 |
| 2026-06-17 12:00 |
03:14:11.08 |
-52:29:18.0 |
HIP 15034 |
11.66 |
| 2026-06-18 00:00 |
03:14:25.42 |
-52:30:30.4 |
HIP 15034 |
11.63 |
| 2026-06-18 12:00 |
03:14:39.71 |
-52:31:43.5 |
HIP 15034 |
12.11 |
| 2026-06-19 00:00 |
03:14:53.94 |
-52:32:57.4 |
HIP 15034 |
13.04 |
| 2026-06-19 12:00 |
03:15:08.12 |
-52:34:12.2 |
HIP 15034 |
14.33 |
| 2026-06-20 00:00 |
03:15:22.25 |
-52:35:27.7 |
HIP 15034 |
15.89 |
| 2026-06-20 12:00 |
03:15:36.32 |
-52:36:44.0 |
HIP 15034 |
17.66 |
| 2026-06-21 00:00 |
03:15:50.34 |
-52:38:01.1 |
HIP 15255 |
19.56 |
| 2026-06-21 12:00 |
03:16:04.29 |
-52:39:19.0 |
HIP 15255 |
17.53 |
| 2026-06-22 00:00 |
03:16:18.20 |
-52:40:37.7 |
HIP 15255 |
15.63 |