| Parameter |
Value |
| Designation |
C/2020 Y3 (ATLAS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2020-12-03T11:39:47.134080Z |
| Orbit solution date (soln_date, UTC) |
2021-09-04T23:43:08Z |
| Obs used |
380 |
| NEO |
- |
| M1 |
13.900 |
| K1 |
8.750 |
| PC |
- |
| Discovery observation (MPC, UTC) |
2020-12-28T15:19:02.899200Z |
| Discovery magnitude (MPC) |
18.49 o |
| Discovery observatory (MPC) |
T08 · ATLAS-MLO, Mauna Loa |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2021-02-25.0000000 |
| e |
0.98676697 |
| q (au) |
1.999243 |
| a (au) |
151.079720 |
| i (deg) |
83.097062 |
| Ω (om, deg) |
191.426774 |
| ω (w, deg) |
342.043610 |
| M (ma, deg) |
0.044326 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.627 + 3.107\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.627 |
| n |
3.107 |
| gf |
0.999 |
| gb |
-0.500 |
| k |
0.974 |
| δ90 |
9.994 |
| 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 |
22:10:25.12 |
+51:38:46.6 |
HIP 109217 |
27.32 |
| 2026-05-12 12:00 |
22:10:28.02 |
+51:40:17.7 |
HIP 109217 |
27.56 |
| 2026-05-13 00:00 |
22:10:30.83 |
+51:41:48.9 |
HIP 109217 |
27.87 |
| 2026-05-13 12:00 |
22:10:33.55 |
+51:43:20.0 |
HIP 109217 |
28.26 |
| 2026-05-14 00:00 |
22:10:36.17 |
+51:44:51.1 |
HIP 109217 |
28.71 |
| 2026-05-14 12:00 |
22:10:38.71 |
+51:46:22.2 |
HIP 109217 |
29.22 |
| 2026-05-15 00:00 |
22:10:41.15 |
+51:47:53.2 |
HIP 109217 |
29.79 |
| 2026-05-15 12:00 |
22:10:43.50 |
+51:49:24.2 |
HIP 109533 |
29.73 |
| 2026-05-16 00:00 |
22:10:45.76 |
+51:50:55.2 |
HIP 109533 |
28.18 |
| 2026-05-16 12:00 |
22:10:47.93 |
+51:52:26.0 |
HIP 109533 |
26.63 |
| 2026-05-17 00:00 |
22:10:50.00 |
+51:53:56.9 |
HIP 109533 |
25.09 |
| 2026-05-17 12:00 |
22:10:51.98 |
+51:55:27.6 |
HIP 109533 |
23.55 |
| 2026-05-18 00:00 |
22:10:53.86 |
+51:56:58.3 |
HIP 109533 |
22.01 |
| 2026-05-18 12:00 |
22:10:55.66 |
+51:58:28.8 |
HIP 109533 |
20.48 |
| 2026-05-19 00:00 |
22:10:57.35 |
+51:59:59.3 |
HIP 109533 |
18.95 |
| 2026-05-19 12:00 |
22:10:58.96 |
+52:01:29.7 |
HIP 109533 |
17.42 |
| 2026-05-20 00:00 |
22:11:00.46 |
+52:03:00.0 |
HIP 109533 |
15.90 |
| 2026-05-20 12:00 |
22:11:01.88 |
+52:04:30.1 |
HIP 109533 |
14.38 |
| 2026-05-21 00:00 |
22:11:03.20 |
+52:06:00.2 |
HIP 109533 |
12.87 |
| 2026-05-21 12:00 |
22:11:04.42 |
+52:07:30.1 |
HIP 109533 |
11.36 |
| 2026-05-22 00:00 |
22:11:05.55 |
+52:08:59.8 |
HIP 109533 |
9.85 |
| 2026-05-22 12:00 |
22:11:06.59 |
+52:10:29.5 |
HIP 109533 |
8.35 |
| 2026-05-23 00:00 |
22:11:07.53 |
+52:11:58.9 |
HIP 109533 |
6.85 |
| 2026-05-23 12:00 |
22:11:08.37 |
+52:13:28.2 |
HIP 109533 |
5.37 |
| 2026-05-24 00:00 |
22:11:09.12 |
+52:14:57.4 |
HIP 109533 |
3.89 |
| 2026-05-24 12:00 |
22:11:09.78 |
+52:16:26.4 |
HIP 109533 |
2.44 |
| 2026-05-25 00:00 |
22:11:10.34 |
+52:17:55.2 |
HIP 109533 |
1.09 |
| 2026-05-25 12:00 |
22:11:10.80 |
+52:19:23.8 |
HIP 109533 |
0.92 |
| 2026-05-26 00:00 |
22:11:11.17 |
+52:20:52.3 |
HIP 109533 |
2.21 |
| 2026-05-26 12:00 |
22:11:11.44 |
+52:22:20.5 |
HIP 109506 |
2.80 |
| 2026-05-27 00:00 |
22:11:11.62 |
+52:23:48.6 |
HIP 109506 |
1.85 |
| 2026-05-27 12:00 |
22:11:11.70 |
+52:25:16.4 |
HIP 109506 |
1.81 |
| 2026-05-28 00:00 |
22:11:11.69 |
+52:26:44.0 |
HIP 109506 |
2.71 |
| 2026-05-28 12:00 |
22:11:11.58 |
+52:28:11.5 |
HIP 109506 |
3.95 |
| 2026-05-29 00:00 |
22:11:11.37 |
+52:29:38.6 |
HIP 109506 |
5.30 |
| 2026-05-29 12:00 |
22:11:11.07 |
+52:31:05.6 |
HIP 109506 |
6.68 |
| 2026-05-30 00:00 |
22:11:10.67 |
+52:32:32.3 |
HIP 109562 |
7.97 |
| 2026-05-30 12:00 |
22:11:10.18 |
+52:33:58.8 |
HIP 109562 |
9.25 |
| 2026-05-31 00:00 |
22:11:09.59 |
+52:35:25.0 |
HIP 109562 |
10.58 |
| 2026-05-31 12:00 |
22:11:08.90 |
+52:36:51.0 |
HIP 109403 |
11.70 |
| 2026-06-01 00:00 |
22:11:08.12 |
+52:38:16.7 |
HIP 109403 |
11.85 |
| 2026-06-01 12:00 |
22:11:07.24 |
+52:39:42.1 |
HIP 109403 |
12.15 |
| 2026-06-02 00:00 |
22:11:06.27 |
+52:41:07.3 |
HIP 109403 |
12.60 |