C/2020 H11 (PANSTARRS-Lemmon)
| 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) |
| 2026-02-03 00:00 |
08:39:22.30 |
+20:58:36.1 |
HIP 42428 |
11.28 |
| 2026-02-03 12:00 |
08:39:09.93 |
+20:59:01.5 |
HIP 42428 |
11.20 |
| 2026-02-04 00:00 |
08:38:57.57 |
+20:59:26.7 |
HIP 42428 |
11.85 |
| 2026-02-04 12:00 |
08:38:45.23 |
+20:59:51.7 |
HIP 42428 |
13.14 |
| 2026-02-05 00:00 |
08:38:32.91 |
+21:00:16.5 |
HIP 42428 |
14.88 |
| 2026-02-05 12:00 |
08:38:20.61 |
+21:00:41.2 |
HIP 42428 |
16.94 |
| 2026-02-06 00:00 |
08:38:08.32 |
+21:01:05.8 |
HIP 42428 |
19.22 |
| 2026-02-06 12:00 |
08:37:56.06 |
+21:01:30.1 |
HIP 42428 |
21.64 |
| 2026-02-07 00:00 |
08:37:43.81 |
+21:01:54.3 |
HIP 42428 |
24.15 |
| 2026-02-07 12:00 |
08:37:31.59 |
+21:02:18.3 |
HIP 42428 |
26.74 |
| 2026-02-08 00:00 |
08:37:19.39 |
+21:02:42.1 |
HIP 42428 |
29.37 |
| 2026-02-08 12:00 |
08:37:07.21 |
+21:03:05.7 |
HIP 42106 |
29.88 |
| 2026-02-09 00:00 |
08:36:55.06 |
+21:03:29.2 |
HIP 42106 |
27.02 |
| 2026-02-09 12:00 |
08:36:42.93 |
+21:03:52.4 |
HIP 42106 |
24.17 |
| 2026-02-10 00:00 |
08:36:30.83 |
+21:04:15.5 |
HIP 42106 |
21.33 |
| 2026-02-10 12:00 |
08:36:18.76 |
+21:04:38.4 |
HIP 42106 |
18.49 |
| 2026-02-11 00:00 |
08:36:06.71 |
+21:05:01.0 |
HIP 42106 |
15.66 |
| 2026-02-11 12:00 |
08:35:54.70 |
+21:05:23.5 |
HIP 42106 |
12.85 |
| 2026-02-12 00:00 |
08:35:42.71 |
+21:05:45.8 |
HIP 42106 |
10.04 |
| 2026-02-12 12:00 |
08:35:30.76 |
+21:06:07.9 |
HIP 42106 |
7.26 |
| 2026-02-13 00:00 |
08:35:18.84 |
+21:06:29.7 |
HIP 42106 |
4.53 |
| 2026-02-13 12:00 |
08:35:06.95 |
+21:06:51.4 |
HIP 42106 |
1.99 |
| 2026-02-14 00:00 |
08:34:55.10 |
+21:07:12.8 |
HIP 42106 |
1.75 |
| 2026-02-14 12:00 |
08:34:43.28 |
+21:07:34.1 |
HIP 42106 |
4.20 |
| 2026-02-15 00:00 |
08:34:31.49 |
+21:07:55.1 |
HIP 42106 |
6.89 |
| 2026-02-15 12:00 |
08:34:19.74 |
+21:08:15.9 |
HIP 42106 |
9.62 |
| 2026-02-16 00:00 |
08:34:08.04 |
+21:08:36.5 |
HIP 42106 |
12.35 |
| 2026-02-16 12:00 |
08:33:56.36 |
+21:08:56.9 |
HIP 42106 |
15.09 |
| 2026-02-17 00:00 |
08:33:44.73 |
+21:09:17.0 |
HIP 42106 |
17.81 |
| 2026-02-17 12:00 |
08:33:33.14 |
+21:09:36.9 |
HIP 42106 |
20.53 |
| 2026-02-18 00:00 |
08:33:21.59 |
+21:09:56.6 |
HIP 42106 |
23.23 |
| 2026-02-18 12:00 |
08:33:10.09 |
+21:10:16.1 |
HIP 42106 |
25.93 |
| 2026-02-19 00:00 |
08:32:58.62 |
+21:10:35.3 |
HIP 42106 |
28.62 |
| 2026-02-19 12:00 |
08:32:47.20 |
+21:10:54.3 |
HIP 42106 |
31.30 |
| 2026-02-20 00:00 |
08:32:35.83 |
+21:11:13.0 |
HIP 42106 |
33.97 |
| 2026-02-20 12:00 |
08:32:24.50 |
+21:11:31.6 |
HIP 41710 |
35.24 |
| 2026-02-21 00:00 |
08:32:13.21 |
+21:11:49.9 |
HIP 41710 |
33.29 |
| 2026-02-21 12:00 |
08:32:01.98 |
+21:12:07.9 |
HIP 41710 |
31.46 |
| 2026-02-22 00:00 |
08:31:50.79 |
+21:12:25.7 |
HIP 41710 |
29.75 |
| 2026-02-22 12:00 |
08:31:39.65 |
+21:12:43.2 |
HIP 41710 |
28.18 |
| 2026-02-23 00:00 |
08:31:28.56 |
+21:13:00.6 |
HIP 41710 |
26.78 |
| 2026-02-23 12:00 |
08:31:17.52 |
+21:13:17.6 |
HIP 41710 |
25.58 |
| 2026-02-24 00:00 |
08:31:06.53 |
+21:13:34.4 |
HIP 41710 |
24.59 |