| Parameter |
Value |
| Designation |
C/2020 H7 (Lemmon) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2020-06-03T12:09:27.060480Z |
| Orbit solution date (soln_date, UTC) |
2021-04-15T23:34:06Z |
| Obs used |
174 |
| NEO |
- |
| M1 |
11.200 |
| K1 |
10.000 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2020-04-29T10:09:34.848000Z |
| Discovery magnitude (MPC) |
20.60 G |
| Discovery observatory (MPC) |
G96 · Mt. Lemmon Survey |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2020-05-21.0000000 |
| e |
0.99942724 |
| q (au) |
4.420107 |
| a (au) |
7717.249417 |
| i (deg) |
135.922901 |
| Ω (om, deg) |
323.529129 |
| ω (w, deg) |
82.769160 |
| M (ma, deg) |
359.999980 |
Magnitude
Scatter + Global Linear
$$
M_a = (11.094 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.094 |
| n |
6.000 |
| gf |
0.867 |
| gb |
-0.784 |
| k |
0.800 |
| δ90 |
9.781 |
| 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) |
| 2026-03-26 00:00 |
08:28:48.30 |
+06:29:59.2 |
HIP 41550 |
13.80 |
| 2026-03-26 12:00 |
08:28:42.92 |
+06:30:25.2 |
HIP 41550 |
12.81 |
| 2026-03-27 00:00 |
08:28:37.61 |
+06:30:51.2 |
HIP 41550 |
11.90 |
| 2026-03-27 12:00 |
08:28:32.37 |
+06:31:16.9 |
HIP 41550 |
11.11 |
| 2026-03-28 00:00 |
08:28:27.20 |
+06:31:42.6 |
HIP 41550 |
10.44 |
| 2026-03-28 12:00 |
08:28:22.10 |
+06:32:08.0 |
HIP 41550 |
9.91 |
| 2026-03-29 00:00 |
08:28:17.06 |
+06:32:33.4 |
HIP 41550 |
9.54 |
| 2026-03-29 12:00 |
08:28:12.09 |
+06:32:58.5 |
HIP 41550 |
9.35 |
| 2026-03-30 00:00 |
08:28:07.19 |
+06:33:23.5 |
HIP 41550 |
9.33 |
| 2026-03-30 12:00 |
08:28:02.36 |
+06:33:48.4 |
HIP 41550 |
9.48 |
| 2026-03-31 00:00 |
08:27:57.60 |
+06:34:13.0 |
HIP 41550 |
9.78 |
| 2026-03-31 12:00 |
08:27:52.91 |
+06:34:37.6 |
HIP 41550 |
10.23 |
| 2026-04-01 00:00 |
08:27:48.28 |
+06:35:01.9 |
HIP 41550 |
10.78 |
| 2026-04-01 12:00 |
08:27:43.72 |
+06:35:26.1 |
HIP 41550 |
11.42 |
| 2026-04-02 00:00 |
08:27:39.23 |
+06:35:50.1 |
HIP 41550 |
12.14 |
| 2026-04-02 12:00 |
08:27:34.81 |
+06:36:13.9 |
HIP 41550 |
12.91 |
| 2026-04-03 00:00 |
08:27:30.46 |
+06:36:37.6 |
HIP 41550 |
13.73 |
| 2026-04-03 12:00 |
08:27:26.18 |
+06:37:01.1 |
HIP 41550 |
14.57 |
| 2026-04-04 00:00 |
08:27:21.97 |
+06:37:24.4 |
HIP 41550 |
15.43 |
| 2026-04-04 12:00 |
08:27:17.82 |
+06:37:47.5 |
HIP 41550 |
16.31 |
| 2026-04-05 00:00 |
08:27:13.75 |
+06:38:10.5 |
HIP 41550 |
17.20 |
| 2026-04-05 12:00 |
08:27:09.74 |
+06:38:33.2 |
HIP 41550 |
18.10 |
| 2026-04-06 00:00 |
08:27:05.81 |
+06:38:55.8 |
HIP 41550 |
18.99 |
| 2026-04-06 12:00 |
08:27:01.94 |
+06:39:18.2 |
HIP 41550 |
19.88 |
| 2026-04-07 00:00 |
08:26:58.14 |
+06:39:40.3 |
HIP 41550 |
20.77 |
| 2026-04-07 12:00 |
08:26:54.42 |
+06:40:02.3 |
HIP 41550 |
21.65 |
| 2026-04-08 00:00 |
08:26:50.76 |
+06:40:24.1 |
HIP 41550 |
22.53 |
| 2026-04-08 12:00 |
08:26:47.17 |
+06:40:45.7 |
HIP 41550 |
23.40 |
| 2026-04-09 00:00 |
08:26:43.65 |
+06:41:07.1 |
HIP 41550 |
24.25 |
| 2026-04-09 12:00 |
08:26:40.20 |
+06:41:28.3 |
HIP 41550 |
25.10 |
| 2026-04-10 00:00 |
08:26:36.82 |
+06:41:49.3 |
HIP 41550 |
25.93 |
| 2026-04-10 12:00 |
08:26:33.52 |
+06:42:10.1 |
HIP 41550 |
26.75 |
| 2026-04-11 00:00 |
08:26:30.28 |
+06:42:30.7 |
HIP 41550 |
27.56 |
| 2026-04-11 12:00 |
08:26:27.11 |
+06:42:51.1 |
HIP 41550 |
28.35 |
| 2026-04-12 00:00 |
08:26:24.01 |
+06:43:11.3 |
HIP 41550 |
29.13 |
| 2026-04-12 12:00 |
08:26:20.98 |
+06:43:31.2 |
HIP 41550 |
29.90 |
| 2026-04-13 00:00 |
08:26:18.02 |
+06:43:50.9 |
HIP 41550 |
30.65 |
| 2026-04-13 12:00 |
08:26:15.13 |
+06:44:10.5 |
HIP 41430 |
31.16 |
| 2026-04-14 00:00 |
08:26:12.30 |
+06:44:29.8 |
HIP 41430 |
31.12 |
| 2026-04-14 12:00 |
08:26:09.55 |
+06:44:48.8 |
HIP 41430 |
31.09 |
| 2026-04-15 00:00 |
08:26:06.87 |
+06:45:07.7 |
HIP 41430 |
31.08 |
| 2026-04-15 12:00 |
08:26:04.26 |
+06:45:26.3 |
HIP 41430 |
31.08 |
| 2026-04-16 00:00 |
08:26:01.72 |
+06:45:44.7 |
HIP 41430 |
31.10 |