| 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) |
| 2026-05-12 00:00 |
19:34:38.64 |
-28:14:40.8 |
HIP 96124 |
29.43 |
| 2026-05-12 12:00 |
19:34:32.81 |
-28:15:46.7 |
HIP 96124 |
28.83 |
| 2026-05-13 00:00 |
19:34:26.88 |
-28:16:52.8 |
HIP 96124 |
28.32 |
| 2026-05-13 12:00 |
19:34:20.86 |
-28:17:58.9 |
HIP 96124 |
27.88 |
| 2026-05-14 00:00 |
19:34:14.75 |
-28:19:05.3 |
HIP 96094 |
26.77 |
| 2026-05-14 12:00 |
19:34:08.54 |
-28:20:11.7 |
HIP 96094 |
25.29 |
| 2026-05-15 00:00 |
19:34:02.24 |
-28:21:18.3 |
HIP 96094 |
23.83 |
| 2026-05-15 12:00 |
19:33:55.84 |
-28:22:25.0 |
HIP 96094 |
22.39 |
| 2026-05-16 00:00 |
19:33:49.36 |
-28:23:31.9 |
HIP 96094 |
20.98 |
| 2026-05-16 12:00 |
19:33:42.78 |
-28:24:38.9 |
HIP 96094 |
19.62 |
| 2026-05-17 00:00 |
19:33:36.11 |
-28:25:46.0 |
HIP 96094 |
18.33 |
| 2026-05-17 12:00 |
19:33:29.34 |
-28:26:53.2 |
HIP 96094 |
17.12 |
| 2026-05-18 00:00 |
19:33:22.49 |
-28:28:00.5 |
HIP 96094 |
16.01 |
| 2026-05-18 12:00 |
19:33:15.55 |
-28:29:07.9 |
HIP 96094 |
15.05 |
| 2026-05-19 00:00 |
19:33:08.51 |
-28:30:15.5 |
HIP 96094 |
14.25 |
| 2026-05-19 12:00 |
19:33:01.39 |
-28:31:23.1 |
HIP 96094 |
13.67 |
| 2026-05-20 00:00 |
19:32:54.18 |
-28:32:30.8 |
HIP 96094 |
13.33 |
| 2026-05-20 12:00 |
19:32:46.88 |
-28:33:38.7 |
HIP 96094 |
13.26 |
| 2026-05-21 00:00 |
19:32:39.49 |
-28:34:46.6 |
HIP 96094 |
13.47 |
| 2026-05-21 12:00 |
19:32:32.01 |
-28:35:54.6 |
HIP 96094 |
13.96 |
| 2026-05-22 00:00 |
19:32:24.45 |
-28:37:02.6 |
HIP 96094 |
14.71 |
| 2026-05-22 12:00 |
19:32:16.81 |
-28:38:10.8 |
HIP 96094 |
15.68 |
| 2026-05-23 00:00 |
19:32:09.07 |
-28:39:19.0 |
HIP 96094 |
16.84 |
| 2026-05-23 12:00 |
19:32:01.26 |
-28:40:27.3 |
HIP 96094 |
18.16 |
| 2026-05-24 00:00 |
19:31:53.35 |
-28:41:35.7 |
HIP 96094 |
19.61 |
| 2026-05-24 12:00 |
19:31:45.37 |
-28:42:44.1 |
HIP 96094 |
21.18 |
| 2026-05-25 00:00 |
19:31:37.30 |
-28:43:52.6 |
HIP 96094 |
22.84 |
| 2026-05-25 12:00 |
19:31:29.15 |
-28:45:01.1 |
HIP 96094 |
24.57 |
| 2026-05-26 00:00 |
19:31:20.92 |
-28:46:09.7 |
HIP 96094 |
26.37 |
| 2026-05-26 12:00 |
19:31:12.61 |
-28:47:18.3 |
HIP 96094 |
28.22 |
| 2026-05-27 00:00 |
19:31:04.21 |
-28:48:27.0 |
HIP 96094 |
30.13 |
| 2026-05-27 12:00 |
19:30:55.74 |
-28:49:35.7 |
HIP 95782 |
28.02 |
| 2026-05-28 00:00 |
19:30:47.18 |
-28:50:44.4 |
HIP 95782 |
25.89 |
| 2026-05-28 12:00 |
19:30:38.55 |
-28:51:53.2 |
HIP 95782 |
23.76 |
| 2026-05-29 00:00 |
19:30:29.84 |
-28:53:01.9 |
HIP 95782 |
21.62 |
| 2026-05-29 12:00 |
19:30:21.06 |
-28:54:10.8 |
HIP 95782 |
19.49 |
| 2026-05-30 00:00 |
19:30:12.19 |
-28:55:19.6 |
HIP 95782 |
17.37 |
| 2026-05-30 12:00 |
19:30:03.25 |
-28:56:28.4 |
HIP 95782 |
15.27 |
| 2026-05-31 00:00 |
19:29:54.24 |
-28:57:37.2 |
HIP 95782 |
13.21 |
| 2026-05-31 12:00 |
19:29:45.15 |
-28:58:46.1 |
HIP 95782 |
11.22 |
| 2026-06-01 00:00 |
19:29:35.98 |
-28:59:54.9 |
HIP 95782 |
9.36 |
| 2026-06-01 12:00 |
19:29:26.74 |
-29:01:03.8 |
HIP 95782 |
7.73 |
| 2026-06-02 00:00 |
19:29:17.43 |
-29:02:12.6 |
HIP 95782 |
6.52 |