| Parameter |
Value |
| Designation |
C/2020 H11 (PANSTARRS-Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2020-09-15T11:27:22.633920Z |
| Orbit solution date (soln_date, UTC) |
2023-04-28T15:42:08Z |
| Obs used |
53 |
| NEO |
- |
| M1 |
7.400 |
| K1 |
11.500 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2020-04-21T13:41:56.256000Z |
| Discovery magnitude (MPC) |
22.10 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2020-03-26.0000000 |
| e |
0.99927122 |
| q (au) |
7.631184 |
| a (au) |
10471.148612 |
| i (deg) |
151.414831 |
| Ω (om, deg) |
303.005797 |
| ω (w, deg) |
91.488781 |
| M (ma, deg) |
359.999840 |
Magnitude
Scatter + Global Linear
$$
M_a = (9.273 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
9.273 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.857 |
| k |
0.800 |
| δ90 |
9.778 |
| 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) |
| 2026-05-12 00:00 |
08:17:12.40 |
+21:05:29.7 |
HIP 40544 |
10.46 |
| 2026-05-12 12:00 |
08:17:12.90 |
+21:05:08.8 |
HIP 40650 |
10.73 |
| 2026-05-13 00:00 |
08:17:13.46 |
+21:04:47.7 |
HIP 40650 |
10.80 |
| 2026-05-13 12:00 |
08:17:14.08 |
+21:04:26.4 |
HIP 40650 |
10.88 |
| 2026-05-14 00:00 |
08:17:14.78 |
+21:04:04.9 |
HIP 40650 |
10.96 |
| 2026-05-14 12:00 |
08:17:15.54 |
+21:03:43.3 |
HIP 40650 |
11.04 |
| 2026-05-15 00:00 |
08:17:16.36 |
+21:03:21.5 |
HIP 40650 |
11.12 |
| 2026-05-15 12:00 |
08:17:17.26 |
+21:02:59.5 |
HIP 40650 |
11.22 |
| 2026-05-16 00:00 |
08:17:18.21 |
+21:02:37.3 |
HIP 40650 |
11.31 |
| 2026-05-16 12:00 |
08:17:19.23 |
+21:02:15.0 |
HIP 40650 |
11.42 |
| 2026-05-17 00:00 |
08:17:20.32 |
+21:01:52.4 |
HIP 40650 |
11.53 |
| 2026-05-17 12:00 |
08:17:21.47 |
+21:01:29.7 |
HIP 40650 |
11.65 |
| 2026-05-18 00:00 |
08:17:22.68 |
+21:01:06.9 |
HIP 40650 |
11.79 |
| 2026-05-18 12:00 |
08:17:23.96 |
+21:00:43.9 |
HIP 40650 |
11.93 |
| 2026-05-19 00:00 |
08:17:25.30 |
+21:00:20.7 |
HIP 40650 |
12.09 |
| 2026-05-19 12:00 |
08:17:26.70 |
+20:59:57.3 |
HIP 40650 |
12.26 |
| 2026-05-20 00:00 |
08:17:28.16 |
+20:59:33.8 |
HIP 40650 |
12.45 |
| 2026-05-20 12:00 |
08:17:29.68 |
+20:59:10.1 |
HIP 40650 |
12.65 |
| 2026-05-21 00:00 |
08:17:31.27 |
+20:58:46.2 |
HIP 40650 |
12.86 |
| 2026-05-21 12:00 |
08:17:32.91 |
+20:58:22.2 |
HIP 40650 |
13.10 |
| 2026-05-22 00:00 |
08:17:34.62 |
+20:57:58.0 |
HIP 40650 |
13.35 |
| 2026-05-22 12:00 |
08:17:36.38 |
+20:57:33.7 |
HIP 40650 |
13.61 |
| 2026-05-23 00:00 |
08:17:38.21 |
+20:57:09.2 |
HIP 40650 |
13.90 |
| 2026-05-23 12:00 |
08:17:40.09 |
+20:56:44.6 |
HIP 40650 |
14.20 |
| 2026-05-24 00:00 |
08:17:42.03 |
+20:56:19.8 |
HIP 40650 |
14.53 |
| 2026-05-24 12:00 |
08:17:44.03 |
+20:55:54.8 |
HIP 40650 |
14.87 |
| 2026-05-25 00:00 |
08:17:46.08 |
+20:55:29.7 |
HIP 40650 |
15.23 |
| 2026-05-25 12:00 |
08:17:48.19 |
+20:55:04.5 |
HIP 40650 |
15.61 |
| 2026-05-26 00:00 |
08:17:50.36 |
+20:54:39.1 |
HIP 40650 |
16.01 |
| 2026-05-26 12:00 |
08:17:52.58 |
+20:54:13.6 |
HIP 40650 |
16.43 |
| 2026-05-27 00:00 |
08:17:54.86 |
+20:53:47.9 |
HIP 40650 |
16.87 |
| 2026-05-27 12:00 |
08:17:57.20 |
+20:53:22.0 |
HIP 40650 |
17.33 |
| 2026-05-28 00:00 |
08:17:59.59 |
+20:52:56.0 |
HIP 40650 |
17.80 |
| 2026-05-28 12:00 |
08:18:02.03 |
+20:52:29.9 |
HIP 40650 |
18.30 |
| 2026-05-29 00:00 |
08:18:04.53 |
+20:52:03.7 |
HIP 40650 |
18.81 |
| 2026-05-29 12:00 |
08:18:07.07 |
+20:51:37.3 |
HIP 40650 |
19.34 |
| 2026-05-30 00:00 |
08:18:09.68 |
+20:51:10.7 |
HIP 40650 |
19.89 |
| 2026-05-30 12:00 |
08:18:12.33 |
+20:50:44.0 |
HIP 40650 |
20.46 |
| 2026-05-31 00:00 |
08:18:15.04 |
+20:50:17.2 |
HIP 40650 |
21.05 |
| 2026-05-31 12:00 |
08:18:17.80 |
+20:49:50.2 |
HIP 40807 |
20.73 |
| 2026-06-01 00:00 |
08:18:20.61 |
+20:49:23.2 |
HIP 40807 |
20.22 |
| 2026-06-01 12:00 |
08:18:23.47 |
+20:48:55.9 |
HIP 40807 |
19.72 |
| 2026-06-02 00:00 |
08:18:26.38 |
+20:48:28.6 |
HIP 40807 |
19.22 |