| Parameter |
Value |
| Designation |
C/2026 H2 (Leonard) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2026-03-17T20:32:34.313280Z |
| Orbit solution date (soln_date, UTC) |
2026-05-08T13:42:11Z |
| Obs used |
229 |
| 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 · Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2026-04-22.0000000 |
| e |
1.00390925 |
| q (au) |
4.547271 |
| a (au) |
-1163.209293 |
| i (deg) |
148.652838 |
| Ω (om, deg) |
5.446450 |
| ω (w, deg) |
111.614316 |
| M (ma, deg) |
0.000873 |
Magnitude
Scatter + Global Linear
$$
M_a = (5.574 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
5.574 |
| n |
6.000 |
| gf |
0.983 |
| gb |
-0.583 |
| k |
1.000 |
| δ90 |
9.949 |
| 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) |
| 2026-05-12 00:00 |
16:37:21.49 |
+12:06:48.3 |
HIP 81218 |
30.17 |
| 2026-05-12 12:00 |
16:36:30.11 |
+12:08:43.2 |
HIP 81218 |
18.91 |
| 2026-05-13 00:00 |
16:35:38.59 |
+12:10:35.7 |
HIP 81218 |
11.28 |
| 2026-05-13 12:00 |
16:34:46.92 |
+12:12:25.7 |
HIP 81218 |
14.86 |
| 2026-05-14 00:00 |
16:33:55.10 |
+12:14:13.2 |
HIP 81218 |
25.30 |
| 2026-05-14 12:00 |
16:33:03.15 |
+12:15:58.2 |
HIP 81018 |
21.25 |
| 2026-05-15 00:00 |
16:32:11.07 |
+12:17:40.6 |
HIP 80936 |
11.25 |
| 2026-05-15 12:00 |
16:31:18.87 |
+12:19:20.5 |
HIP 80936 |
7.43 |
| 2026-05-16 00:00 |
16:30:26.55 |
+12:20:57.8 |
HIP 80936 |
17.77 |
| 2026-05-16 12:00 |
16:29:34.12 |
+12:22:32.4 |
HIP 80773 |
26.26 |
| 2026-05-17 00:00 |
16:28:41.58 |
+12:24:04.4 |
HIP 80773 |
30.44 |
| 2026-05-17 12:00 |
16:27:48.95 |
+12:25:33.7 |
HIP 80553 |
26.91 |
| 2026-05-18 00:00 |
16:26:56.23 |
+12:27:00.4 |
HIP 80553 |
23.78 |
| 2026-05-18 12:00 |
16:26:03.43 |
+12:28:24.3 |
HIP 80553 |
27.22 |
| 2026-05-19 00:00 |
16:25:10.55 |
+12:29:45.5 |
HIP 80332 |
28.10 |
| 2026-05-19 12:00 |
16:24:17.60 |
+12:31:03.9 |
HIP 80332 |
21.33 |
| 2026-05-20 00:00 |
16:23:24.59 |
+12:32:19.6 |
HIP 80332 |
21.45 |
| 2026-05-20 12:00 |
16:22:31.52 |
+12:33:32.5 |
HIP 80182 |
21.51 |
| 2026-05-21 00:00 |
16:21:38.40 |
+12:34:42.6 |
HIP 80182 |
22.92 |
| 2026-05-21 12:00 |
16:20:45.24 |
+12:35:49.9 |
HIP 79952 |
23.15 |
| 2026-05-22 00:00 |
16:19:52.05 |
+12:36:54.4 |
HIP 79952 |
10.64 |
| 2026-05-22 12:00 |
16:18:58.82 |
+12:37:56.0 |
HIP 79952 |
5.41 |
| 2026-05-23 00:00 |
16:18:05.58 |
+12:38:54.8 |
HIP 79947 |
16.15 |
| 2026-05-23 12:00 |
16:17:12.32 |
+12:39:50.8 |
HIP 79858 |
26.58 |
| 2026-05-24 00:00 |
16:16:19.05 |
+12:40:43.9 |
HIP 79858 |
34.16 |
| 2026-05-24 12:00 |
16:15:25.77 |
+12:41:34.1 |
HIP 79465 |
36.67 |
| 2026-05-25 00:00 |
16:14:32.51 |
+12:42:21.5 |
HIP 79465 |
23.79 |
| 2026-05-25 12:00 |
16:13:39.25 |
+12:43:05.9 |
HIP 79465 |
11.26 |
| 2026-05-26 00:00 |
16:12:46.01 |
+12:43:47.5 |
HIP 79465 |
5.12 |
| 2026-05-26 12:00 |
16:11:52.80 |
+12:44:26.2 |
HIP 79444 |
16.12 |
| 2026-05-27 00:00 |
16:10:59.61 |
+12:45:02.0 |
HIP 79444 |
27.87 |
| 2026-05-27 12:00 |
16:10:06.47 |
+12:45:34.9 |
HIP 79139 |
16.71 |
| 2026-05-28 00:00 |
16:09:13.37 |
+12:46:04.9 |
HIP 79139 |
9.85 |
| 2026-05-28 12:00 |
16:08:20.32 |
+12:46:32.0 |
HIP 79139 |
15.83 |
| 2026-05-29 00:00 |
16:07:27.32 |
+12:46:56.3 |
HIP 79028 |
25.09 |
| 2026-05-29 12:00 |
16:06:34.39 |
+12:47:17.6 |
HIP 79028 |
30.83 |
| 2026-05-30 00:00 |
16:05:41.53 |
+12:47:36.0 |
HIP 78773 |
23.24 |
| 2026-05-30 12:00 |
16:04:48.75 |
+12:47:51.5 |
HIP 78773 |
20.40 |
| 2026-05-31 00:00 |
16:03:56.05 |
+12:48:04.1 |
HIP 78773 |
24.98 |
| 2026-05-31 12:00 |
16:03:03.43 |
+12:48:13.8 |
HIP 78773 |
34.09 |
| 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 |