| 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) |
| 2026-09-20 00:00 |
14:36:04.69 |
+03:33:13.9 |
HIP 71360 |
8.82 |
| 2026-09-20 12:00 |
14:36:06.58 |
+03:30:26.5 |
HIP 71360 |
7.98 |
| 2026-09-21 00:00 |
14:36:08.59 |
+03:27:39.7 |
HIP 71360 |
8.13 |
| 2026-09-21 12:00 |
14:36:10.71 |
+03:24:53.4 |
HIP 71360 |
9.21 |
| 2026-09-22 00:00 |
14:36:12.94 |
+03:22:07.6 |
HIP 71360 |
10.95 |
| 2026-09-22 12:00 |
14:36:15.28 |
+03:19:22.3 |
HIP 71360 |
13.09 |
| 2026-09-23 00:00 |
14:36:17.74 |
+03:16:37.6 |
HIP 71360 |
15.46 |
| 2026-09-23 12:00 |
14:36:20.30 |
+03:13:53.3 |
HIP 71360 |
17.96 |
| 2026-09-24 00:00 |
14:36:22.96 |
+03:11:09.5 |
HIP 71360 |
20.56 |
| 2026-09-24 12:00 |
14:36:25.73 |
+03:08:26.3 |
HIP 71455 |
18.71 |
| 2026-09-25 00:00 |
14:36:28.61 |
+03:05:43.6 |
HIP 71455 |
15.91 |
| 2026-09-25 12:00 |
14:36:31.59 |
+03:03:01.4 |
HIP 71455 |
13.11 |
| 2026-09-26 00:00 |
14:36:34.67 |
+03:00:19.7 |
HIP 71455 |
10.30 |
| 2026-09-26 12:00 |
14:36:37.85 |
+02:57:38.6 |
HIP 71455 |
7.51 |
| 2026-09-27 00:00 |
14:36:41.13 |
+02:54:58.0 |
HIP 71455 |
4.72 |
| 2026-09-27 12:00 |
14:36:44.50 |
+02:52:17.9 |
HIP 71455 |
1.95 |
| 2026-09-28 00:00 |
14:36:47.97 |
+02:49:38.4 |
HIP 71455 |
1.04 |
| 2026-09-28 12:00 |
14:36:51.54 |
+02:46:59.3 |
HIP 71455 |
3.74 |
| 2026-09-29 00:00 |
14:36:55.20 |
+02:44:20.9 |
HIP 71455 |
6.52 |
| 2026-09-29 12:00 |
14:36:58.95 |
+02:41:42.9 |
HIP 71455 |
9.32 |
| 2026-09-30 00:00 |
14:37:02.80 |
+02:39:05.5 |
HIP 71455 |
12.11 |
| 2026-09-30 12:00 |
14:37:06.73 |
+02:36:28.7 |
HIP 71455 |
14.90 |
| 2026-10-01 00:00 |
14:37:10.75 |
+02:33:52.4 |
HIP 71455 |
17.69 |
| 2026-10-01 12:00 |
14:37:14.86 |
+02:31:16.6 |
HIP 71510 |
15.02 |
| 2026-10-02 00:00 |
14:37:19.06 |
+02:28:41.4 |
HIP 71510 |
12.27 |
| 2026-10-02 12:00 |
14:37:23.34 |
+02:26:06.7 |
HIP 71510 |
9.55 |
| 2026-10-03 00:00 |
14:37:27.71 |
+02:23:32.7 |
HIP 71510 |
6.90 |
| 2026-10-03 12:00 |
14:37:32.16 |
+02:20:59.1 |
HIP 71510 |
4.44 |
| 2026-10-04 00:00 |
14:37:36.69 |
+02:18:26.1 |
HIP 71510 |
2.72 |
| 2026-10-04 12:00 |
14:37:41.30 |
+02:15:53.7 |
HIP 71510 |
3.29 |
| 2026-10-05 00:00 |
14:37:45.99 |
+02:13:21.9 |
HIP 71510 |
5.46 |
| 2026-10-05 12:00 |
14:37:50.75 |
+02:10:50.6 |
HIP 71510 |
8.04 |
| 2026-10-06 00:00 |
14:37:55.60 |
+02:08:19.9 |
HIP 71575 |
8.44 |
| 2026-10-06 12:00 |
14:38:00.52 |
+02:05:49.8 |
HIP 71575 |
5.73 |
| 2026-10-07 00:00 |
14:38:05.51 |
+02:03:20.3 |
HIP 71575 |
3.13 |
| 2026-10-07 12:00 |
14:38:10.58 |
+02:00:51.3 |
HIP 71575 |
1.51 |
| 2026-10-08 00:00 |
14:38:15.72 |
+01:58:23.0 |
HIP 71575 |
3.19 |
| 2026-10-08 12:00 |
14:38:20.92 |
+01:55:55.2 |
HIP 71575 |
5.80 |
| 2026-10-09 00:00 |
14:38:26.20 |
+01:53:28.0 |
HIP 71575 |
8.51 |
| 2026-10-09 12:00 |
14:38:31.54 |
+01:51:01.4 |
HIP 71575 |
11.25 |
| 2026-10-10 00:00 |
14:38:36.95 |
+01:48:35.5 |
HIP 71575 |
14.01 |
| 2026-10-10 12:00 |
14:38:42.43 |
+01:46:10.1 |
HIP 71575 |
16.78 |
| 2026-10-11 00:00 |
14:38:47.97 |
+01:43:45.3 |
HIP 71575 |
19.54 |