C/2020 U5 (PANSTARRS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2020 U5 (PANSTARRS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2022-04-27T21:03:44.562240Z |
| Orbit solution date (soln_date, UTC) | 2026-06-09T11:12:25Z |
| Obs used | 513 |
| NEO | - |
| M1 | 12.300 |
| K1 | 4.500 |
| PC | - |
| Discovery observation (MPC, UTC) | 2020-10-22T13:23:23.510400Z |
| Discovery magnitude (MPC) | 20.43 w |
| Discovery observatory (MPC) | F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2022-01-02.0000000 |
| e | 0.99935524 |
| q (au) | 3.755932 |
| a (au) | 5825.303368 |
| i (deg) | 97.271131 |
| Ω (om, deg) | 107.337973 |
| ω (w, deg) | 75.415330 |
| M (ma, deg) | 359.999743 |
Magnitude
Scatter + Global Linear
$$ M_a = (12.222 + 3.489\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 12.222 |
| n | 3.489 |
| gf | 0.997 |
| gb | -0.746 |
| 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 |
|---|---|---|---|
| 2020-09-25 | 2021-02-22 | -0.3995 | +0.308 |
| 2021-02-22 | 2022-04-21 | +0.9626 | -0.954 |
| 2022-04-28 | 2022-12-15 | +3.8477 | -1.840 |
| 2022-12-15 | 2024-04-09 | +7.4296 | -4.434 |
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) |
|---|---|---|---|---|
| 2026-09-20 00:00 | 18:54:18.94 | -31:43:57.3 | HIP 92723 | 17.53 |
| 2026-09-20 12:00 | 18:54:16.26 | -31:44:10.6 | HIP 92723 | 17.07 |
| 2026-09-21 00:00 | 18:54:13.67 | -31:44:23.8 | HIP 92723 | 16.64 |
| 2026-09-21 12:00 | 18:54:11.18 | -31:44:36.8 | HIP 92723 | 16.23 |
| 2026-09-22 00:00 | 18:54:08.78 | -31:44:49.7 | HIP 92723 | 15.83 |
| 2026-09-22 12:00 | 18:54:06.49 | -31:45:02.3 | HIP 92723 | 15.46 |
| 2026-09-23 00:00 | 18:54:04.29 | -31:45:14.8 | HIP 92723 | 15.11 |
| 2026-09-23 12:00 | 18:54:02.20 | -31:45:27.1 | HIP 92723 | 14.77 |
| 2026-09-24 00:00 | 18:54:00.20 | -31:45:39.2 | HIP 92723 | 14.45 |
| 2026-09-24 12:00 | 18:53:58.30 | -31:45:51.1 | HIP 92723 | 14.15 |
| 2026-09-25 00:00 | 18:53:56.49 | -31:46:02.9 | HIP 92723 | 13.87 |
| 2026-09-25 12:00 | 18:53:54.79 | -31:46:14.5 | HIP 92723 | 13.60 |
| 2026-09-26 00:00 | 18:53:53.18 | -31:46:25.9 | HIP 92723 | 13.34 |
| 2026-09-26 12:00 | 18:53:51.67 | -31:46:37.2 | HIP 92723 | 13.10 |
| 2026-09-27 00:00 | 18:53:50.26 | -31:46:48.3 | HIP 92723 | 12.87 |
| 2026-09-27 12:00 | 18:53:48.94 | -31:46:59.2 | HIP 92723 | 12.65 |
| 2026-09-28 00:00 | 18:53:47.72 | -31:47:10.0 | HIP 92723 | 12.43 |
| 2026-09-28 12:00 | 18:53:46.60 | -31:47:20.6 | HIP 92723 | 12.23 |
| 2026-09-29 00:00 | 18:53:45.58 | -31:47:31.1 | HIP 92723 | 12.04 |
| 2026-09-29 12:00 | 18:53:44.65 | -31:47:41.4 | HIP 92723 | 11.85 |
| 2026-09-30 00:00 | 18:53:43.82 | -31:47:51.5 | HIP 92723 | 11.67 |
| 2026-09-30 12:00 | 18:53:43.09 | -31:48:01.5 | HIP 92723 | 11.50 |
| 2026-10-01 00:00 | 18:53:42.45 | -31:48:11.4 | HIP 92723 | 11.33 |
| 2026-10-01 12:00 | 18:53:41.91 | -31:48:21.1 | HIP 92723 | 11.17 |
| 2026-10-02 00:00 | 18:53:41.46 | -31:48:30.7 | HIP 92723 | 11.01 |
| 2026-10-02 12:00 | 18:53:41.11 | -31:48:40.1 | HIP 92723 | 10.85 |
| 2026-10-03 00:00 | 18:53:40.86 | -31:48:49.4 | HIP 92723 | 10.69 |
| 2026-10-03 12:00 | 18:53:40.71 | -31:48:58.5 | HIP 92723 | 10.54 |
| 2026-10-04 00:00 | 18:53:40.65 | -31:49:07.6 | HIP 92723 | 10.39 |
| 2026-10-04 12:00 | 18:53:40.68 | -31:49:16.4 | HIP 92723 | 10.24 |
| 2026-10-05 00:00 | 18:53:40.81 | -31:49:25.2 | HIP 92723 | 10.10 |
| 2026-10-05 12:00 | 18:53:41.04 | -31:49:33.8 | HIP 92723 | 9.95 |
| 2026-10-06 00:00 | 18:53:41.36 | -31:49:42.3 | HIP 92723 | 9.81 |
| 2026-10-06 12:00 | 18:53:41.78 | -31:49:50.6 | HIP 92723 | 9.68 |
| 2026-10-07 00:00 | 18:53:42.29 | -31:49:58.9 | HIP 92723 | 9.54 |
| 2026-10-07 12:00 | 18:53:42.90 | -31:50:07.0 | HIP 92723 | 9.41 |
| 2026-10-08 00:00 | 18:53:43.60 | -31:50:14.9 | HIP 92723 | 9.29 |
| 2026-10-08 12:00 | 18:53:44.40 | -31:50:22.8 | HIP 92723 | 9.17 |
| 2026-10-09 00:00 | 18:53:45.29 | -31:50:30.5 | HIP 92723 | 9.06 |
| 2026-10-09 12:00 | 18:53:46.27 | -31:50:38.2 | HIP 92723 | 8.95 |
| 2026-10-10 00:00 | 18:53:47.35 | -31:50:45.7 | HIP 92723 | 8.86 |
| 2026-10-10 12:00 | 18:53:48.52 | -31:50:53.1 | HIP 92723 | 8.78 |
| 2026-10-11 00:00 | 18:53:49.79 | -31:51:00.4 | HIP 92723 | 8.72 |