| 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 · University of Arizona 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
$$
M_a = (11.096 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
11.096 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.784 |
| k |
0.800 |
| δ90 |
9.996 |
| 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) |
| 2026-09-20 00:00 |
08:44:22.77 |
+04:58:45.8 |
HIP 42899 |
18.51 |
| 2026-09-20 12:00 |
08:44:25.98 |
+04:58:00.7 |
HIP 42899 |
19.18 |
| 2026-09-21 00:00 |
08:44:29.15 |
+04:57:15.5 |
HIP 42862 |
19.82 |
| 2026-09-21 12:00 |
08:44:32.28 |
+04:56:30.4 |
HIP 42862 |
19.38 |
| 2026-09-22 00:00 |
08:44:35.36 |
+04:55:45.4 |
HIP 42862 |
18.99 |
| 2026-09-22 12:00 |
08:44:38.40 |
+04:55:00.3 |
HIP 42862 |
18.65 |
| 2026-09-23 00:00 |
08:44:41.39 |
+04:54:15.3 |
HIP 42862 |
18.36 |
| 2026-09-23 12:00 |
08:44:44.34 |
+04:53:30.3 |
HIP 42862 |
18.12 |
| 2026-09-24 00:00 |
08:44:47.24 |
+04:52:45.3 |
HIP 42981 |
17.51 |
| 2026-09-24 12:00 |
08:44:50.10 |
+04:52:00.4 |
HIP 42981 |
16.47 |
| 2026-09-25 00:00 |
08:44:52.92 |
+04:51:15.5 |
HIP 42981 |
15.45 |
| 2026-09-25 12:00 |
08:44:55.69 |
+04:50:30.6 |
HIP 42981 |
14.43 |
| 2026-09-26 00:00 |
08:44:58.41 |
+04:49:45.8 |
HIP 42981 |
13.42 |
| 2026-09-26 12:00 |
08:45:01.08 |
+04:49:01.0 |
HIP 42981 |
12.42 |
| 2026-09-27 00:00 |
08:45:03.71 |
+04:48:16.3 |
HIP 42981 |
11.43 |
| 2026-09-27 12:00 |
08:45:06.30 |
+04:47:31.6 |
HIP 42981 |
10.45 |
| 2026-09-28 00:00 |
08:45:08.83 |
+04:46:47.0 |
HIP 42981 |
9.47 |
| 2026-09-28 12:00 |
08:45:11.32 |
+04:46:02.4 |
HIP 42981 |
8.51 |
| 2026-09-29 00:00 |
08:45:13.76 |
+04:45:17.8 |
HIP 42981 |
7.55 |
| 2026-09-29 12:00 |
08:45:16.15 |
+04:44:33.4 |
HIP 42981 |
6.60 |
| 2026-09-30 00:00 |
08:45:18.49 |
+04:43:48.9 |
HIP 42981 |
5.67 |
| 2026-09-30 12:00 |
08:45:20.79 |
+04:43:04.6 |
HIP 42981 |
4.74 |
| 2026-10-01 00:00 |
08:45:23.04 |
+04:42:20.3 |
HIP 42981 |
3.84 |
| 2026-10-01 12:00 |
08:45:25.23 |
+04:41:36.0 |
HIP 42981 |
2.95 |
| 2026-10-02 00:00 |
08:45:27.38 |
+04:40:51.9 |
HIP 42981 |
2.11 |
| 2026-10-02 12:00 |
08:45:29.48 |
+04:40:07.8 |
HIP 42981 |
1.36 |
| 2026-10-03 00:00 |
08:45:31.52 |
+04:39:23.7 |
HIP 42981 |
0.96 |
| 2026-10-03 12:00 |
08:45:33.52 |
+04:38:39.8 |
HIP 42981 |
1.26 |
| 2026-10-04 00:00 |
08:45:35.46 |
+04:37:55.9 |
HIP 42981 |
1.95 |
| 2026-10-04 12:00 |
08:45:37.36 |
+04:37:12.1 |
HIP 42981 |
2.75 |
| 2026-10-05 00:00 |
08:45:39.20 |
+04:36:28.3 |
HIP 42981 |
3.57 |
| 2026-10-05 12:00 |
08:45:40.99 |
+04:35:44.7 |
HIP 42981 |
4.40 |
| 2026-10-06 00:00 |
08:45:42.73 |
+04:35:01.1 |
HIP 42981 |
5.24 |
| 2026-10-06 12:00 |
08:45:44.41 |
+04:34:17.7 |
HIP 42981 |
6.07 |
| 2026-10-07 00:00 |
08:45:46.05 |
+04:33:34.3 |
HIP 42981 |
6.89 |
| 2026-10-07 12:00 |
08:45:47.63 |
+04:32:51.0 |
HIP 42981 |
7.71 |
| 2026-10-08 00:00 |
08:45:49.15 |
+04:32:07.8 |
HIP 42981 |
8.53 |
| 2026-10-08 12:00 |
08:45:50.63 |
+04:31:24.8 |
HIP 43070 |
8.16 |
| 2026-10-09 00:00 |
08:45:52.04 |
+04:30:41.8 |
HIP 43070 |
7.73 |
| 2026-10-09 12:00 |
08:45:53.41 |
+04:29:58.9 |
HIP 43070 |
7.37 |
| 2026-10-10 00:00 |
08:45:54.72 |
+04:29:16.1 |
HIP 43070 |
7.09 |
| 2026-10-10 12:00 |
08:45:55.97 |
+04:28:33.5 |
HIP 43070 |
6.90 |
| 2026-10-11 00:00 |
08:45:57.17 |
+04:27:50.9 |
HIP 43070 |
6.81 |