| 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) |
| 2026-05-12 00:00 |
16:51:41.79 |
-45:56:47.2 |
HIP 82550 |
10.38 |
| 2026-05-12 12:00 |
16:51:30.37 |
-45:56:53.1 |
HIP 82550 |
11.83 |
| 2026-05-13 00:00 |
16:51:18.90 |
-45:56:58.3 |
HIP 82550 |
13.42 |
| 2026-05-13 12:00 |
16:51:07.37 |
-45:57:02.9 |
HIP 82550 |
15.13 |
| 2026-05-14 00:00 |
16:50:55.79 |
-45:57:06.9 |
HIP 82550 |
16.91 |
| 2026-05-14 12:00 |
16:50:44.15 |
-45:57:10.2 |
HIP 82550 |
18.76 |
| 2026-05-15 00:00 |
16:50:32.46 |
-45:57:12.8 |
HIP 82550 |
20.65 |
| 2026-05-15 12:00 |
16:50:20.72 |
-45:57:14.8 |
HIP 82550 |
22.57 |
| 2026-05-16 00:00 |
16:50:08.93 |
-45:57:16.1 |
HIP 82238 |
21.46 |
| 2026-05-16 12:00 |
16:49:57.08 |
-45:57:16.8 |
HIP 82238 |
19.40 |
| 2026-05-17 00:00 |
16:49:45.20 |
-45:57:16.8 |
HIP 82238 |
17.33 |
| 2026-05-17 12:00 |
16:49:33.27 |
-45:57:16.2 |
HIP 82238 |
15.26 |
| 2026-05-18 00:00 |
16:49:21.29 |
-45:57:14.9 |
HIP 82238 |
13.18 |
| 2026-05-18 12:00 |
16:49:09.27 |
-45:57:12.9 |
HIP 82238 |
11.09 |
| 2026-05-19 00:00 |
16:48:57.21 |
-45:57:10.3 |
HIP 82238 |
8.99 |
| 2026-05-19 12:00 |
16:48:45.11 |
-45:57:07.1 |
HIP 82238 |
6.89 |
| 2026-05-20 00:00 |
16:48:32.97 |
-45:57:03.1 |
HIP 82238 |
4.78 |
| 2026-05-20 12:00 |
16:48:20.80 |
-45:56:58.5 |
HIP 82238 |
2.67 |
| 2026-05-21 00:00 |
16:48:08.59 |
-45:56:53.3 |
HIP 82238 |
0.57 |
| 2026-05-21 12:00 |
16:47:56.35 |
-45:56:47.3 |
HIP 82238 |
1.60 |
| 2026-05-22 00:00 |
16:47:44.08 |
-45:56:40.7 |
HIP 82238 |
3.73 |
| 2026-05-22 12:00 |
16:47:31.77 |
-45:56:33.5 |
HIP 82238 |
5.87 |
| 2026-05-23 00:00 |
16:47:19.44 |
-45:56:25.6 |
HIP 82148 |
5.16 |
| 2026-05-23 12:00 |
16:47:07.08 |
-45:56:17.0 |
HIP 82148 |
3.59 |
| 2026-05-24 00:00 |
16:46:54.70 |
-45:56:07.7 |
HIP 82148 |
2.90 |
| 2026-05-24 12:00 |
16:46:42.29 |
-45:55:57.8 |
HIP 82148 |
3.64 |
| 2026-05-25 00:00 |
16:46:29.85 |
-45:55:47.3 |
HIP 82148 |
5.23 |
| 2026-05-25 12:00 |
16:46:17.40 |
-45:55:36.0 |
HIP 82148 |
7.14 |
| 2026-05-26 00:00 |
16:46:04.92 |
-45:55:24.1 |
HIP 82148 |
9.17 |
| 2026-05-26 12:00 |
16:45:52.43 |
-45:55:11.6 |
HIP 82148 |
11.25 |
| 2026-05-27 00:00 |
16:45:39.92 |
-45:54:58.4 |
HIP 82148 |
13.37 |
| 2026-05-27 12:00 |
16:45:27.39 |
-45:54:44.5 |
HIP 81987 |
13.17 |
| 2026-05-28 00:00 |
16:45:14.85 |
-45:54:30.0 |
HIP 81987 |
12.71 |
| 2026-05-28 12:00 |
16:45:02.29 |
-45:54:14.8 |
HIP 81987 |
12.63 |
| 2026-05-29 00:00 |
16:44:49.73 |
-45:53:58.9 |
HIP 81987 |
12.95 |
| 2026-05-29 12:00 |
16:44:37.15 |
-45:53:42.4 |
HIP 81987 |
13.62 |
| 2026-05-30 00:00 |
16:44:24.56 |
-45:53:25.3 |
HIP 81987 |
14.61 |
| 2026-05-30 12:00 |
16:44:11.97 |
-45:53:07.5 |
HIP 81987 |
15.86 |
| 2026-05-31 00:00 |
16:43:59.37 |
-45:52:49.0 |
HIP 81847 |
14.97 |
| 2026-05-31 12:00 |
16:43:46.77 |
-45:52:29.9 |
HIP 81847 |
13.92 |
| 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 |