C/2020 Y2 (ATLAS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2020 Y2 (ATLAS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2022-06-17T16:46:06.738240Z |
| Orbit solution date (soln_date, UTC) | 2024-12-26T20:12:24Z |
| Obs used | 1775 |
| NEO | - |
| M1 | 10.500 |
| K1 | 4.500 |
| PC | - |
| Discovery observation (MPC, UTC) | 2020-12-28T15:18:23.155200Z |
| Discovery magnitude (MPC) | 18.30 o |
| Discovery observatory (MPC) | T08 · ATLAS-MLO, Mauna Loa |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2022-09-03.0000000 |
| e | 0.99700512 |
| q (au) | 3.132490 |
| a (au) | 1045.948256 |
| i (deg) | 101.297766 |
| Ω (om, deg) | 26.515016 |
| ω (w, deg) | 266.105810 |
| M (ma, deg) | 0.002252 |
Magnitude
Scatter + Global Linear
$$ M_a = (11.072 + 2.941\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 11.072 |
| n | 2.941 |
| gf | 1.000 |
| gb | -0.718 |
| 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 |
|---|---|---|---|
| 2020-03-25 | 2021-01-29 | +12.9145 | -9.677 |
| 2021-01-29 | 2021-05-17 | -5.4955 | +4.015 |
| 2021-05-17 | 2022-06-01 | -2.1125 | +1.423 |
| 2022-06-19 | 2023-12-12 | -1.0342 | +0.680 |
| 2023-12-12 | 2024-10-29 | +16.6054 | -12.913 |
log10 r = log10(heliocentric distance / AU), Δ = geocentric distance (AU)
Finding Chart
Ephemeris
| Date/Time (UTC) | RA (J2000) | Dec (J2000) | Nearest HIP | Dist from HIP (arcmin) |
|---|---|---|---|---|
| 2026-03-26 00:00 | 00:41:11.49 | +26:55:52.7 | HIP 3275 | 17.01 |
| 2026-03-26 12:00 | 00:41:20.03 | +26:57:06.0 | HIP 3275 | 15.12 |
| 2026-03-27 00:00 | 00:41:28.57 | +26:58:19.6 | HIP 3275 | 13.35 |
| 2026-03-27 12:00 | 00:41:37.11 | +26:59:33.8 | HIP 3275 | 11.73 |
| 2026-03-28 00:00 | 00:41:45.66 | +27:00:48.3 | HIP 3275 | 10.36 |
| 2026-03-28 12:00 | 00:41:54.21 | +27:02:03.2 | HIP 3275 | 9.34 |
| 2026-03-29 00:00 | 00:42:02.77 | +27:03:18.6 | HIP 3275 | 8.80 |
| 2026-03-29 12:00 | 00:42:11.32 | +27:04:34.4 | HIP 3275 | 8.82 |
| 2026-03-30 00:00 | 00:42:19.87 | +27:05:50.6 | HIP 3275 | 9.41 |
| 2026-03-30 12:00 | 00:42:28.43 | +27:07:07.1 | HIP 3275 | 10.48 |
| 2026-03-31 00:00 | 00:42:36.98 | +27:08:24.1 | HIP 3275 | 11.89 |
| 2026-03-31 12:00 | 00:42:45.53 | +27:09:41.5 | HIP 3275 | 13.55 |
| 2026-04-01 00:00 | 00:42:54.09 | +27:10:59.3 | HIP 3275 | 15.37 |
| 2026-04-01 12:00 | 00:43:02.64 | +27:12:17.5 | HIP 3275 | 17.31 |
| 2026-04-02 00:00 | 00:43:11.18 | +27:13:36.0 | HIP 3275 | 19.32 |
| 2026-04-02 12:00 | 00:43:19.73 | +27:14:55.0 | HIP 3275 | 21.40 |
| 2026-04-03 00:00 | 00:43:28.27 | +27:16:14.3 | HIP 3275 | 23.51 |
| 2026-04-03 12:00 | 00:43:36.80 | +27:17:34.0 | HIP 3275 | 25.67 |
| 2026-04-04 00:00 | 00:43:45.33 | +27:18:54.1 | HIP 3331 | 25.96 |
| 2026-04-04 12:00 | 00:43:53.86 | +27:20:14.5 | HIP 3331 | 26.28 |
| 2026-04-05 00:00 | 00:44:02.38 | +27:21:35.4 | HIP 3331 | 26.79 |
| 2026-04-05 12:00 | 00:44:10.90 | +27:22:56.6 | HIP 3331 | 27.48 |
| 2026-04-06 00:00 | 00:44:19.40 | +27:24:18.1 | HIP 3331 | 28.34 |
| 2026-04-06 12:00 | 00:44:27.90 | +27:25:40.1 | HIP 3331 | 29.36 |
| 2026-04-07 00:00 | 00:44:36.40 | +27:27:02.4 | HIP 3331 | 30.51 |
| 2026-04-07 12:00 | 00:44:44.88 | +27:28:25.0 | HIP 3546 | 30.33 |
| 2026-04-08 00:00 | 00:44:53.36 | +27:29:48.0 | HIP 3546 | 28.56 |
| 2026-04-08 12:00 | 00:45:01.82 | +27:31:11.4 | HIP 3546 | 26.88 |
| 2026-04-09 00:00 | 00:45:10.28 | +27:32:35.1 | HIP 3546 | 25.30 |
| 2026-04-09 12:00 | 00:45:18.72 | +27:33:59.1 | HIP 3546 | 23.83 |
| 2026-04-10 00:00 | 00:45:27.16 | +27:35:23.5 | HIP 3546 | 22.50 |
| 2026-04-10 12:00 | 00:45:35.58 | +27:36:48.3 | HIP 3546 | 21.34 |
| 2026-04-11 00:00 | 00:45:43.99 | +27:38:13.3 | HIP 3546 | 20.38 |
| 2026-04-11 12:00 | 00:45:52.39 | +27:39:38.7 | HIP 3546 | 19.65 |
| 2026-04-12 00:00 | 00:46:00.77 | +27:41:04.5 | HIP 3546 | 19.16 |
| 2026-04-12 12:00 | 00:46:09.14 | +27:42:30.5 | HIP 3546 | 18.95 |
| 2026-04-13 00:00 | 00:46:17.50 | +27:43:56.9 | HIP 3546 | 19.02 |
| 2026-04-13 12:00 | 00:46:25.84 | +27:45:23.6 | HIP 3546 | 19.37 |
| 2026-04-14 00:00 | 00:46:34.16 | +27:46:50.6 | HIP 3546 | 19.99 |
| 2026-04-14 12:00 | 00:46:42.47 | +27:48:18.0 | HIP 3546 | 20.84 |
| 2026-04-15 00:00 | 00:46:50.77 | +27:49:45.6 | HIP 3546 | 21.90 |
| 2026-04-15 12:00 | 00:46:59.04 | +27:51:13.6 | HIP 3546 | 23.15 |
| 2026-04-16 00:00 | 00:47:07.30 | +27:52:41.8 | HIP 3546 | 24.56 |