| 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 |
0.996 |
| gb |
-0.500 |
| k |
0.974 |
| δ90 |
9.985 |
| 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 |
21:59:35.51 |
+54:25:46.2 |
HIP 108476 |
10.12 |
| 2026-07-29 12:00 |
21:59:25.44 |
+54:25:58.6 |
HIP 108476 |
8.67 |
| 2026-07-30 00:00 |
21:59:15.33 |
+54:26:10.1 |
HIP 108476 |
7.24 |
| 2026-07-30 12:00 |
21:59:05.19 |
+54:26:20.7 |
HIP 108476 |
5.84 |
| 2026-07-31 00:00 |
21:58:55.00 |
+54:26:30.4 |
HIP 108476 |
4.49 |
| 2026-07-31 12:00 |
21:58:44.78 |
+54:26:39.2 |
HIP 108476 |
3.27 |
| 2026-08-01 00:00 |
21:58:34.52 |
+54:26:47.0 |
HIP 108476 |
2.41 |
| 2026-08-01 12:00 |
21:58:24.23 |
+54:26:54.0 |
HIP 108476 |
2.34 |
| 2026-08-02 00:00 |
21:58:13.90 |
+54:27:00.0 |
HIP 108476 |
3.11 |
| 2026-08-02 12:00 |
21:58:03.53 |
+54:27:05.1 |
HIP 108476 |
4.31 |
| 2026-08-03 00:00 |
21:57:53.14 |
+54:27:09.3 |
HIP 108476 |
5.66 |
| 2026-08-03 12:00 |
21:57:42.71 |
+54:27:12.5 |
HIP 108476 |
7.09 |
| 2026-08-04 00:00 |
21:57:32.25 |
+54:27:14.8 |
HIP 108476 |
8.56 |
| 2026-08-04 12:00 |
21:57:21.76 |
+54:27:16.2 |
HIP 108476 |
10.05 |
| 2026-08-05 00:00 |
21:57:11.25 |
+54:27:16.7 |
HIP 108476 |
11.55 |
| 2026-08-05 12:00 |
21:57:00.70 |
+54:27:16.2 |
HIP 108476 |
13.07 |
| 2026-08-06 00:00 |
21:56:50.13 |
+54:27:14.7 |
HIP 108476 |
14.59 |
| 2026-08-06 12:00 |
21:56:39.53 |
+54:27:12.4 |
HIP 108183 |
13.82 |
| 2026-08-07 00:00 |
21:56:28.91 |
+54:27:09.1 |
HIP 108183 |
12.30 |
| 2026-08-07 12:00 |
21:56:18.27 |
+54:27:04.8 |
HIP 108183 |
10.79 |
| 2026-08-08 00:00 |
21:56:07.60 |
+54:26:59.6 |
HIP 108183 |
9.29 |
| 2026-08-08 12:00 |
21:55:56.91 |
+54:26:53.5 |
HIP 108183 |
7.81 |
| 2026-08-09 00:00 |
21:55:46.20 |
+54:26:46.4 |
HIP 108183 |
6.36 |
| 2026-08-09 12:00 |
21:55:35.47 |
+54:26:38.3 |
HIP 108183 |
5.00 |
| 2026-08-10 00:00 |
21:55:24.72 |
+54:26:29.3 |
HIP 108183 |
3.80 |
| 2026-08-10 12:00 |
21:55:13.96 |
+54:26:19.4 |
HIP 108183 |
2.99 |
| 2026-08-11 00:00 |
21:55:03.18 |
+54:26:08.5 |
HIP 108183 |
2.90 |
| 2026-08-11 12:00 |
21:54:52.39 |
+54:25:56.6 |
HIP 108183 |
3.60 |
| 2026-08-12 00:00 |
21:54:41.58 |
+54:25:43.8 |
HIP 108183 |
4.76 |
| 2026-08-12 12:00 |
21:54:30.76 |
+54:25:30.0 |
HIP 108183 |
6.13 |
| 2026-08-13 00:00 |
21:54:19.93 |
+54:25:15.3 |
HIP 108183 |
7.59 |
| 2026-08-13 12:00 |
21:54:09.09 |
+54:24:59.6 |
HIP 108183 |
9.10 |
| 2026-08-14 00:00 |
21:53:58.24 |
+54:24:42.9 |
HIP 108183 |
10.65 |
| 2026-08-14 12:00 |
21:53:47.39 |
+54:24:25.3 |
HIP 108183 |
12.22 |
| 2026-08-15 00:00 |
21:53:36.53 |
+54:24:06.8 |
HIP 108183 |
13.80 |
| 2026-08-15 12:00 |
21:53:25.66 |
+54:23:47.3 |
HIP 108183 |
15.40 |
| 2026-08-16 00:00 |
21:53:14.79 |
+54:23:26.8 |
HIP 108183 |
17.00 |
| 2026-08-16 12:00 |
21:53:03.92 |
+54:23:05.4 |
HIP 107874 |
15.61 |
| 2026-08-17 00:00 |
21:52:53.04 |
+54:22:43.0 |
HIP 107874 |
14.00 |
| 2026-08-17 12:00 |
21:52:42.17 |
+54:22:19.7 |
HIP 107874 |
12.39 |
| 2026-08-18 00:00 |
21:52:31.30 |
+54:21:55.4 |
HIP 107874 |
10.77 |
| 2026-08-18 12:00 |
21:52:20.43 |
+54:21:30.2 |
HIP 107874 |
9.16 |
| 2026-08-19 00:00 |
21:52:09.56 |
+54:21:04.0 |
HIP 107874 |
7.54 |