| Parameter |
Value |
| Designation |
P/2020 A4 (PANSTARRS-Lemmon) |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2019-11-22T17:20:48.589440Z |
| Orbit solution date (soln_date, UTC) |
2022-08-07T20:12:03Z |
| Obs used |
106 |
| NEO |
- |
| M1 |
15.600 |
| K1 |
8.750 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2020-01-01T12:06:58.176000Z |
| Discovery magnitude (MPC) |
21.40 w |
| Discovery observatory (MPC) |
F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2020-02-03.0000000 |
| e |
0.65370445 |
| q (au) |
2.842514 |
| a (au) |
8.208347 |
| i (deg) |
24.990302 |
| Ω (om, deg) |
312.429623 |
| ω (w, deg) |
144.883054 |
| M (ma, deg) |
3.029158 |
Magnitude
Scatter + Global Linear
$$
M_a = (17.586 + 3.081\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
17.586 |
| n |
3.081 |
| gf |
1.000 |
| gb |
-0.590 |
| k |
0.800 |
| δ90 |
10.000 |
| 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) |
| 2026-06-01 00:00 |
16:43:34.16 |
-45:52:10.2 |
HIP 81847 |
13.17 |
| 2026-06-01 12:00 |
16:43:21.55 |
-45:51:49.8 |
HIP 81847 |
12.78 |
| 2026-06-02 00:00 |
16:43:08.94 |
-45:51:28.7 |
HIP 81847 |
12.77 |
| 2026-06-02 12:00 |
16:42:56.33 |
-45:51:07.0 |
HIP 81847 |
13.16 |
| 2026-06-03 00:00 |
16:42:43.72 |
-45:50:44.7 |
HIP 81847 |
13.91 |
| 2026-06-03 12:00 |
16:42:31.12 |
-45:50:21.7 |
HIP 81847 |
14.96 |
| 2026-06-04 00:00 |
16:42:18.52 |
-45:49:58.1 |
HIP 81847 |
16.26 |
| 2026-06-04 12:00 |
16:42:05.93 |
-45:49:33.9 |
HIP 81847 |
17.75 |
| 2026-06-05 00:00 |
16:41:53.34 |
-45:49:09.0 |
HIP 81684 |
17.44 |
| 2026-06-05 12:00 |
16:41:40.77 |
-45:48:43.5 |
HIP 81684 |
17.00 |
| 2026-06-06 00:00 |
16:41:28.21 |
-45:48:17.3 |
HIP 81684 |
16.85 |
| 2026-06-06 12:00 |
16:41:15.65 |
-45:47:50.6 |
HIP 81684 |
17.01 |
| 2026-06-07 00:00 |
16:41:03.11 |
-45:47:23.2 |
HIP 81684 |
17.46 |
| 2026-06-07 12:00 |
16:40:50.59 |
-45:46:55.1 |
HIP 81549 |
17.08 |
| 2026-06-08 00:00 |
16:40:38.08 |
-45:46:26.5 |
HIP 81549 |
15.30 |
| 2026-06-08 12:00 |
16:40:25.59 |
-45:45:57.2 |
HIP 81549 |
13.65 |
| 2026-06-09 00:00 |
16:40:13.12 |
-45:45:27.4 |
HIP 81549 |
12.20 |
| 2026-06-09 12:00 |
16:40:00.67 |
-45:44:56.9 |
HIP 81549 |
11.02 |
| 2026-06-10 00:00 |
16:39:48.24 |
-45:44:25.8 |
HIP 81549 |
10.21 |
| 2026-06-10 12:00 |
16:39:35.84 |
-45:43:54.1 |
HIP 81549 |
9.85 |
| 2026-06-11 00:00 |
16:39:23.46 |
-45:43:21.8 |
HIP 81549 |
10.00 |
| 2026-06-11 12:00 |
16:39:11.11 |
-45:42:48.9 |
HIP 81549 |
10.64 |
| 2026-06-12 00:00 |
16:38:58.78 |
-45:42:15.4 |
HIP 81549 |
11.68 |
| 2026-06-12 12:00 |
16:38:46.48 |
-45:41:41.3 |
HIP 81549 |
13.02 |
| 2026-06-13 00:00 |
16:38:34.22 |
-45:41:06.7 |
HIP 81549 |
14.58 |
| 2026-06-13 12:00 |
16:38:21.98 |
-45:40:31.4 |
HIP 81549 |
16.30 |
| 2026-06-14 00:00 |
16:38:09.78 |
-45:39:55.6 |
HIP 81549 |
18.13 |
| 2026-06-14 12:00 |
16:37:57.62 |
-45:39:19.1 |
HIP 81549 |
20.04 |
| 2026-06-15 00:00 |
16:37:45.49 |
-45:38:42.1 |
HIP 81258 |
20.34 |
| 2026-06-15 12:00 |
16:37:33.40 |
-45:38:04.6 |
HIP 81258 |
18.26 |
| 2026-06-16 00:00 |
16:37:21.35 |
-45:37:26.5 |
HIP 81258 |
16.21 |
| 2026-06-16 12:00 |
16:37:09.34 |
-45:36:47.8 |
HIP 81258 |
14.22 |
| 2026-06-17 00:00 |
16:36:57.37 |
-45:36:08.5 |
HIP 81258 |
12.30 |
| 2026-06-17 12:00 |
16:36:45.45 |
-45:35:28.8 |
HIP 81258 |
10.51 |
| 2026-06-18 00:00 |
16:36:33.57 |
-45:34:48.4 |
HIP 81258 |
8.90 |
| 2026-06-18 12:00 |
16:36:21.74 |
-45:34:07.6 |
HIP 81258 |
7.59 |
| 2026-06-19 00:00 |
16:36:09.95 |
-45:33:26.2 |
HIP 81258 |
6.76 |
| 2026-06-19 12:00 |
16:35:58.22 |
-45:32:44.2 |
HIP 81258 |
6.59 |
| 2026-06-20 00:00 |
16:35:46.53 |
-45:32:01.8 |
HIP 81258 |
7.11 |
| 2026-06-20 12:00 |
16:35:34.90 |
-45:31:18.8 |
HIP 81258 |
8.20 |
| 2026-06-21 00:00 |
16:35:23.32 |
-45:30:35.3 |
HIP 81176 |
7.55 |
| 2026-06-21 12:00 |
16:35:11.79 |
-45:29:51.3 |
HIP 81176 |
5.57 |
| 2026-06-22 00:00 |
16:35:00.32 |
-45:29:06.8 |
HIP 81176 |
3.79 |