| 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) |
| 2026-07-29 00:00 |
16:24:34.28 |
-44:17:55.5 |
HIP 80443 |
8.40 |
| 2026-07-29 12:00 |
16:24:29.56 |
-44:16:50.6 |
HIP 80443 |
9.68 |
| 2026-07-30 00:00 |
16:24:24.95 |
-44:15:45.7 |
HIP 80443 |
10.97 |
| 2026-07-30 12:00 |
16:24:20.45 |
-44:14:40.8 |
HIP 80443 |
12.25 |
| 2026-07-31 00:00 |
16:24:16.07 |
-44:13:35.8 |
HIP 80443 |
13.54 |
| 2026-07-31 12:00 |
16:24:11.80 |
-44:12:30.9 |
HIP 80443 |
14.82 |
| 2026-08-01 00:00 |
16:24:07.65 |
-44:11:25.9 |
HIP 80443 |
16.09 |
| 2026-08-01 12:00 |
16:24:03.60 |
-44:10:20.9 |
HIP 80443 |
17.35 |
| 2026-08-02 00:00 |
16:23:59.67 |
-44:09:16.0 |
HIP 80443 |
18.60 |
| 2026-08-02 12:00 |
16:23:55.86 |
-44:08:11.0 |
HIP 80443 |
19.85 |
| 2026-08-03 00:00 |
16:23:52.15 |
-44:07:06.1 |
HIP 80212 |
19.40 |
| 2026-08-03 12:00 |
16:23:48.57 |
-44:06:01.2 |
HIP 80212 |
18.22 |
| 2026-08-04 00:00 |
16:23:45.09 |
-44:04:56.3 |
HIP 80212 |
17.07 |
| 2026-08-04 12:00 |
16:23:41.74 |
-44:03:51.5 |
HIP 80212 |
15.95 |
| 2026-08-05 00:00 |
16:23:38.49 |
-44:02:46.7 |
HIP 80212 |
14.86 |
| 2026-08-05 12:00 |
16:23:35.36 |
-44:01:41.9 |
HIP 80212 |
13.82 |
| 2026-08-06 00:00 |
16:23:32.35 |
-44:00:37.2 |
HIP 80212 |
12.82 |
| 2026-08-06 12:00 |
16:23:29.45 |
-43:59:32.5 |
HIP 80212 |
11.89 |
| 2026-08-07 00:00 |
16:23:26.67 |
-43:58:27.9 |
HIP 80212 |
11.02 |
| 2026-08-07 12:00 |
16:23:24.00 |
-43:57:23.4 |
HIP 80212 |
10.24 |
| 2026-08-08 00:00 |
16:23:21.45 |
-43:56:19.0 |
HIP 80212 |
9.56 |
| 2026-08-08 12:00 |
16:23:19.02 |
-43:55:14.6 |
HIP 80212 |
9.01 |
| 2026-08-09 00:00 |
16:23:16.70 |
-43:54:10.3 |
HIP 80212 |
8.60 |
| 2026-08-09 12:00 |
16:23:14.49 |
-43:53:06.1 |
HIP 80212 |
8.34 |
| 2026-08-10 00:00 |
16:23:12.41 |
-43:52:01.9 |
HIP 80212 |
8.26 |
| 2026-08-10 12:00 |
16:23:10.44 |
-43:50:57.9 |
HIP 80212 |
8.35 |
| 2026-08-11 00:00 |
16:23:08.59 |
-43:49:54.0 |
HIP 80212 |
8.60 |
| 2026-08-11 12:00 |
16:23:06.85 |
-43:48:50.2 |
HIP 80212 |
9.00 |
| 2026-08-12 00:00 |
16:23:05.23 |
-43:47:46.5 |
HIP 80212 |
9.53 |
| 2026-08-12 12:00 |
16:23:03.73 |
-43:46:42.9 |
HIP 80212 |
10.16 |
| 2026-08-13 00:00 |
16:23:02.34 |
-43:45:39.5 |
HIP 80212 |
10.87 |
| 2026-08-13 12:00 |
16:23:01.08 |
-43:44:36.2 |
HIP 80212 |
11.65 |
| 2026-08-14 00:00 |
16:22:59.93 |
-43:43:33.0 |
HIP 80212 |
12.48 |
| 2026-08-14 12:00 |
16:22:58.89 |
-43:42:30.0 |
HIP 80212 |
13.35 |
| 2026-08-15 00:00 |
16:22:57.97 |
-43:41:27.1 |
HIP 80212 |
14.26 |
| 2026-08-15 12:00 |
16:22:57.17 |
-43:40:24.3 |
HIP 80212 |
15.19 |
| 2026-08-16 00:00 |
16:22:56.49 |
-43:39:21.7 |
HIP 80212 |
16.14 |
| 2026-08-16 12:00 |
16:22:55.92 |
-43:38:19.3 |
HIP 80381 |
16.59 |
| 2026-08-17 00:00 |
16:22:55.47 |
-43:37:17.0 |
HIP 80381 |
16.78 |
| 2026-08-17 12:00 |
16:22:55.14 |
-43:36:14.9 |
HIP 80381 |
17.00 |
| 2026-08-18 00:00 |
16:22:54.92 |
-43:35:13.0 |
HIP 80381 |
17.26 |
| 2026-08-18 12:00 |
16:22:54.82 |
-43:34:11.3 |
HIP 80381 |
17.56 |
| 2026-08-19 00:00 |
16:22:54.83 |
-43:33:09.7 |
HIP 80381 |
17.89 |