| Parameter |
Value |
| Designation |
C/2026 H2 (Leonard) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2026-03-17T07:54:53.320320Z |
| Orbit solution date (soln_date, UTC) |
2026-07-28T14:12:18Z |
| Obs used |
379 |
| NEO |
- |
| M1 |
9.800 |
| K1 |
10.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2026-04-16T10:54:10.396800Z |
| Discovery magnitude (MPC) |
19.65 G |
| Discovery observatory (MPC) |
G96 · University of Arizona Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2026-05-09.0000000 |
| e |
1.00222771 |
| q (au) |
4.546522 |
| a (au) |
-2040.891292 |
| i (deg) |
148.650724 |
| Ω (om, deg) |
5.456073 |
| ω (w, deg) |
111.549054 |
| M (ma, deg) |
0.000563 |
Magnitude
Scatter + Global Linear
$$
M_a = (12.311 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
12.311 |
| n |
2.000 |
| gf |
0.999 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
9.999 |
| 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
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
14:49:04.74 |
+08:59:07.0 |
HIP 72317 |
31.76 |
| 2026-07-29 12:00 |
14:48:45.14 |
+08:55:59.4 |
HIP 72317 |
30.11 |
| 2026-07-30 00:00 |
14:48:25.83 |
+08:52:51.4 |
HIP 72311 |
28.20 |
| 2026-07-30 12:00 |
14:48:06.81 |
+08:49:43.2 |
HIP 72311 |
22.90 |
| 2026-07-31 00:00 |
14:47:48.08 |
+08:46:34.6 |
HIP 72311 |
17.85 |
| 2026-07-31 12:00 |
14:47:29.64 |
+08:43:25.8 |
HIP 72311 |
13.25 |
| 2026-08-01 00:00 |
14:47:11.48 |
+08:40:16.7 |
HIP 72311 |
9.68 |
| 2026-08-01 12:00 |
14:46:53.61 |
+08:37:07.4 |
HIP 72311 |
8.44 |
| 2026-08-02 00:00 |
14:46:36.02 |
+08:33:57.9 |
HIP 72311 |
10.31 |
| 2026-08-02 12:00 |
14:46:18.72 |
+08:30:48.2 |
HIP 72311 |
14.04 |
| 2026-08-03 00:00 |
14:46:01.69 |
+08:27:38.2 |
HIP 72311 |
18.50 |
| 2026-08-03 12:00 |
14:45:44.94 |
+08:24:28.1 |
HIP 72162 |
15.04 |
| 2026-08-04 00:00 |
14:45:28.47 |
+08:21:17.8 |
HIP 72162 |
11.86 |
| 2026-08-04 12:00 |
14:45:12.27 |
+08:18:07.4 |
HIP 72162 |
10.38 |
| 2026-08-05 00:00 |
14:44:56.35 |
+08:14:56.8 |
HIP 72162 |
11.21 |
| 2026-08-05 12:00 |
14:44:40.70 |
+08:11:46.0 |
HIP 72162 |
13.89 |
| 2026-08-06 00:00 |
14:44:25.31 |
+08:08:35.1 |
HIP 72162 |
17.56 |
| 2026-08-06 12:00 |
14:44:10.20 |
+08:05:24.2 |
HIP 71946 |
18.61 |
| 2026-08-07 00:00 |
14:43:55.35 |
+08:02:13.1 |
HIP 71946 |
15.10 |
| 2026-08-07 12:00 |
14:43:40.77 |
+07:59:01.9 |
HIP 71946 |
12.59 |
| 2026-08-08 00:00 |
14:43:26.45 |
+07:55:50.6 |
HIP 71946 |
11.68 |
| 2026-08-08 12:00 |
14:43:12.39 |
+07:52:39.3 |
HIP 71946 |
12.66 |
| 2026-08-09 00:00 |
14:42:58.59 |
+07:49:28.0 |
HIP 71951 |
12.65 |
| 2026-08-09 12:00 |
14:42:45.05 |
+07:46:16.5 |
HIP 71951 |
9.97 |
| 2026-08-10 00:00 |
14:42:31.77 |
+07:43:05.1 |
HIP 71951 |
8.98 |
| 2026-08-10 12:00 |
14:42:18.74 |
+07:39:53.6 |
HIP 71951 |
10.14 |
| 2026-08-11 00:00 |
14:42:05.97 |
+07:36:42.1 |
HIP 71822 |
8.65 |
| 2026-08-11 12:00 |
14:41:53.45 |
+07:33:30.7 |
HIP 71822 |
6.73 |
| 2026-08-12 00:00 |
14:41:41.17 |
+07:30:19.2 |
HIP 71822 |
7.47 |
| 2026-08-12 12:00 |
14:41:29.15 |
+07:27:07.8 |
HIP 71822 |
10.25 |
| 2026-08-13 00:00 |
14:41:17.37 |
+07:23:56.4 |
HIP 71822 |
13.86 |
| 2026-08-13 12:00 |
14:41:05.83 |
+07:20:45.0 |
HIP 71704 |
15.38 |
| 2026-08-14 00:00 |
14:40:54.54 |
+07:17:33.7 |
HIP 71704 |
12.91 |
| 2026-08-14 12:00 |
14:40:43.49 |
+07:14:22.5 |
HIP 71704 |
11.58 |
| 2026-08-15 00:00 |
14:40:32.68 |
+07:11:11.4 |
HIP 71704 |
11.73 |
| 2026-08-15 12:00 |
14:40:22.10 |
+07:08:00.3 |
HIP 71704 |
13.27 |
| 2026-08-16 00:00 |
14:40:11.76 |
+07:04:49.4 |
HIP 71704 |
15.78 |
| 2026-08-16 12:00 |
14:40:01.65 |
+07:01:38.6 |
HIP 71704 |
18.85 |
| 2026-08-17 00:00 |
14:39:51.77 |
+06:58:27.9 |
HIP 71704 |
22.22 |
| 2026-08-17 12:00 |
14:39:42.12 |
+06:55:17.3 |
HIP 71704 |
25.76 |
| 2026-08-18 00:00 |
14:39:32.70 |
+06:52:06.9 |
HIP 71704 |
29.40 |
| 2026-08-18 12:00 |
14:39:23.50 |
+06:48:56.6 |
HIP 71704 |
33.09 |
| 2026-08-19 00:00 |
14:39:14.53 |
+06:45:46.4 |
HIP 71704 |
36.80 |