| Parameter |
Value |
| Designation |
P/2021 L2 (Leonard) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2021-07-24T13:05:37.386240Z |
| Orbit solution date (soln_date, UTC) |
2021-11-20T19:13:06Z |
| Obs used |
131 |
| NEO |
- |
| M1 |
16.200 |
| K1 |
11.500 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2021-06-08T09:29:49.689600Z |
| Discovery magnitude (MPC) |
20.31 G |
| Discovery observatory (MPC) |
G96 · University of Arizona Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-07-26.0000000 |
| e |
0.52175163 |
| q (au) |
1.938550 |
| a (au) |
4.053438 |
| i (deg) |
21.068982 |
| Ω (om, deg) |
266.675736 |
| ω (w, deg) |
51.538655 |
| M (ma, deg) |
0.175655 |
Magnitude
Scatter + Global Linear
$$
M_a = (18.492 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
18.492 |
| n |
2.000 |
| gf |
0.800 |
| gb |
-1.000 |
| k |
0.965 |
| δ90 |
1.000 |
| 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 |
10:15:07.85 |
-07:23:50.7 |
HIP 50138 |
16.30 |
| 2026-09-20 12:00 |
10:15:27.37 |
-07:26:23.2 |
HIP 50138 |
21.76 |
| 2026-09-21 00:00 |
10:15:46.86 |
-07:28:56.1 |
HIP 50138 |
27.21 |
| 2026-09-21 12:00 |
10:16:06.31 |
-07:31:29.4 |
HIP 50138 |
32.66 |
| 2026-09-22 00:00 |
10:16:25.72 |
-07:34:03.1 |
HIP 50490 |
32.69 |
| 2026-09-22 12:00 |
10:16:45.09 |
-07:36:37.2 |
HIP 50490 |
28.40 |
| 2026-09-23 00:00 |
10:17:04.42 |
-07:39:11.7 |
HIP 50490 |
24.59 |
| 2026-09-23 12:00 |
10:17:23.71 |
-07:41:46.6 |
HIP 50490 |
21.50 |
| 2026-09-24 00:00 |
10:17:42.96 |
-07:44:21.8 |
HIP 50490 |
19.48 |
| 2026-09-24 12:00 |
10:18:02.17 |
-07:46:57.5 |
HIP 50414 |
18.20 |
| 2026-09-25 00:00 |
10:18:21.34 |
-07:49:33.5 |
HIP 50414 |
18.12 |
| 2026-09-25 12:00 |
10:18:40.47 |
-07:52:09.9 |
HIP 50414 |
19.58 |
| 2026-09-26 00:00 |
10:18:59.55 |
-07:54:46.7 |
HIP 50414 |
22.28 |
| 2026-09-26 12:00 |
10:19:18.59 |
-07:57:23.8 |
HIP 50414 |
25.82 |
| 2026-09-27 00:00 |
10:19:37.59 |
-08:00:01.3 |
HIP 50414 |
29.91 |
| 2026-09-27 12:00 |
10:19:56.54 |
-08:02:39.2 |
HIP 50414 |
34.35 |
| 2026-09-28 00:00 |
10:20:15.45 |
-08:05:17.4 |
HIP 50581 |
36.94 |
| 2026-09-28 12:00 |
10:20:34.31 |
-08:07:56.0 |
HIP 50581 |
35.25 |
| 2026-09-29 00:00 |
10:20:53.13 |
-08:10:34.9 |
HIP 50698 |
32.25 |
| 2026-09-29 12:00 |
10:21:11.89 |
-08:13:14.2 |
HIP 50698 |
29.35 |
| 2026-09-30 00:00 |
10:21:30.61 |
-08:15:53.8 |
HIP 50698 |
27.19 |
| 2026-09-30 12:00 |
10:21:49.29 |
-08:18:33.8 |
HIP 50698 |
25.95 |
| 2026-10-01 00:00 |
10:22:07.91 |
-08:21:14.1 |
HIP 50698 |
25.77 |
| 2026-10-01 12:00 |
10:22:26.49 |
-08:23:54.7 |
HIP 50698 |
26.66 |
| 2026-10-02 00:00 |
10:22:45.01 |
-08:26:35.7 |
HIP 50698 |
28.52 |
| 2026-10-02 12:00 |
10:23:03.48 |
-08:29:17.0 |
HIP 50698 |
31.16 |
| 2026-10-03 00:00 |
10:23:21.90 |
-08:31:58.6 |
HIP 50698 |
34.41 |
| 2026-10-03 12:00 |
10:23:40.27 |
-08:34:40.5 |
HIP 50698 |
38.10 |
| 2026-10-04 00:00 |
10:23:58.59 |
-08:37:22.8 |
HIP 50698 |
42.12 |
| 2026-10-04 12:00 |
10:24:16.85 |
-08:40:05.3 |
HIP 50698 |
46.38 |
| 2026-10-05 00:00 |
10:24:35.06 |
-08:42:48.2 |
HIP 51165 |
47.85 |
| 2026-10-05 12:00 |
10:24:53.21 |
-08:45:31.4 |
HIP 51165 |
42.67 |
| 2026-10-06 00:00 |
10:25:11.31 |
-08:48:14.9 |
HIP 51165 |
37.51 |
| 2026-10-06 12:00 |
10:25:29.35 |
-08:50:58.6 |
HIP 51165 |
32.39 |
| 2026-10-07 00:00 |
10:25:47.33 |
-08:53:42.7 |
HIP 51165 |
27.31 |
| 2026-10-07 12:00 |
10:26:05.25 |
-08:56:27.0 |
HIP 51165 |
22.31 |
| 2026-10-08 00:00 |
10:26:23.11 |
-08:59:11.6 |
HIP 51165 |
17.42 |
| 2026-10-08 12:00 |
10:26:40.92 |
-09:01:56.5 |
HIP 51165 |
12.79 |
| 2026-10-09 00:00 |
10:26:58.66 |
-09:04:41.6 |
HIP 51165 |
8.79 |
| 2026-10-09 12:00 |
10:27:16.34 |
-09:07:27.1 |
HIP 51165 |
6.65 |
| 2026-10-10 00:00 |
10:27:33.96 |
-09:10:12.7 |
HIP 51165 |
8.02 |
| 2026-10-10 12:00 |
10:27:51.51 |
-09:12:58.7 |
HIP 51165 |
11.71 |
| 2026-10-11 00:00 |
10:28:09.00 |
-09:15:44.8 |
HIP 51165 |
16.19 |