C/2019 U5 (PANSTARRS)
Metadata
| Parameter | Value |
|---|---|
| Designation | C/2019 U5 (PANSTARRS) |
| Type | C |
| Perihelion (tp_cal, UTC) | 2023-03-29T21:50:14.012160Z |
| Orbit solution date (soln_date, UTC) | 2026-01-13T08:12:19Z |
| Obs used | 5417 |
| NEO | - |
| M1 | 8.200 |
| K1 | 5.750 |
| PC | - |
| Discovery observation (MPC, UTC) | 2019-10-22T05:17:08.131200Z |
| Discovery magnitude (MPC) | 21.16 w |
| Discovery observatory (MPC) | F51 · Pan-STARRS 1, Haleakala |
Osculating Elements
| Parameter | Value |
|---|---|
| Epoch (epoch_cal, TDB) | 2022-09-26.0000000 |
| e | 1.00143088 |
| q (au) | 3.624066 |
| a (au) | -2532.751079 |
| i (deg) | 113.521208 |
| Ω (om, deg) | 2.637189 |
| ω (w, deg) | 181.509010 |
| M (ma, deg) | -0.001430 |
Magnitude
Scatter + Global Linear
$$ M_a = (7.215 + 2.197\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta $$ $$ \theta = 180^\circ - \alpha $$ $$ \Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b) $$ $$ \Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1 $$
Model Parameters
| Parameter | Value |
|---|---|
| H0 | 7.215 |
| n | 2.197 |
| gf | 1.000 |
| gb | -0.994 |
| k | 1.000 |
| δ90 | 9.996 |
| 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 |
|---|---|---|---|
| 2019-10-11 | 2022-03-07 | +5.0737 | -3.967 |
| 2022-03-07 | 2023-03-29 | +0.8289 | -0.711 |
| 2023-03-29 | 2024-06-07 | -3.5286 | +2.036 |
| 2024-06-07 | 2025-11-30 | +0.0779 | -0.350 |
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) |
|---|---|---|---|---|
| 2026-02-03 00:00 | 04:26:08.91 | -44:23:05.5 | HIP 20630 | 16.12 |
| 2026-02-03 12:00 | 04:25:56.67 | -44:20:02.5 | HIP 20630 | 12.37 |
| 2026-02-04 00:00 | 04:25:44.61 | -44:16:59.0 | HIP 20630 | 8.63 |
| 2026-02-04 12:00 | 04:25:32.75 | -44:13:54.9 | HIP 20630 | 4.90 |
| 2026-02-05 00:00 | 04:25:21.06 | -44:10:50.3 | HIP 20630 | 1.23 |
| 2026-02-05 12:00 | 04:25:09.56 | -44:07:45.2 | HIP 20630 | 2.56 |
| 2026-02-06 00:00 | 04:24:58.25 | -44:04:39.7 | HIP 20582 | 6.00 |
| 2026-02-06 12:00 | 04:24:47.12 | -44:01:33.7 | HIP 20582 | 2.95 |
| 2026-02-07 00:00 | 04:24:36.18 | -43:58:27.3 | HIP 20582 | 2.95 |
| 2026-02-07 12:00 | 04:24:25.42 | -43:55:20.4 | HIP 20582 | 5.98 |
| 2026-02-08 00:00 | 04:24:14.85 | -43:52:13.1 | HIP 20582 | 9.47 |
| 2026-02-08 12:00 | 04:24:04.46 | -43:49:05.4 | HIP 20582 | 13.04 |
| 2026-02-09 00:00 | 04:23:54.26 | -43:45:57.4 | HIP 20582 | 16.64 |
| 2026-02-09 12:00 | 04:23:44.23 | -43:42:49.0 | HIP 20514 | 15.43 |
| 2026-02-10 00:00 | 04:23:34.39 | -43:39:40.3 | HIP 20514 | 12.42 |
| 2026-02-10 12:00 | 04:23:24.74 | -43:36:31.2 | HIP 20514 | 9.82 |
| 2026-02-11 00:00 | 04:23:15.26 | -43:33:21.8 | HIP 20514 | 8.00 |
| 2026-02-11 12:00 | 04:23:05.97 | -43:30:12.1 | HIP 20514 | 7.55 |
| 2026-02-12 00:00 | 04:22:56.86 | -43:27:02.2 | HIP 20514 | 8.68 |
| 2026-02-12 12:00 | 04:22:47.93 | -43:23:52.0 | HIP 20514 | 10.88 |
| 2026-02-13 00:00 | 04:22:39.18 | -43:20:41.6 | HIP 20514 | 13.64 |
| 2026-02-13 12:00 | 04:22:30.61 | -43:17:30.9 | HIP 20514 | 16.69 |
| 2026-02-14 00:00 | 04:22:22.22 | -43:14:20.0 | HIP 20514 | 19.87 |
| 2026-02-14 12:00 | 04:22:14.00 | -43:11:08.9 | HIP 20514 | 23.14 |
| 2026-02-15 00:00 | 04:22:05.97 | -43:07:57.7 | HIP 20374 | 20.98 |
| 2026-02-15 12:00 | 04:21:58.12 | -43:04:46.3 | HIP 20374 | 17.61 |
| 2026-02-16 00:00 | 04:21:50.44 | -43:01:34.7 | HIP 20374 | 14.31 |
| 2026-02-16 12:00 | 04:21:42.94 | -42:58:23.0 | HIP 20374 | 11.12 |
| 2026-02-17 00:00 | 04:21:35.61 | -42:55:11.3 | HIP 20374 | 8.16 |
| 2026-02-17 12:00 | 04:21:28.46 | -42:51:59.4 | HIP 20374 | 5.77 |
| 2026-02-18 00:00 | 04:21:21.49 | -42:48:47.4 | HIP 20374 | 4.86 |
| 2026-02-18 12:00 | 04:21:14.69 | -42:45:35.4 | HIP 20374 | 6.11 |
| 2026-02-19 00:00 | 04:21:08.07 | -42:42:23.3 | HIP 20374 | 8.61 |
| 2026-02-19 12:00 | 04:21:01.61 | -42:39:11.2 | HIP 20365 | 8.05 |
| 2026-02-20 00:00 | 04:20:55.33 | -42:35:59.1 | HIP 20365 | 8.51 |
| 2026-02-20 12:00 | 04:20:49.22 | -42:32:47.0 | HIP 20365 | 10.13 |
| 2026-02-21 00:00 | 04:20:43.28 | -42:29:34.9 | HIP 20365 | 12.45 |
| 2026-02-21 12:00 | 04:20:37.51 | -42:26:22.8 | HIP 20365 | 15.16 |
| 2026-02-22 00:00 | 04:20:31.91 | -42:23:10.8 | HIP 20365 | 18.07 |
| 2026-02-22 12:00 | 04:20:26.48 | -42:19:58.9 | HIP 20365 | 21.10 |
| 2026-02-23 00:00 | 04:20:21.22 | -42:16:47.0 | HIP 20199 | 20.29 |
| 2026-02-23 12:00 | 04:20:16.12 | -42:13:35.3 | HIP 20199 | 16.96 |
| 2026-02-24 00:00 | 04:20:11.19 | -42:10:23.6 | HIP 20199 | 13.65 |