| Parameter |
Value |
| Designation |
C/2020 U5 (PANSTARRS) |
| Type |
C |
| Perihelion (tp_cal, UTC) |
2022-04-27T21:04:17.325120Z |
| Orbit solution date (soln_date, UTC) |
2024-04-13T16:42:29Z |
| Obs used |
509 |
| NEO |
- |
| M1 |
12.200 |
| K1 |
4.750 |
| 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) |
2022-01-04.0000000 |
| e |
0.99935367 |
| q (au) |
3.755932 |
| a (au) |
5811.146481 |
| i (deg) |
97.271094 |
| Ω (om, deg) |
107.337920 |
| ω (w, deg) |
75.415390 |
| M (ma, deg) |
359.999747 |
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 |
1.000 |
| 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)
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-03-26 00:00 |
19:36:28.91 |
-26:47:51.6 |
HIP 96273 |
33.69 |
| 2026-03-26 12:00 |
19:36:32.21 |
-26:48:34.8 |
HIP 96273 |
33.80 |
| 2026-03-27 00:00 |
19:36:35.41 |
-26:49:18.3 |
HIP 96273 |
33.93 |
| 2026-03-27 12:00 |
19:36:38.52 |
-26:50:02.1 |
HIP 96273 |
34.06 |
| 2026-03-28 00:00 |
19:36:41.55 |
-26:50:46.2 |
HIP 96273 |
34.20 |
| 2026-03-28 12:00 |
19:36:44.48 |
-26:51:30.5 |
HIP 96273 |
34.35 |
| 2026-03-29 00:00 |
19:36:47.32 |
-26:52:15.1 |
HIP 96273 |
34.51 |
| 2026-03-29 12:00 |
19:36:50.07 |
-26:53:00.0 |
HIP 96273 |
34.68 |
| 2026-03-30 00:00 |
19:36:52.73 |
-26:53:45.2 |
HIP 96273 |
34.85 |
| 2026-03-30 12:00 |
19:36:55.30 |
-26:54:30.6 |
HIP 96273 |
35.02 |
| 2026-03-31 00:00 |
19:36:57.78 |
-26:55:16.3 |
HIP 96273 |
35.20 |
| 2026-03-31 12:00 |
19:37:00.16 |
-26:56:02.3 |
HIP 96273 |
35.39 |
| 2026-04-01 00:00 |
19:37:02.46 |
-26:56:48.6 |
HIP 96273 |
35.57 |
| 2026-04-01 12:00 |
19:37:04.66 |
-26:57:35.1 |
HIP 96645 |
35.05 |
| 2026-04-02 00:00 |
19:37:06.76 |
-26:58:21.9 |
HIP 96645 |
34.17 |
| 2026-04-02 12:00 |
19:37:08.78 |
-26:59:09.0 |
HIP 96645 |
33.30 |
| 2026-04-03 00:00 |
19:37:10.70 |
-26:59:56.4 |
HIP 96645 |
32.44 |
| 2026-04-03 12:00 |
19:37:12.53 |
-27:00:44.0 |
HIP 96645 |
31.60 |
| 2026-04-04 00:00 |
19:37:14.26 |
-27:01:31.9 |
HIP 96645 |
30.78 |
| 2026-04-04 12:00 |
19:37:15.90 |
-27:02:20.1 |
HIP 96645 |
29.97 |
| 2026-04-05 00:00 |
19:37:17.44 |
-27:03:08.6 |
HIP 96645 |
29.17 |
| 2026-04-05 12:00 |
19:37:18.89 |
-27:03:57.3 |
HIP 96645 |
28.40 |
| 2026-04-06 00:00 |
19:37:20.25 |
-27:04:46.4 |
HIP 96645 |
27.64 |
| 2026-04-06 12:00 |
19:37:21.51 |
-27:05:35.7 |
HIP 96645 |
26.91 |
| 2026-04-07 00:00 |
19:37:22.67 |
-27:06:25.2 |
HIP 96645 |
26.20 |
| 2026-04-07 12:00 |
19:37:23.74 |
-27:07:15.1 |
HIP 96645 |
25.51 |
| 2026-04-08 00:00 |
19:37:24.71 |
-27:08:05.2 |
HIP 96645 |
24.85 |
| 2026-04-08 12:00 |
19:37:25.59 |
-27:08:55.6 |
HIP 96645 |
24.21 |
| 2026-04-09 00:00 |
19:37:26.37 |
-27:09:46.3 |
HIP 96645 |
23.61 |
| 2026-04-09 12:00 |
19:37:27.05 |
-27:10:37.2 |
HIP 96645 |
23.04 |
| 2026-04-10 00:00 |
19:37:27.63 |
-27:11:28.5 |
HIP 96645 |
22.50 |
| 2026-04-10 12:00 |
19:37:28.12 |
-27:12:20.0 |
HIP 96645 |
22.01 |
| 2026-04-11 00:00 |
19:37:28.51 |
-27:13:11.7 |
HIP 96645 |
21.55 |
| 2026-04-11 12:00 |
19:37:28.80 |
-27:14:03.8 |
HIP 96645 |
21.14 |
| 2026-04-12 00:00 |
19:37:29.00 |
-27:14:56.1 |
HIP 96645 |
20.77 |
| 2026-04-12 12:00 |
19:37:29.09 |
-27:15:48.7 |
HIP 96645 |
20.46 |
| 2026-04-13 00:00 |
19:37:29.09 |
-27:16:41.5 |
HIP 96645 |
20.19 |
| 2026-04-13 12:00 |
19:37:28.99 |
-27:17:34.6 |
HIP 96645 |
19.99 |
| 2026-04-14 00:00 |
19:37:28.79 |
-27:18:28.0 |
HIP 96645 |
19.84 |
| 2026-04-14 12:00 |
19:37:28.49 |
-27:19:21.7 |
HIP 96645 |
19.75 |
| 2026-04-15 00:00 |
19:37:28.09 |
-27:20:15.6 |
HIP 96645 |
19.73 |
| 2026-04-15 12:00 |
19:37:27.59 |
-27:21:09.8 |
HIP 96645 |
19.76 |
| 2026-04-16 00:00 |
19:37:27.00 |
-27:22:04.3 |
HIP 96645 |
19.86 |