| Parameter |
Value |
| Designation |
C/2026 H2 (Leonard) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2026-03-17T03:07:21.262080Z |
| Orbit solution date (soln_date, UTC) |
2026-05-28T12:12:20Z |
| Obs used |
301 |
| 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) |
2026-04-29.0000000 |
| e |
1.00135457 |
| q (au) |
4.546083 |
| a (au) |
-3356.118528 |
| i (deg) |
148.650256 |
| Ω (om, deg) |
5.459021 |
| ω (w, deg) |
111.524045 |
| M (ma, deg) |
0.000217 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.637 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.637 |
| n |
6.000 |
| gf |
0.985 |
| gb |
-1.000 |
| k |
1.000 |
| δ90 |
9.934 |
| 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) |
| 2026-06-01 00:00 |
16:02:10.91 |
+12:48:20.7 |
HIP 78444 |
27.65 |
| 2026-06-01 12:00 |
16:01:18.50 |
+12:48:24.6 |
HIP 78444 |
20.87 |
| 2026-06-02 00:00 |
16:00:26.19 |
+12:48:25.7 |
HIP 78444 |
20.78 |
| 2026-06-02 12:00 |
15:59:33.99 |
+12:48:23.9 |
HIP 78223 |
17.04 |
| 2026-06-03 00:00 |
15:58:41.91 |
+12:48:19.3 |
HIP 78223 |
4.62 |
| 2026-06-03 12:00 |
15:57:49.96 |
+12:48:11.8 |
HIP 78223 |
8.62 |
| 2026-06-04 00:00 |
15:56:58.13 |
+12:48:01.4 |
HIP 78097 |
19.59 |
| 2026-06-04 12:00 |
15:56:06.45 |
+12:47:48.2 |
HIP 78097 |
21.37 |
| 2026-06-05 00:00 |
15:55:14.91 |
+12:47:32.2 |
HIP 77830 |
27.26 |
| 2026-06-05 12:00 |
15:54:23.51 |
+12:47:13.3 |
HIP 77830 |
16.51 |
| 2026-06-06 00:00 |
15:53:32.27 |
+12:46:51.6 |
HIP 77830 |
10.81 |
| 2026-06-06 12:00 |
15:52:41.19 |
+12:46:27.2 |
HIP 77830 |
16.54 |
| 2026-06-07 00:00 |
15:51:50.27 |
+12:46:00.0 |
HIP 77830 |
27.19 |
| 2026-06-07 12:00 |
15:50:59.53 |
+12:45:29.9 |
HIP 77616 |
22.52 |
| 2026-06-08 00:00 |
15:50:08.96 |
+12:44:57.1 |
HIP 77506 |
14.27 |
| 2026-06-08 12:00 |
15:49:18.57 |
+12:44:21.6 |
HIP 77455 |
6.91 |
| 2026-06-09 00:00 |
15:48:28.37 |
+12:43:43.3 |
HIP 77455 |
5.40 |
| 2026-06-09 12:00 |
15:47:38.36 |
+12:43:02.3 |
HIP 77455 |
17.59 |
| 2026-06-10 00:00 |
15:46:48.55 |
+12:42:18.6 |
HIP 77214 |
15.82 |
| 2026-06-10 12:00 |
15:45:58.94 |
+12:41:32.3 |
HIP 77214 |
8.11 |
| 2026-06-11 00:00 |
15:45:09.54 |
+12:40:43.2 |
HIP 77214 |
13.18 |
| 2026-06-11 12:00 |
15:44:20.35 |
+12:39:51.5 |
HIP 77041 |
11.14 |
| 2026-06-12 00:00 |
15:43:31.38 |
+12:38:57.2 |
HIP 77041 |
11.65 |
| 2026-06-12 12:00 |
15:42:42.63 |
+12:38:00.2 |
HIP 76866 |
18.61 |
| 2026-06-13 00:00 |
15:41:54.10 |
+12:37:00.7 |
HIP 76866 |
13.94 |
| 2026-06-13 12:00 |
15:41:05.81 |
+12:35:58.6 |
HIP 76866 |
18.00 |
| 2026-06-14 00:00 |
15:40:17.76 |
+12:34:53.9 |
HIP 76707 |
11.78 |
| 2026-06-14 12:00 |
15:39:29.94 |
+12:33:46.7 |
HIP 76707 |
11.07 |
| 2026-06-15 00:00 |
15:38:42.38 |
+12:32:36.9 |
HIP 76612 |
17.43 |
| 2026-06-15 12:00 |
15:37:55.06 |
+12:31:24.7 |
HIP 76492 |
15.37 |
| 2026-06-16 00:00 |
15:37:07.99 |
+12:30:10.1 |
HIP 76492 |
12.66 |
| 2026-06-16 12:00 |
15:36:21.19 |
+12:28:52.9 |
HIP 76492 |
18.68 |
| 2026-06-17 00:00 |
15:35:34.64 |
+12:27:33.4 |
HIP 76368 |
27.71 |
| 2026-06-17 12:00 |
15:34:48.36 |
+12:26:11.5 |
HIP 76368 |
32.60 |
| 2026-06-18 00:00 |
15:34:02.35 |
+12:24:47.2 |
HIP 76257 |
36.51 |
| 2026-06-18 12:00 |
15:33:16.62 |
+12:23:20.6 |
HIP 76169 |
36.93 |
| 2026-06-19 00:00 |
15:32:31.16 |
+12:21:51.7 |
HIP 75910 |
36.31 |
| 2026-06-19 12:00 |
15:31:45.98 |
+12:20:20.5 |
HIP 75910 |
26.09 |
| 2026-06-20 00:00 |
15:31:01.08 |
+12:18:47.0 |
HIP 75910 |
17.07 |
| 2026-06-20 12:00 |
15:30:16.47 |
+12:17:11.3 |
HIP 75910 |
12.12 |
| 2026-06-21 00:00 |
15:29:32.15 |
+12:15:33.5 |
HIP 75910 |
15.58 |
| 2026-06-21 12:00 |
15:28:48.12 |
+12:13:53.4 |
HIP 75910 |
23.97 |
| 2026-06-22 00:00 |
15:28:04.39 |
+12:12:11.2 |
HIP 75714 |
20.49 |