| Parameter |
Value |
| Designation |
C/2020 A3 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2019-06-28T20:34:35.627520Z |
| Orbit solution date (soln_date, UTC) |
2023-01-14T00:12:32Z |
| Obs used |
94 |
| NEO |
- |
| M1 |
6.800 |
| K1 |
11.250 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2020-01-07T14:18:44.640000Z |
| Discovery magnitude (MPC) |
18.92 o |
| Discovery observatory (MPC) |
T08 · ATLAS-MLO, Mauna Loa |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-10-25.0000000 |
| e |
0.99890265 |
| q (au) |
5.766807 |
| a (au) |
5255.225488 |
| i (deg) |
146.700275 |
| Ω (om, deg) |
120.792469 |
| ω (w, deg) |
268.410013 |
| M (ma, deg) |
0.000306 |
Magnitude
Scatter + Global Linear
$$
M_a = (2.943 + 6.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
2.943 |
| n |
6.000 |
| gf |
1.000 |
| gb |
-0.501 |
| k |
1.000 |
| 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) |
| 2026-09-20 00:00 |
07:29:44.87 |
+31:12:17.4 |
HIP 36383 |
5.95 |
| 2026-09-20 12:00 |
07:29:46.60 |
+31:12:40.4 |
HIP 36383 |
6.24 |
| 2026-09-21 00:00 |
07:29:48.28 |
+31:13:03.6 |
HIP 36383 |
6.54 |
| 2026-09-21 12:00 |
07:29:49.90 |
+31:13:26.9 |
HIP 36383 |
6.86 |
| 2026-09-22 00:00 |
07:29:51.46 |
+31:13:50.5 |
HIP 36383 |
7.19 |
| 2026-09-22 12:00 |
07:29:52.96 |
+31:14:14.3 |
HIP 36383 |
7.53 |
| 2026-09-23 00:00 |
07:29:54.40 |
+31:14:38.2 |
HIP 36383 |
7.87 |
| 2026-09-23 12:00 |
07:29:55.77 |
+31:15:02.3 |
HIP 36383 |
8.22 |
| 2026-09-24 00:00 |
07:29:57.09 |
+31:15:26.7 |
HIP 36383 |
8.57 |
| 2026-09-24 12:00 |
07:29:58.34 |
+31:15:51.2 |
HIP 36383 |
8.92 |
| 2026-09-25 00:00 |
07:29:59.53 |
+31:16:15.9 |
HIP 36383 |
9.27 |
| 2026-09-25 12:00 |
07:30:00.66 |
+31:16:40.7 |
HIP 36484 |
9.52 |
| 2026-09-26 00:00 |
07:30:01.73 |
+31:17:05.8 |
HIP 36484 |
9.76 |
| 2026-09-26 12:00 |
07:30:02.73 |
+31:17:31.0 |
HIP 36484 |
10.02 |
| 2026-09-27 00:00 |
07:30:03.67 |
+31:17:56.5 |
HIP 36484 |
10.30 |
| 2026-09-27 12:00 |
07:30:04.55 |
+31:18:22.1 |
HIP 36484 |
10.61 |
| 2026-09-28 00:00 |
07:30:05.36 |
+31:18:47.9 |
HIP 36484 |
10.93 |
| 2026-09-28 12:00 |
07:30:06.11 |
+31:19:13.9 |
HIP 36484 |
11.27 |
| 2026-09-29 00:00 |
07:30:06.80 |
+31:19:40.0 |
HIP 36484 |
11.63 |
| 2026-09-29 12:00 |
07:30:07.42 |
+31:20:06.4 |
HIP 36484 |
12.00 |
| 2026-09-30 00:00 |
07:30:07.97 |
+31:20:32.9 |
HIP 36484 |
12.39 |
| 2026-09-30 12:00 |
07:30:08.47 |
+31:20:59.6 |
HIP 36484 |
12.78 |
| 2026-10-01 00:00 |
07:30:08.89 |
+31:21:26.5 |
HIP 36484 |
13.19 |
| 2026-10-01 12:00 |
07:30:09.26 |
+31:21:53.6 |
HIP 36484 |
13.61 |
| 2026-10-02 00:00 |
07:30:09.55 |
+31:22:20.8 |
HIP 36383 |
14.02 |
| 2026-10-02 12:00 |
07:30:09.78 |
+31:22:48.2 |
HIP 36383 |
14.34 |
| 2026-10-03 00:00 |
07:30:09.95 |
+31:23:15.8 |
HIP 36383 |
14.66 |
| 2026-10-03 12:00 |
07:30:10.05 |
+31:23:43.6 |
HIP 36383 |
14.98 |
| 2026-10-04 00:00 |
07:30:10.08 |
+31:24:11.6 |
HIP 36383 |
15.30 |
| 2026-10-04 12:00 |
07:30:10.04 |
+31:24:39.7 |
HIP 36383 |
15.62 |
| 2026-10-05 00:00 |
07:30:09.94 |
+31:25:08.0 |
HIP 36383 |
15.94 |
| 2026-10-05 12:00 |
07:30:09.77 |
+31:25:36.5 |
HIP 36383 |
16.26 |
| 2026-10-06 00:00 |
07:30:09.53 |
+31:26:05.2 |
HIP 36383 |
16.58 |
| 2026-10-06 12:00 |
07:30:09.23 |
+31:26:34.0 |
HIP 36383 |
16.90 |
| 2026-10-07 00:00 |
07:30:08.85 |
+31:27:03.1 |
HIP 36383 |
17.22 |
| 2026-10-07 12:00 |
07:30:08.41 |
+31:27:32.2 |
HIP 36383 |
17.54 |
| 2026-10-08 00:00 |
07:30:07.90 |
+31:28:01.6 |
HIP 36383 |
17.86 |
| 2026-10-08 12:00 |
07:30:07.32 |
+31:28:31.1 |
HIP 36383 |
18.18 |
| 2026-10-09 00:00 |
07:30:06.67 |
+31:29:00.8 |
HIP 36383 |
18.51 |
| 2026-10-09 12:00 |
07:30:05.95 |
+31:29:30.7 |
HIP 36383 |
18.84 |
| 2026-10-10 00:00 |
07:30:05.17 |
+31:30:00.7 |
HIP 36383 |
19.17 |
| 2026-10-10 12:00 |
07:30:04.31 |
+31:30:31.0 |
HIP 36383 |
19.51 |
| 2026-10-11 00:00 |
07:30:03.38 |
+31:31:01.3 |
HIP 36383 |
19.85 |