| Parameter |
Value |
| Designation |
C/2020 P3 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2021-04-20T20:06:04.121280Z |
| Orbit solution date (soln_date, UTC) |
2024-04-29T13:12:18Z |
| Obs used |
698 |
| NEO |
- |
| M1 |
5.800 |
| K1 |
10.000 |
| PC |
0.030 |
| Discovery observation (MPC, UTC) |
2020-08-09T13:40:41.433600Z |
| Discovery magnitude (MPC) |
19.01 o |
| Discovery observatory (MPC) |
T08 · ATLAS-MLO, Mauna Loa |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-07-14.0000000 |
| e |
0.99914404 |
| q (au) |
6.812376 |
| a (au) |
7958.786111 |
| i (deg) |
61.884995 |
| Ω (om, deg) |
19.484342 |
| ω (w, deg) |
82.246067 |
| M (ma, deg) |
0.000117 |
Magnitude
Scatter + Global Linear
$$
M_a = (7.781 + 5.487\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
7.781 |
| n |
5.487 |
| gf |
1.000 |
| gb |
-0.906 |
| 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
Residuals (Piecewise)
$$\epsilon = a \log_{10} r_{\mathrm{au}} + b$$
| Start (UTC) |
End (UTC) |
a |
b |
| 2021-05-24 |
2024-04-12 |
+10.1462 |
-9.061 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-05-12 00:00 |
12:58:35.20 |
+03:43:12.5 |
HIP 63487 |
29.53 |
| 2026-05-12 12:00 |
12:58:28.37 |
+03:43:01.8 |
HIP 63487 |
31.15 |
| 2026-05-13 00:00 |
12:58:21.59 |
+03:42:50.7 |
HIP 63487 |
32.76 |
| 2026-05-13 12:00 |
12:58:14.87 |
+03:42:39.2 |
HIP 63209 |
33.90 |
| 2026-05-14 00:00 |
12:58:08.20 |
+03:42:27.2 |
HIP 63209 |
33.23 |
| 2026-05-14 12:00 |
12:58:01.58 |
+03:42:14.8 |
HIP 63209 |
32.64 |
| 2026-05-15 00:00 |
12:57:55.01 |
+03:42:01.9 |
HIP 63209 |
32.13 |
| 2026-05-15 12:00 |
12:57:48.50 |
+03:41:48.7 |
HIP 63209 |
31.72 |
| 2026-05-16 00:00 |
12:57:42.04 |
+03:41:35.0 |
HIP 63209 |
31.40 |
| 2026-05-16 12:00 |
12:57:35.64 |
+03:41:20.8 |
HIP 63209 |
31.17 |
| 2026-05-17 00:00 |
12:57:29.30 |
+03:41:06.3 |
HIP 63209 |
31.03 |
| 2026-05-17 12:00 |
12:57:23.01 |
+03:40:51.2 |
HIP 63209 |
30.98 |
| 2026-05-18 00:00 |
12:57:16.77 |
+03:40:35.8 |
HIP 63090 |
30.11 |
| 2026-05-18 12:00 |
12:57:10.60 |
+03:40:19.9 |
HIP 63090 |
28.69 |
| 2026-05-19 00:00 |
12:57:04.48 |
+03:40:03.6 |
HIP 63090 |
27.29 |
| 2026-05-19 12:00 |
12:56:58.42 |
+03:39:46.8 |
HIP 63090 |
25.91 |
| 2026-05-20 00:00 |
12:56:52.42 |
+03:39:29.6 |
HIP 63090 |
24.57 |
| 2026-05-20 12:00 |
12:56:46.47 |
+03:39:12.0 |
HIP 63090 |
23.25 |
| 2026-05-21 00:00 |
12:56:40.59 |
+03:38:53.9 |
HIP 63090 |
21.96 |
| 2026-05-21 12:00 |
12:56:34.76 |
+03:38:35.3 |
HIP 63090 |
20.70 |
| 2026-05-22 00:00 |
12:56:29.00 |
+03:38:16.4 |
HIP 63090 |
19.48 |
| 2026-05-22 12:00 |
12:56:23.29 |
+03:37:57.0 |
HIP 63090 |
18.30 |
| 2026-05-23 00:00 |
12:56:17.65 |
+03:37:37.1 |
HIP 63090 |
17.17 |
| 2026-05-23 12:00 |
12:56:12.07 |
+03:37:16.8 |
HIP 63090 |
16.10 |
| 2026-05-24 00:00 |
12:56:06.55 |
+03:36:56.1 |
HIP 63090 |
15.08 |
| 2026-05-24 12:00 |
12:56:01.09 |
+03:36:34.9 |
HIP 63090 |
14.13 |
| 2026-05-25 00:00 |
12:55:55.69 |
+03:36:13.3 |
HIP 63090 |
13.26 |
| 2026-05-25 12:00 |
12:55:50.35 |
+03:35:51.3 |
HIP 63090 |
12.49 |
| 2026-05-26 00:00 |
12:55:45.08 |
+03:35:28.8 |
HIP 63090 |
11.82 |
| 2026-05-26 12:00 |
12:55:39.87 |
+03:35:05.9 |
HIP 63090 |
11.27 |
| 2026-05-27 00:00 |
12:55:34.72 |
+03:34:42.6 |
HIP 63090 |
10.86 |
| 2026-05-27 12:00 |
12:55:29.63 |
+03:34:18.8 |
HIP 63090 |
10.60 |
| 2026-05-28 00:00 |
12:55:24.61 |
+03:33:54.6 |
HIP 63090 |
10.48 |
| 2026-05-28 12:00 |
12:55:19.65 |
+03:33:29.9 |
HIP 63090 |
10.52 |
| 2026-05-29 00:00 |
12:55:14.76 |
+03:33:04.8 |
HIP 63090 |
10.70 |
| 2026-05-29 12:00 |
12:55:09.93 |
+03:32:39.3 |
HIP 63090 |
11.01 |
| 2026-05-30 00:00 |
12:55:05.16 |
+03:32:13.3 |
HIP 63090 |
11.45 |
| 2026-05-30 12:00 |
12:55:00.46 |
+03:31:46.9 |
HIP 63090 |
11.98 |
| 2026-05-31 00:00 |
12:54:55.83 |
+03:31:20.1 |
HIP 63090 |
12.60 |
| 2026-05-31 12:00 |
12:54:51.26 |
+03:30:52.8 |
HIP 63090 |
13.29 |
| 2026-06-01 00:00 |
12:54:46.75 |
+03:30:25.1 |
HIP 63090 |
14.04 |
| 2026-06-01 12:00 |
12:54:42.31 |
+03:29:57.0 |
HIP 63090 |
14.83 |
| 2026-06-02 00:00 |
12:54:37.94 |
+03:29:28.5 |
HIP 63090 |
15.65 |